Reference Manual HP 5890 Series II and HP 5890 Series II Plus
DHewlett-Packard Company 1989, 1990, 1991, 1993, 1994 All Rights Reserved. Reproduction, adaptation, or translation without permission is prohibited, except as allowed under the copyright laws. HP part number 05890-90271 First edition—Jun 1989 Printed In U.S.A. Second edition—Oct 1989 Printed In U.S.A. Third edition—Jan 1990 Printed In U.S.A. Fourth edition—Oct 1990 Printed In U.S.A. Fifth edition—Oct 1991 Printed In U.S.A. Fifth edition—Mar 1993 Printed In U.S.A. Sixth edition—Jul 1994 Printed In U.S.A.
Contents Chapter 1 — Columns and Fittings . . . . . . . . . . . . . . . . . 9 Column oven . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Column placement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Packed column . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hewlett•Packardcapillary columns . . . . . . . . . . . . . . . . . . .
Contents Chapter 4 — Electronic Flow Sensing . . . . . . . . . . . . . . . 57 Displaying gas flow rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Designating gas type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electronic flow sensor (EFS) calibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Preparation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Chapter 6 — Inlet Systems . . . . . . . . . . . . . . . . . . . . . . . . . 99 Packed column inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Electronic flow sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Septum•purgedpacked column inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Problems at high inlet temperatures . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Chapter 8 — Preventive Maintenance . . . . . . . . . . . . . . Conditioning columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . (Re)Packing columns . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Packed column inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Changing septa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Contents Chapter 9 — Chromatographic Troubleshooting . . . . . . Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Baseline symptoms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Position . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Wander and drift . . . . . . . . . . . . . . . . . . . . . . . . . .
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1 Columns and Fittings
Columns and Fittings The HP 5890 SERIES II (hereafter referred to as HP 5890) provides flexibility in choices among inlets, columns, and detectors through use of liners and adapters, allowing any standard column to be used without sacrificing performance. Additional flexibility is gained through positions of inlets and detectors relative to each other and through the large internal volume of the oven. This section provides information for the following: C The column oven. C Fittings.
Columns and Fittings Column oven Column oven Figure 1-1 Inlet Ftg Det Ftg Nut Plate The Column Oven The oven door latch, located beneath the lower right corner of the door, is pressed upward to open the door. Motor•drivenflaps at the rear of the oven admit room air for cool down or near•ambientoperation, so the door is kept closed except for access to columns (the oven cools most efficiently with its door closed).
Columns and Fittings Column oven Column placement Generally, a column may be installed between any inlet and detector. A rigid 1/4•inchpacked glass column, however, if installed in the B (rear•most)inlet, can only be installed in the B (rear•most)detector. Distance relationships among inlets and detectors are shown in Figure 1•2.
Columns and Fittings Column oven Hewlett-Packard capillary columns Hewlett•Packardcapillary columns are wound on wire frames which mount on a pair of brackets which slip into slots at the top of the oven interior.
Columns and Fittings Fittings Figure 1-4. Column Hanger Part No. 1460-1914 Column Installed Installed Bracket for Hewlett-Packard Capillary Columns The bracket has two positions from which to hang the column wire frame. Depending upon frame diameter, use the position which best centers the column in the oven. Column ends should come off the bottom of the frame, making smooth curves to inlet and detector fittings.
Columns and Fittings Fittings C Graphite O•ringsor ferrules have excellent sealing quality and long service life, can be used continuously to 400^C, and are generally recommended for most applications, particularly capillary and glass columns. They are also recommended for inlet and detector liners, and for split/splitless capillary inlet inserts. Since they do not adhere permanently to glass or metal, they can be removed easily without damage to the column, tubing, liner, or insert.
Columns and Fittings Fittings Table 1-1. Typical Fittings for Columns and Inlet/Detector Liners, Adapters, and Inserts Type Description Typical Use Part No.
Columns and Fittings Liners/adapters and inserts, general Liners/adapters and inserts, general A liner/adapter is installed from below, inside the oven; it serves both as an adapter to mate the particular column to the inlet or detector and to provide correct internal volume for proper operation. Inserts are used with inlets only, and, when required, are installed from above, at the top of the inlet; these are discussed specifically later in this section (see Inlet inserts).
Columns and Fittings Liners/adapters and inserts, general Table 1-2.
Columns and Fittings Liners/adapters and inserts, general Table 1-3. Hardware and Recommended Fittings for Capillary Column Installation Capillary Columns HP Series 530 ¿ 320 ¿m ID 200 ¿m ID Metal/ Glass Recommended Column Fittings Capillary column nut and 1.0-mm graphite ferrule, or silicone O-ring(s) Capillary column nut and 0.
Columns and Fittings Inlet/detector liners/adapters Inlet/detector liners/adapters Interchangeable stainless steel liners/adapters, installed from inside the oven, are used with the packed column inlet, and with all detectors, depending upon the column to be installed.
Columns and Fittings Inlet/detector liners/adapters In addition, liners for the packed column inlet are available to accept glass inserts (discussed later) for reduced reactivity, to trap nonvolatile residues, or for use with an HP Series 530 ¿ capillary column. C No liner is used with 1/4•inchpacked glass columns. The long leg of the column fits into the inlet body, replacing the liner. Packing and glass wool plug must be below the tip of the needle for best results.
Columns and Fittings Inlet/detector liners/adapters Detector liners/adapters Figure 1-6 Liner/Adapter Typical Installed Detector Liner/Adapter Detectors require a liner/adapter to be installed when used with packed metal columns (either 1/8•or 1/4•inch),and with any type of capillary column. Normally, no liner is required with 1/4•inchpacked glass columns, since the leg of the column itself serves as the liner.
Columns and Fittings Inlet/detector liners/adapters ECD and TCD adapters A makeup gas adapter must be installed in the ECD or TCD base to install a capillary column, and to augment carrier flow through the column with additional gas flow needed for optimal detector operation. The adapter must be removed for packed column applications. In addition, to install an HP Series 530¿ capillary column in an ECD or TCD having no capillary makeup gas adapter, the following adapters are used: Part No.
Columns and Fittings Inlet/detector liners/adapters Liner/adapter installation Figure 1-7 Liner 1/4-inch Ferrule Liner Retainer Nut Capillary Column Nut Packed Column Inlet Liner for HP Series 530 ¿ Capillary Column Use 1-mm Graphite Ferrule Nut and Ferrule Installed on a Liner/Adapter With one exception, liners/adapters are installed in the same manner; if the liner/adapter has not been used before, a new ferrule must be installed.
Columns and Fittings Inlet inserts 1. Assemble a brass nut and graphite ferrule onto the liner/adapter. 2. Insert the liner/adapter straight into the detector base as far as possible. 3. Holding the liner/adapter in this position, tighten the nut finger•tight. 4. Use a wrench to tighten the nut an additional 1/4 turn. 5. Install the column; then heat the oven, inlet, and detector to desired operating temperatures and, only if necessary to stop leaks, tighten fittings further.
Columns and Fittings Inlet inserts WARNING Exercise care! the oven, and/or inlet, or detector fittings may be hot enough to cause burns. Figure 1-9 Flared End Insert Installing a Glass Insert in a Packed Column Inlet 1. In handling the insert, avoid contaminating its surface (particularly its interior). 2. Remove the septum retainer nut and septum. 3. Carefully remove the old insert (if present) by withdrawing it straight up.
Columns and Fittings Inlet inserts Note: For the liner and insert for an HP Series 530 ¿ capillary column, if the column is already installed, a new insert may not seat properly in the liner; the column may prevent it from dropping completely into the liner. If the insert does not drop completely into the liner, do not force it (either the liner or the column may shatter); instead, remove the column, seat the insert, and then replace the column. 5. Replace the septum and septum retainer nut.
Columns and Fittings Inlet inserts The split insert contains packing material (10% OV•1on 80/100 High Performance Chromosorb•W),held in place by silanized glass wool plugs, located immediately above a mixing chamber. This ensures proper volatilization and homogeneous mixing of the sample prior to its entry into the column. WARNING Exercise care! The oven, and/or inlet, or detector fittings may be hot enough to cause burns.
Columns and Fittings Inlet inserts Figure 1-11 Installation, Split/Splitless Capillary Inlet Insert 3. Using tweezers, forceps, or similar tool, remove any insert already in place. 4. Inspect the new insert to be installed: For a split mode insert, the end with the mixing chamber and packing is inserted first into the inlet. 5. Place a graphite or silicone O•ringon the insert, about 2 to 3 mm from its top end. 6. Install the insert, pressing it straight down, as far as possible, into the inlet.
Columns and Fittings Jet replacement, FIDs or NPDs Jet replacement, FIDs or NPDs Depending upon the column type (packed versus capillary) to be used, and/or analyses to be performed, exchanging the jet in an FID or NPD may be necessary. This must be done prior to column installation, and is particularly important in optimizing FID performance. Exchanging the jet in either an FID or an NPD is described in Chapter 8, Preventive Maintenance. Metal capillary columns Most metal capillary columns (0.6 to 1.
2 Keyboard and Displays
Keyboard and Displays Figure 2-1 ACTUAL HP 5890 SYSTEM SETPOINT READY OVEN FINAL TIME RATE RUN NOT READY INITIAL TIME Oven Status Alphanumeric Display STATUS STOP Instrument Status START Run Control TABLE Programmable Cool on Column Control Setpoint Storage Control ADD TIME DELETE OVEN TEMP INIT VALUE IINIT TIME RATE INJ A PRES INJ B PRES OVEN TRACK AUX TEMP INJ A TEMP INJ B TEMP DET A TEMP PREVIOUS NEXT FINAL VALUE FINAL TIME OVEN MAX DET B TEMP EQUIB TIME FLOW PARAM
Keyboard and Displays Displaying setpoints HP 5890 SERIES II (hereafter referred to as HP 5890) operation is monitored and controlled through its front panel keyboard, and alphanumeric and LED displays. Some instrument functions are monitored continuously: signal levels, temperatures, carrier gas flow rates (if electronic flow sensing is installed), and inlet purge valve status (if a split/splitless capillary inlet is installed). There are two general display areas: C Alphanumeric Display.
Keyboard and Displays Entering setpoints Examples of possible displays are provided where appropriate throughout the manual. If a particular function is not installed in your instrument, an appropriate message is displayed when the key corresponding to the function is pressed.
Keyboard and Displays Entering setpoints To display the function and its setpoint: Figure 2-4 (Instrument Function Key) ( A or B ) necessary for a few instrument functions then, EITHER ( through 0 .
Keyboard and Displays Entering setpoints can be used anytime during an entry, prior to pressing ENTER , to erase the entry in progress. The * disappears, and the original setpoint display is restored. CLEAR Rules regarding keyboard usage are summarized below: C An instrument function key, when pressed, is shown in the display along with its current setpoint value, and actual value for continuously monitored functions: signal levels, temperatures, flow rates.
Keyboard and Displays Keyboard operation, INET control C is used anytime during setpoint entry, prior to pressing to erase the entry in progress. C , if pressed when no setpoint entry is in progress, displays HP 5890 readiness . C Run Control Key START , if pressed while a setpoint entry is in progress, causes the entry to be aborted. C If a particular key is not valid, it is simply ignored if pressed during setpoint entry.
Keyboard and Displays Protecting setpoints Additional information regarding INET control is available in Chapter 5, Signal Output. Servicing may be required for one or more devices on the INET loop if communication cannot be established. Protecting setpoints The HP 5890 provides a keyboard lock feature to minimize possibility of stored setpoints being altered unintentionally.
Keyboard and Displays Loading default setpoints With the keyboard locked, Figure 2•6shows the display occurring if a setpoint entry is attempted: Figure 2-6 ACTUAL KEYBOARD SETPOINT LOCKED KEYBOARD LOCKED Message Display If the HP 5890 keyboard is locked while the instrument is under INET control, a setpoint file may be loaded into HP 5890 memory from the controller, but the loaded setpoints cannot then be edited at the HP 5890 keyboard until it is unlocked.
Keyboard and Displays Loading default setpoints Upon pressing ENTER , default setpoints are loaded into memory, erasing setpoints already present. Table 2•1lists resulting HP 5890 default setpoints. Table 2-1.
Keyboard and Displays Loading default setpoints Note that if the battery protecting memory should fail when main power is turned off, the default setpoints are loaded into memory when the battery is replaced. In addition, calibration constants for oven temperature control and gas flow rate monitoring are also reset to default values.
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3 Temperature Control
Temperature Control Oven temperature, and temperatures of up to five separate heated zones (detectors, inlets, and/or heated valves), are controlled through keys shown in Figure 3•1.
Temperature Control Note that the ACTUAL value is a measured quantity, while the SETPOINT value is user•defined:in this example, the setpoint value for oven temperature might recently have been changed from 250 to 350^C, and the oven is now heating to the new setpoint. Given sufficient time for equilibration, ACTUAL and SETPOINT values become equal. .
Temperature Control Valid setpoint ranges Valid setpoint ranges Table 3•1lists valid setpoint ranges for the 13 keys controlling oven and heated zone temperatures. Table 3-1. Valid Setpoint Ranges For Temperature Control Keys Valid Setpoint Range Key In Increments Of Function OVEN TEMP -80 to 450 INIT TEMP -80 to 450 ^ 1^C INIT TIME 0 to 650.00 0.01 minute Oven Control RATE 0 to 70 0.1 /minute Oven Control FINAL TEMP -80 to 450 1 C Oven Control FINAL TIME 0 to 650.00 0.
Temperature Control Cryogenic (sub-ambient) oven control Cryogenic (sub-ambient) oven control Liquid N1 or liquid CO1 cryogenic options are for operation at temperatures less than about 7^C above ambient. This is done through operation of a valve which opens when coolant is demanded and closes when the setpoint temperature is reached. CRYO PARAM CRYO PARAM CRYO PARAM When you press gold you scroll through a series of displays for choosing cryogenic options.
Temperature Control Cryogenic (sub-ambient) oven control Figure 3-4 75 50 9 ^9 CRYO OFF at ambient +15 25 ^ CRYO ON at ambient + 25 (CRYO ON) Oven profile using CRYO, for operation during runs at subambient temperatures Figure 3- 5. 120 80 40 9 ^ CRYO BLAST ON ambient + 50 BLAST OFF 9 CRYO (30 sec.
Temperature Control Programming oven temperature Programming oven temperature HP 5890 oven temperature programming allows up to three ramps, in any combination of heating or cooling. Keys defining an oven temperature program include: INIT TEMP A setpoint temperature value at which the oven is maintained at the beginning of a temperature•programmed run. This is also the temperature to which the oven returns at termination of the temperature•programmedrun.
Temperature Control Oven status INIT TIME In isothermal operation ( RATE = 0 ), if is set equal to 0 (zero), the HP 5890 internally sets run time to the maximum, 650 minutes. A B is included in key sequences defining parameters for a second ramp; is included in key sequences defining parameters for a third ramp. In isothermal operation, and in one•or two•ramptemperature programs, rate for the next ramp must be set to 0 (zero) to prevent further programming.
Temperature Control Oven safety In complex two•or three•rampoven temperature programs, information as to the part of the program in progress is monitored by pressing OVEN TEMP . Note that, during a ramp, the SETPOINT value displayed is that calculated to be the correct temperature, based upon specified heating/cooling rate, and initial and final oven temperatures.
Temperature Control Fault: messages The message displayed when this occurs is shown in Figure 3•6. Figure 3-6 ACTUAL WARN: OVEN SHUT SETPOINT OFF Message, Oven SHUT DOWN The oven remains off until switched on again via the keyboard ON ( OVEN TEMP ), unless a FAULT: message is displayed (see below, Fault: messages). Power to the instrument must be switched off, and then on again to restore operation (setpoints are maintained).
Temperature Control After a power failure . . . Figure 3-7 ACTUAL FAULT: ADC OFFSET FAULT: LINE SENSE FAULT: INJA TEMP ACTUAL ACTUAL DETA TEMP OVEN FAULT: OVEN TEMP SETPOINT SETPOINT RDG ACTUAL > SETPOINT RDG ACTUAL FAULT: SETPOINT RDG ACTUAL FAULT: SETPOINT SETPOINT MAX+20 Thermal Control FAULT: Messages In addition to the message, the red NOT READY LED blinks.
Temperature Control Oven temperature calibration Figure 3-8 ACTUAL PASSED SELF TEST OVEN RATE SETPOINT STATUS FINAL TIME INITIAL TIME RUN NOT READY Message Display, Power Failure and Recovery Heated zones return to their respective setpoint values, after which the oven returns to its setpoint value.
Temperature Control Oven temperature calibration The HP 5890 provides the means to (if necessary) reset oven temperature monitoring so the displayed ACTUAL value accurately represents the correct temperature.
Temperature Control Oven temperature calibration 3. CALIB DELTA is displayed until ENTER is pressed; then oven temperature recalibration occurs. Note that, after calibration, the displayed oven temperature value should match closely the measured value. Any delta value within the range -10.00 through +10.00 ^C may be entered. If a value outside this range is entered, the message CORRECTION TOO HIGH is displayed.
4 Electronic Flow Sensing
Electronic Flow Sensing Two channels of electronic flow rate sensing continuously monitor gas flow rates (usually carrier) in the HP 5890 SERIES II. Proper scaling of displayed values for different commonly used gases is defined through keyboard entries. The two flow channels are distinguished through A and B . If carrier gas flows are monitored, A implies flow through column A (nearest the instrument front); B implies flow through column B (nearest the instrument rear).
Electronic Flow Sensing Designating gas type Designating gas type To scale the displayed flow rate value properly, one of four commonly used gases must be designated. The appropriate gas type is selected according to Table 4•1: Table 4-1.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration Electronic flow sensor (EFS) calibration Electronic flow sensor (EFS) calibration may be performed any time to ensure displayed flow rate accurately represents real gas flow rate through the sensor. The EFS is factory•calibratedfor four standard gases, H1, He, N1, and Ar/CH3, within the flow rate range of 0 to 100 ml/min. This covers the majority of chromatographic applications.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration Preparation 1. Access the EFS by removing the left side panel; remove two screws along its lower edge, slide the panel toward the rear of the instrument, and then lift. 2. Through the keyboard, select CALIB AND TEST mode, function 2: CLEAR . 2 ENTER GAIN A is displayed, followed by two values: the observed flow rate through Channel A, and the current gain calibration value for Channel A.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration 3. Locate the EFS module and note its labelling: CHANNEL A/ CHANNEL B, IN/OUT. For the channel being calibrated, locate and disconnect its OUT fitting; use two wrenches in opposition to prevent twisting the tubes. Figure 4-2 Outlet Line, Channel B Outlet Line, Channel A EFS Module Detail, Electronic Flow Sensor (EFS) Module 4. Install the EFS flow•measuringadapter (Part No. 05890•80620)into the female OUT fitting to the EFS module.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration Figure 4-3 EFS Flow-Measuring Adapter (Part No. 05890-80620) 5. Assuming there is no gas flow through the channel being calibrated, press ENTER at the keyboard. This updates the zero calibration value. Setting the GAIN calibration value After the zero calibration value is set at zero flow rate through the given channel, the gain calibration value must be set, based upon a measured flow rate. 1.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration Note: The HP 5890 has a timer function that may be used as an aid in measuring flow rate (see the Operating Manual, Chapter 4). C Press C After obtaining the desired flow rate, press: CLEAR C to access the timer function. TIME . ENTER 2 to return to setting the gain value. EFS channel A is assumed. Press calibrated. B if Channel B is being 4. Allow ample time for flow rate to equilibrate (no drift should be observed). 5.
Electronic Flow Sensing Electronic flow sensor (EFS) calibration Entering specific ZERO and GAIN values Calibration values for zero and gain should be recorded when a particular channel is calibrated. They can then be reentered through the keyboard if necessary, without repeating the entire calibration procedure. To enter specific zero and gain calibration values: 1. Select CALIB AND TEST mode, function 2: CLEAR .
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5 Signal Output
Signal Output A standard signal channel, controlled via SIG 1 , always is provided. A second signal channel, controlled via SIG 2 , is provided if Option 550/ Accessory 19242A (Communications Interface Board ), or Option 560/ Accessory 19254A (RS•232), is installed. Output sources include detector signal(s), heated zone or oven temperatures, carrier gas flow rates, column compensation run data, or test chromatographic data.
Signal Output Zeroing signal output The function of ZERO is to subtract a constant background signal from the detector signal. Background signal sources include the detector itself (background level depending upon detector type), column bleed, or contaminants in supply gas(es).
Signal Output Zeroing signal output Self- ZERO setpoint Referencing Figure 5•2for the +1 V output, note that using ZERO can increase dynamic range available for signal output by shifting an existing constant offset signal to a lower level (usually electrical zero). There are limits to this, however, so it is good practice to have background reduced as much as possible by minimizing column bleed, using clean supply gases, and by performing proper detector maintenance.
Signal Output Zeroing signal output Figure 5-3 1 mV Output: Canceling Baseline Offset (the self- ZERO function) 1.0 mV maximum output level O + 1.000 mV U T P U T 0.9 mV usable dynamic range V O L T A + 0.100 mV G E ZERO 1.0 mV usable dynamic range ENTER pressed Constant 0.1 mV detector background signal + 0.006 mV HP 5890 SERIES II electrical zero 0 mV Effect of ZERO on the +1 mV Analog Output The example in Figure 5•2is in terms of the +1 V analog output.
Signal Output Signal attenuation Note: If a self• ZERO determination is performed on an active signal exceeding the maximum permitted setpoint value for ZERO (see User•defined ZERO setpoint), the maximum setpoint value is assigned and the message SIG 1 (or 2) ZERO TOO HIGH is displayed. User-defined ZERO setpoint If the self• ZERO setpoint value determination is not appropriate for a particular application, any value from -830000.0 through 830000.0 may be entered at the keyboard.
Signal Output Signal attenuation Thus, signal output level at the +1 mV analog output may be set separately from that at the +1 V output. Table 5•2gives values permitted for either function, and the output affected. Table 5-2.
Signal Output Signal attenuation For analytical information from a detector, proper settings for RANGE 2!( ) and ATTN 2!( ) are determined such that peaks of interest are on scale at the integrator or chart recorder: peaks of interest must neither flat top by exceeding the allowed maximum output level, nor be too small to be measured. Table 5•3lists maximum detector output producing +1 volt at the +1V output for each RANGE 2!( ) setpoint value. Table 5-3.
Signal Output Signal attenuation From Table 5•3,note that for a TCD, RANGE 2!( ) = 0 is suitable for virtually all applications since the entire linear output range of the detector is included. Likewise, RANGE 2!( ) settings from 0 through 5 cover the entire useful output range for an ECD. Only an FID or NPD may require use of the higher RANGE 2!( ) settings.
Signal Output Signal attenuation Note that if RANGE 2!( ) or ATTN 2!( ) is pressed without first pressing SIG 1 SIG 2 or , SIGNAL 1 channel is assumed (and displayed). If desired, SIG 2 can then be pressed to display the same function for the SIGNAL 2 channel.
Signal Output Test signal output Test signal output A test chromatogram, consisting of three peaks, is permanently stored in the HP 5890. Each peak is approximately 1/10 the height of the previous peak, with the first (tallest) peak having a height value of about 125 mV at RANGE 2!( ) = 0 (+ 1 V analog output); half•heightwidth of this peak is about 0.13 minutes.
Signal Output Test signal output To access this function, the following key sequence is entered: SIG 1 (or SIG 2 ) 9 ENTER Test plot mode is confirmed by the display SIGNAL 1 (or 2) TEST PLOT. Pressing SIG 1 (or SIG 2 ) a second time displays the current signal level value (which is 0.0 initially). This permits monitoring the output signal. The chromatogram is initiated by pressing START . The chromatogram continues to cycle until STOP is pressed. Each cycle is about 1•1/2 minutes in length.
Signal Output Instrument network (INET) Instrument network (INET) The Instrument Network (INET) is a path for various devices to communicate with each other (data and/or commands). INET permits a group of devices (consisting of a controller, and some number of data Producers and data Consumers) to function as a single, unified system. INET permits: C Management of active workspace (described below) among instruments, a controller, and storage and print media.
Signal Output Instrument network (INET) Figure 5-6 Sampler IN OUT S/ECM OUT IN OUT IN 5890 HP 5890 SERIES II Gas Chromatograph Controller & Integrator Typical INET Loop Each INET must have one (and only one) device defined as the controller. The controller is responsible for network configuration when the network is first connected and powered on. The controller then retains this status for subsequent loop operations, maintaining its responsibility as network traffic manager.
Signal Output Instrument network (INET) configuration, consult appropriate manual(s) for the controller device (the HP 5890 is never a controller). An instrument Addresses An instrument is a device, housing together a collection of functions, and having a single model number. It has a single pair (IN and OUT) of INET cable connections. The INET controller assigns each instrument a unique address, in order, around the loop. Thus, addresses correspond to the physical order of connections around the loop.
Signal Output Instrument network (INET) Except for the controller, each instrument handles setpoints for instrument(s) other than itself only as blocks of data to be transmitted, but not altered. Active workspace Each device in an INET loop provides storage area for its own setpoints and parameters. These individual storage areas (each containing setpoints and parameters for the specific instrument) are also available to any other device in the loop.
Signal Output Instrument network (INET) INET operation In using the INET function, chromatographic parameters are entered normally through the HP 5890 keyboard. Integration parameters are entered at the controller. Parameters for other devices on the INET loop may be entered at the controller, or at their own keyboards. Collectively, the separate sets of parameters constitute a single set of parameters for an analysis. The intent here is to discuss INET operation only from the point of view of the HP 5890.
Signal Output Instrument network (INET) If a setpoint entry at the HP 5890 keyboard is in progress when a workfile or method is stored or listed at the controller, the entry is aborted. After the operation finishes, the HP 5890 returns to the same setpoint display. C When a stored workfile or method is recalled to active workspace at the controller, its setpoints are automatically downloaded into devices on the INET loop, including the HP 5890.
Signal Output INET configuration Automatic INET reconfiguration In the following circumstances, INET automatically reconfigures under direction of the controller: C Recovery from a power failure. C Recovery from any particular device on the loop being switched off, then on again. C Recovery from a disconnected (then reconnected) loop cable. Consult appropriate manuals for the controller in the event of problems arising from any of these circumstances.
Signal Output INET configuration Figure 5•8shows displays resulting from the key sequence: CLEAR . ENTER 3 Switching between Global and Local With regard to the INET function at the HP 5890, there are two operating modes: global or local. In global mode (default mode), HP 5890 START and STOP keys, when pressed, affect other devices on the INET loop. In local mode, however, pressing START or STOP at the HP 5890 affects only the HP 5890.
Signal Output INET configuration Note that global mode has two states: if GLOBAL flashes (default mode) when displayed, the HP 5890 is in global mode, but not configured into the INET system. When the HP 5890 is properly configured into the INET system, GLOBAL is displayed continuously. This feature provides a convenient diagnostic to determine if system configuration has occurred (at least as far as the HP 5890 is concerned).
Signal Output INET configuration The specific number shown depends upon how INET cables are connected among devices included in the loop. The value shown in the example (8) implies the HP 5890 is the first instrument on the loop, starting from the OUT receptacle on the controller device (the controller is always defined as 0). A 9 indicates the HP 5890 is the second device on the loop, etc, to a maximum value of 31.
Signal Output INET configuration Figure 5•11 shows resulting displays. Figure 5-11 INET-HP 5890 Signal Definition ACTUAL GLOBAL ADDR: ACTUAL SIG 1 ON RANGED SIG 1 ON FULL ACTUAL 2 SETPOINT SETPOINT RANGE ACTUAL SIG SETPOINT 8,31 SETPOINT OFF INET Signal Definition Displays From the displays, the following may be noted: C HP 5890 signal channels are designated SIG 1 or SIG 2.
Signal Output HP-IL loopback test C RANGED versus FULL RANGE indicates the dynamic range for the data to be transmitted to other devices on the loop; dynamic range for RANGED data is set at the HP 5890 according to the setpoint for RANGE 2!( ) . Dynamic range for FULL RANGE data is limited only by the detector itself. The choice of the type of data to be transmitted is set at the controller.
Signal Output HP-IL loopback test Figure 5-12 ACTUAL HPIL LOOPBACK ACTUAL PASSED SELF SELF SETPOINT TEST ACTUAL FAILED SETPOINT TEST SETPOINT TEST HPIL LOOPBACK TEST Displays The message PASSED SELF TEST indicates INET, at least with respect to the HP 5890, is performing satisfactorily. If FAILED SELF-TEST is displayed, a bad cable may be indicated; install a different INET cable and repeat the test.
Signal Output Warn: and fault: messages Warn: and fault: messages Figure 5-13 ACTUAL WARN: INET WARN: SIGNAL WARN: NO FAULT: INET SETPOINT TIMEOUT ACTUAL SETPOINT CHANGED ACTUAL ACTUAL INET CPU ACTUAL FAULT: INET RAM ACTUAL FAULT: INET ROM ACTUAL FAULT: ATTN1 DAO1 SETPOINT RAM SETPOINT TEST SETPOINT TEST SETPOINT TEST ACTUAL FAULT: SETPOINT CPU ACTUAL FAULT: SETPOINT DETECTORS SETPOINT TEST Signal Control WARN: and FAULT: Messages Figure 5•13shows possible WARN: and F
Signal Output Warn: and fault: messages C WARN: SIGNAL CHANGED and/or WARN: NO DETECTORS is displayed if a detector previously assigned to a particular signal channel is found to be absent; for example, if the signal board for a given detector should fail or be removed for service. C FAULT: INET CPU is displayed if the processor (and/or its associated circuitry) for HP 5890 INET operations should fail. HP 5890 diagnostics generating the above message displays are active at all times in normal operation.
Signal Output File compatibility with data handling devices File compatibility with data handling devices You must have the HP 5890 SERIES II in the proper mode for file compatibility with your data handling device. What are the modes? There are 2 file transfer modes: HP 5890A and HP 5890 SERIES II.
Signal Output File compatibility with data handling devices Figure 5-14 ACTUAL HP 5890A mode EMULATION MODE OK ACTUAL HP 5890 SERIES II mode SETPOINT SETPOINT PASSED SELF TEST GC Displays for File Transfer Modes How do I change modes? 1. Turn power off. 2. Remove the GC side panel, and locate the main PC board. Figure 5-15 Top Hinge for Grounding Main PC Board Finding the Main PC Board. 3. Find component P15 on the main PC board.
Signal Output File compatibility with data handling devices Figure 5-16 P6 P5 P15 P2 P3 P13 P12 Main PC Board Finding component P15 on the Main PC Board. 4. Set the jumper (Part No. 1258•0141)for the proper mode. To avoid electrostatic damage to the main board, ground yourself to the GC chassis with an ESD strap, or touch an unpainted area of the oven such as the door hinge. Figure 5-17 HP 5890A mode Setting the jumper.
Signal Output File compatibility with data handling devices How to convert HP 339X Integrator workfiles from 5890A to SERIES II mode: 1. Turn the GC off. 2. Follow the previous instructions to set the GC for 5890A mode (use proper grounding). 3. Download the workfile from the integrator. 4. Turn GC power off. 5. Remove the P15 jumper. (Now the GC is in SERIES II mode.) 6. Turn GC power on. 7. Add SERIES II setpoints (time table, etc). 8. Store the workfile at the integrator.
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6 Inlet Systems
Inlet Systems This chapter provides information for the following HP 5890 SERIES II (hereafter referred to as HP 5890) inlet systems: C Packed column inlet C Septum•purgedpacked column inlet C Split/splitless capillary inlet For cool on•columninformation, see the manual Programmable Cool On•ColumnInlet. Maintenance information is provided in Chapter 8, Preventive Maintenance.
Inlet Systems Packed column inlet Figure 6-1 Septum Retainer Nut Septum Liner Glass Insert Carrier Gas Graphite Ferrule Swage-type Nut and Ferrules Column Packed Column Inlet 101
Inlet Systems Packed column inlet Figure 6-2 Trap(s) External Internal Plumbing Plumbing Mass Flow Controller Carrier Gas Packed Column Inlet Pressure Gauge Electronic Flow Sensor (optional) To Detector Column Flow Diagram, Packed Column Inlet (with electronic flow sensor) Liquid sample is rapidly volatilized inside the inlet. To ensure complete volatilization, inlet temperature typically should be at least 20^C greater than the highest oven temperature to be used.
Inlet Systems Packed column inlet Assuming the system to be leak•free(and if total flow is < 200 ml/min), after setting the desired column flow rate, total flow through the system should be noted via the EFS. The original column flow rate is reestablished simply by adjusting the mass flow controller so the original total system flow rate value is displayed again.
Inlet Systems Packed column inlet Problems at high inlet temperatures A common problem with conventional packed column inlets operated at high temperatures is septum bleed and the associated ghost peaks. To minimize this effect, some inlet systems are designed with steep temperature gradients throughout the entire upper length of the inlet to provide a cool septum and minimal ghost peaks.
Inlet Systems Packed column inlet Figure 6-4 ^ Injection Port Setpoint Temperature 350 C Bottom of Septum 10 20 30 Syringe Tip 40 50 60 70 80 90 ^ Base of Injection Port 50 35 C Ove n100 ^ 150 C Oven ^ 300 C Oven 150 200 250 300 350 Temperature in Gas Stream — C ^ 400 Thermal Profiles This optimized thermal profile allows very reproducible results and virtually eliminates injection port discrimination against high boiling point components.
Inlet Systems Packed column inlet When operating the inlet with septum purge, low bleed septa are unnecessary and the selection of septa should be made primarily for good sealing and extended septa life reasons. On a periodic basis (every 1 to 2 months), the Teflon•coatedO•ring sealing the purge cavity should be replaced.
Inlet Systems Split/splitless capillary inlet Split/splitless capillary inlet Figure 6-5 A. CAPILLARY COLUMN Sealing O-Ring 1 Insert 1, 2, or 3 2 Split 3 Direct Injection Splitless B. PACKED COLUMN Item No. 1 1 2 3 4 5* Description Part Number Sealing O-Ring Split Insert (packed)18740-60840 Split Insert (unpacked)18740-80190 Direct Injection Insert18740-80200 Splitless Insert 18740-80220 Available 1/8-in. Column Insert18709-80030 for Purchase 1/4-in.
Inlet Systems Split/splitless capillary inlet The multiple•modesplit/splitless capillary inlet system may be used with any of the common types of capillary columns (fused silica, quartz, glass, metal). Specific sampling modes include: C Split, for major•componentanalyses. C Purged splitless, for trace•componentanalyses. Each mode requires installation of a specific inlet insert.
Inlet Systems Split/splitless capillary inlet In general, the carrier gas is chosen to maximize component resolution and detector performance while minimizing overall analysis time. Figure 6•7,a family of van Deemter curves for common carrier gases, illustrates the effect of gas choice and linear velocity (¿) on column efficiency (HETP, Height Equivalent to a Theoretical Plate) for a particular column and analysis. Figure 6-7 ^ C17 at 175 C k = 4.95 Glass W.C.O.T. OV-101 25 m x 0.25 mm 1.2 N2 1.0 H.E.T.
Inlet Systems Split/splitless capillary inlet Van Deemter curves demonstrate advantages of using either He or H1 as carrier gas. From the curves, several observations may be made: C Minima for He and H2 occur at much higher average linear velocities than N2. Thus, He, or even better, H2, can be used at far higher velocities than N2 with only small loss in efficiency. Use of H2 or He allows shorter overall analysis times.
Inlet Systems Split/splitless capillary inlet Table 6-1. Suggested Initial Column Pressures (kPa) for Various Capillary Column Bores and Lengths Nominal Length (m) Nominal ID (mm) 12 25 50 0.20 135 223 347 0.32 45 82 137 0.53 11 23 42 It must be emphasized that values in this table are recommended as starting points only! Values listed are independent of carrier gas used.
Inlet Systems Split/splitless capillary inlet Figure 6-8 External Internal Plumbing Plumbing Septum Purge Control Capillary Inlet (C) Trap(s) Mass Electronic Flow Flow Controller Sensor (optional) (P) IN N.C (S) COM N.
Inlet Systems Split/splitless capillary inlet The split ratio is an indicator of the fraction of total sample entering the column: the higher the value, the less sample enters the column. For setting flow for split sampling, see Chapter 4 of the HP 5890 Operating Manual. Verifying inlet purge status Verify that inlet purge flow is currently on, and will remain on throughout runs to be made in split sampling mode.
Inlet Systems Split/splitless capillary inlet Splitless sampling For splitless operation, the dilute sample is vaporized inside the inlet insert. Most of the sample is then swept onto the column. For full column efficiency, vaporized sample components must reconcentrate at the head of the column prior to separation; without reconcentration, peak widths of eluting components reflect inlet insert volume rather than column efficiency.
Inlet Systems Split/splitless capillary inlet Figure 6-9 Needle C Low Volatility Solute C High Volatility Solute (a) Carrier Gas Column (b) (c) (d) The Solvent Effect The solvent effect is described in great detail elsewhere: see Grob, K. and Grob, K., Jr., Journal of Chromatography, 94, page 53 (1974); Grob, K. and Grob, G., Chromatographia, 5, page 3 (1972).
Inlet Systems Split/splitless capillary inlet Table 6-2.
Inlet Systems Split/splitless capillary inlet A general guideline is that components boiling at least 150^C above the column temperature will be reconcentrated by cold trapping at the head of the column. Components with lower boiling points are reconcentrated via the solvent effect. Temperature programming Multiple•rampoven temperature programming is advantageous: the oven is held at an appropriately cool temperature at injection to create an environment for component reconcentration.
Inlet Systems Split/splitless capillary inlet A recommended procedure is to perform a series of analyses at increasingly higher inlet temperatures using components representative of those of interest, and analyzed using the conditions for later sample analyses. The optimum temperature is where maximum area counts are obtained, and there is no evidence of thermal degradation products.
Inlet Systems Split/splitless capillary inlet Figure 6-10 + 1.2% Deviation ~20 Area Counts ppm n-C14 (Cold Trapped) + 1.2% Deviation ~10 ppm n-C11 (Solvent Effect) Solvent: Isooctane Column: 16.5 m x 0.25 mm SE-54 80 C (0.5 min) 170^C @ 15^/min Sample Size: 1.
Inlet Systems Split/splitless capillary inlet Figure 6-11 External Internal Plumbing Plumbing Septum Purge Control Capillary Inlet (C) Trap(s) (P) IN Mass Electronic Flow Flow Sensor Controller (optional) N.C. COM (S) OUT GA IN N.O.
Inlet Systems Split/splitless capillary inlet Noting Figures 6•11 and 6•12,the splitless sampling process is as follows: C Before Injection: Carrier gas flow enters through the mass flow controller, into the top of the inlet. A small fraction is split off to purge the septum and insert seal, then flows on to the purge vent.
Inlet Systems Split/splitless capillary inlet 2. Wipe excess solvent from the syringe needle. 3. Without introducing air, draw in excess sample. 4. Position the syringe plunger for the required injection volume. Wipe excess sample from the needle. 5. Draw in air until the sample/solvent is entirely within the syringe barrel. The sample is ready for injection. This method results in the syringe filled as shown in Figure 6•13.
7 Detector Systems
Detector Systems This chapter provides information for the five HP 5890 SERIES II (hereafter referred to as HP 5890) detector systems: C Flame Ionization Detector (FID) C Nitrogen•PhosphorusDetector (NPD) C Electron Capture Detector (ECD) C Thermal Conductivity Detector (TCD) C Flame Photometric Detector (FPD) Capillary makeup gas flow rate Detectors are designed to operate best with a carrier flow rate of at least 20 ml/min, typical of packed column applications.
Detector Systems FID and NPD jets Supply pressure for capillary makeup gas should be set to about 276 kPa (40 psi). FID and NPD jets Depending upon the column type to be used, and/or analyses to be performed, exchanging the jet in an FID or NPD may be necessary. Table 7•1lists available jets. Note: If switching from packed column operation to capillary operation, the jet for capillary use must be installed prior to column installation. Table 7-1. Available FID / NPD Jets Part No.
Detector Systems Flame ionization detector (FID) Flame ionization detector (FID) Figure 7-1 FID Collector Assembly Inlet H2 Inlet Jet Flame Ionization Detector (FID) The flame ionization detector (FID) responds to compounds that produce ions when burned in a H1•airflame. These include all organic compounds, although a few (e.g., formic acid, acetaldehyde) exhibit poor sensitivity.
Detector Systems Flame ionization detector (FID) Compounds producing little or no response include: Rare gases Nitrogen Oxides Silicon Halides H1O NH2 N1 CO CO1 CS1 O1 N1 *CCl3 * Measured at the jet tip. This selectivity can be advantageous: for example, H1O or CS1, used as solvent, do not produce large solvent peaks. The system is linear for most organic compounds, from the minimum detectable limit through concentrations greater than 10% times the minimum detectable limit.
Detector Systems Flame ionization detector (FID) FID flameout problems When using pressure programming with large id columns (i.e. 530 ¿ columns) it is possible to blow the FID flame out if pressure (flow) becomes too high. If this occurs, either lower the pressure ramp or switch to a more restrictive column (longer and/or smaller id).
Detector Systems Nitrogen-phosphorus detector (NPD) Nitrogen-phosphorus detector (NPD) Figure 7-3 NPD Collector Assembly Air Inlet NPD Collector Active Element Jet H2 Inlet Nitrogen-Phosphorus Detector (NPD) The nitrogen•phosphorusdetector uses a jet and collector similar to the FID; however, the collector contains a small alumina cylinder coated with a rubidium salt (the active element) which is heated electrically.
Detector Systems Nitrogen-phosphorus detector (NPD) H1 and air are required, but at flows significantly less than those for an FID. Normal FID•typeionizations are therefore minimal, so response to compounds not containing nitrogen or phosphorus is reduced. Thus, the detector is both sensitive to and selective toward only compounds containing nitrogen and/or phosphorus. The electrical power for heating the active element is supplied through a toroidal transformer located inside the NPD detector cover.
Detector Systems Nitrogen-phosphorus detector (NPD) Other gas flow effects of too high flow rates of the hydrogen may allow a true flame to exist around the active element. This would overheat the active element severely and destroy the specific response. Too low flow rates of air tend to quench the background response of the active element, and this results in a re•equilibrationtime that is too long to establish proper background response (negative solvent peaks killing the active element).
Detector Systems Nitrogen-phosphorus detector (NPD) Performance considerations Contamination Very little contamination can create serious NPD problems. Common sources include: C Columns and/or glass wool treated with H2PO3 (phosphoric acid) C Phosphate•containingdetergents C Cyano•substitutedsilicone columns (XE•60,OV•225,etc.
Detector Systems Nitrogen-phosphorus detector (NPD) Residual silanizing reagents from derivatization, and/or bleed from silicone columns, may coat the active element with silicon dioxide. This decreases ionization efficiency, reducing sensitivity. If silanizing is necessary, remove excess reagent before injection. Silicone columns should be well conditioned and loaded less than 5%.
Detector Systems Nitrogen-phosphorus detector (NPD) Both detector baseline and sensitivity change with carrier flow rate due to change in temperature of the active element. This is the reason for the baseline drift in pressure•controlledinlet systems (capillary inlets) when temperature•programmingthe column. The amount of change in the detector response is proportional to the ratio of the total column flow change (temperature sensitive) to the makeup gas flow (not temperature sensitive), i.e.
Detector Systems Electron capture detector (ECD) Electron capture detector (ECD) WARNING The effluent gas stream from the detector must be vented to a fume hood to prevent possible contamination of the laboratory with radioactive material. Specific cleaning procedures are provided in Chapter 8, Preventive Maintenance. Requirements for USA owners WARNING Detector venting must be in conformance with the latest revision of Title 10, Code Of Federal Regulations, Part 20 (including Appendix B).
Detector Systems Electron capture detector (ECD) WARNING In the extremely unlikely event that both the oven and the ECD heated zone should go into thermal runaway (maximum, uncontrolled heating in excess of 400^C) at the same time, and that the ECD remains exposed to this condition for more than 12 hours, the following must be done: C After turning off main power and allowing the instrument to cool, cap ECD inlet and exhaust vent openings.
Detector Systems Electron capture detector (ECD) Figure 7-5 y Anode Anode Purge Vent Plated 63Ni Surface Nickel Plating Fused Silica Liner Makeup Gas Adapter Makeup Gas Column Electron Capture Detector (ECD) The electron capture detector (ECD) cell contains ]"Ni, a radioactive isotope emitting high•energyelectrons (µ•particles).These undergo repeated collisions with carrier gas molecules, producing about 100 secondary electrons for each initial µ•particle.
Detector Systems Electron capture detector (ECD) Uncaptured electrons are collected periodically by applying short•term voltage pulses to cell electrodes. This cell current is measured and compared to a reference current, and the pulse interval is then adjusted to maintain constant cell current. Therefore, pulse rate (frequency) rises when an electron•capturing compound is passing through the cell.
Detector Systems Electron capture detector (ECD) Table 7-2.
Detector Systems Electron capture detector (ECD) Considerations for packed column operation Either N1 or Ar containing 5 or 10% CH3, may be used as carrier gas. N1 yields somewhat higher sensitivity, but it is accompanied by higher noise; minimum detectable limit is about the same. N1 sometimes produces a negative solvent peak. Ar/CH3 gives greater dynamic range. The carrier gas must be dry and O1•free.Moisture and O1 traps are strongly recommended for highest sensitivity.
Detector Systems Electron capture detector (ECD) Background level If the ECD system becomes contaminated, whether from impurities in the carrier (or makeup) gas, or from column or septum bleed, a significant fraction of detector dynamic range may be lost. In addition, the output signal becomes noisy. To check background level, allow ample time for components from previous analyses to be flushed from the system, and then make a blank run (one with no sample injected).
Detector Systems Electron capture detector (ECD) A very clean system may produce a value below the low end of 10 (100 Hz). To correct this condition, an adjustment is made to the present potentiometer located on the ECD electronics board. ECD Potentiometer Switch Up: Adj Down: Fixed ECD Potentiometer Adjustment ECD Potentiometer Switch and Adjustment 1. Remove the right side of the panel. 2. Flip the switch up to the Adj. position. 3.
Detector Systems Thermal conductivity detector (TCD) Thermal conductivity detector (TCD) Figure 7-7 HP 5890 SERIES II TCD Cell VENT (60 ml/ min) VENT (60 ml/ min) 24 36 24 0 ml/min Switching Flow 1 (off) Filament Channel Filament Channel 24 6 6 30 ml/min Column Flow 36 30 ml/min Switching Flow 2 (on) 30 ml/min Switching Flow 1 (on) 36 30 ml/min Column Flow 0 ml/min Switching Flow 2 (off) Thermal Conductivity Detector (TCD) 143
Detector Systems Thermal conductivity detector (TCD) The thermal conductivity detector (TCD) detects the difference in thermal conductivity between column effluent flow (carrier gas + sample components) and a reference flow of carrier gas alone; it produces voltage proportional to this difference. The voltage then becomes the output signal to the connected chart recording or integrating device.
Detector Systems Thermal conductivity detector (TCD) Because of its exceptionally high thermal conductivity and chemical inertness, He is the recommended carrier gas: it gives large thermal conductivity differences with all compounds except H1 (considerations necessary in H1 analyses are discussed later). With He as carrier, the TCD exhibits universal response. For propane, the sensitivity limit is about 400 picograms/ml of He carrier gas.
Detector Systems Thermal conductivity detector (TCD) Optimizing performance The following sections aid in choosing operating parameters to obtain optimal TCD performance. Temperature TCD sensitivity increases as the temperature difference between the detector filament (automatically set) and the surrounding detector body (chosen detector zone temperature) increases.
Detector Systems Thermal conductivity detector (TCD) As Figure 7•9shows, however, the lower the detector zone temperature, the greater is the temperature difference between the filament versus the surrounding detector body temperature. Thus, for maximum sensitivity, the detector zone should be operated at the lowest temperature possible (limited by highest boiling components condensing inside the detector). Also, a second advantage is one of increased filament lifetime.
Detector Systems Thermal conductivity detector (TCD) Note that TCD response becomes relatively flat (insensitive) to reference gas flow rates equal to, or somewhat greater than, flow rate through the column. Analyzing for hydrogen, special considerations Only H1 has thermal conductivity greater than He. However, binary mixtures of small amounts of H1 (< 20%) in He at moderate temperatures exhibit thermal conductivities less than either component alone.
Detector Systems Thermal conductivity detector (TCD) TCD-to-FID series connection The following describes, for a TCD whose exhaust vent returns to the inside of the oven, connecting the TCD to an FID. C If necessary (see NOTE below), exchange the standard FID jet for the 0.030•inchjet (Part No. 18789•80070).Information about jet exchange is available in Chapter 8, Preventive Maintenance. Note: Use of the 0.
Detector Systems Thermal conductivity detector (TCD) filament. The immediate symptom is a permanent change in detector sensitivity due to change in filament resistance. If possible, such offending materials should be avoided. If this is not possible, the filament may have to be replaced frequently. Capillary column considerations The TCD cell filament channel has an internal volume of about 3.5 ¿l. This small cell volume makes it suitable for use with capillary columns.
Detector Systems Flame photometric detector (FPD) Flame photometric detector (FPD) Optimizing FPD sensitivity and selectivity FPD sensitivity and selectivity are affected by several important parameters. These are listed below, with suggested ways to optimize for each application. A. FPD Flow Rates. FPD flow rates are the most critical for optimizing either sensitivity or selectivity (these do not necessarily have the same optimal conditions).
Detector Systems Flame photometric detector (FPD) Figure 7-11 Pressure-psig 10 20 30 40 50 60 70 140 X } 120 X + 100 } Flow 80 ml/min 60 } 40 20 } 0X E 0 } }E X E 50 100 + X + + } = Hydrogen X+ E X = Nitrogen E = Oxygen E + = Air 150 200 250 300 350 400 450 500 Pressure-kPa FPD Flows versus Supply Pressures B. Detector Temperature. Detector heated zone temperature can have a significant effect on sensitivity.
Detector Systems Flame photometric detector (FPD) Flame ignition problems Two common flame ignition problems are: A loud pop results on ignition and the flame will not light or stay lit. If a loud pop occurs on ignition, it is usually caused by an incorrect ignition sequence. The correct ignition sequence is: 1. Open the auxiliary Nitrogen Valve if required. 2. Open the Air/Oxygen Valve fully counterclockwise (CCW). 3. Press in and hold the Ignitor Valve. 4.
Detector Systems Flame photometric detector (FPD) 3. Under some operating conditions, it is important to continue to hold the ignitor switch in for several seconds after opening the hydrogen valve fully counterclockwise. 4. Under some operating conditions, the flame may be more easily lit with the rubber drip tube removed. After lighting the flame, reinstall the drip tube and FPD cover assembly. 5.
8 Preventive Maintenance
Preventive Maintenance This chapter includes maintenance, cleaning, and leak•testingHP 5890 SERIES II (hereafter referred to as HP 5890) inlet and detector systems. Conditioning columns Columns may contain contaminants; conditioning drives off unwanted volatiles, making the column fit for analytical use. New packed columns should be conditioned since they often contain volatile contaminants absorbed from the air.
Preventive Maintenance Conditioning columns back of nut). Adjust the septum purge flow rate to no more than 6 ml/min. c. Cap inlet fittings into detector(s) to prevent entry of air and/or contaminants. 3. Establish a stable flow of carrier gas through the column. He is preferred; however, N1 is adequate for conditioning packed columns. Do not use H1 because it vents into the column oven during conditioning. a.
Preventive Maintenance (Re)Packing columns (Re)Packing columns In packing columns (particularly 1/4•inchglass columns), one must consider the type of packing, column bore, and type (metal or glass), the method of sample introduction (flash vaporization or on•column),inlet or detector base requirements. The method of sample introduction and/or the inlet/detector configuration determines the distance from the column end at which packing should start. Only general guidelines can be given here. 1.
Preventive Maintenance Packed column inlet Packed column inlet Changing septa Septum lifetime is dependent upon frequency of use and upon needle quality; burrs, sharp edges, rough surfaces, or a blunt end on the needle decreases septum lifetime. A leaking septum is evidenced by longer retention times, loss of response, and/or loss of column head pressure as well as degradation in detector signal quality (the signal becoming increasingly noisy).
Preventive Maintenance Packed column inlet Caution Column flow is interrupted while changing septa; since some columns may be damaged at elevated temperature without carrier flow, cool the oven to ambient before proceeding. WARNING Exercise care! The oven and/or inlet or detector fittings may be hot enough to cause burns. Turn off carrier flow and decrease head pressure to zero. Remove the septum retainer nut and old septum. Insert a new septum.
Preventive Maintenance Packed column inlet 4. Fully open the mass flow controller counterclockwise and wait 1 to 2 minutes to ensure equilibrium. 5. Turn off gas to the inlet at its source. 6. Wait 10 minutes while observing carrier source pressure. If it drops less than 7 to 14 kPa (1 to 2 psi), the system (through the inlet column fitting) is considered leak free. Evidence of leakage requires the inlet system be leak•checked.
Preventive Maintenance Packed column inlet Figure 8-3 Packed Column Inlet, Leak-Checking the Septum Cleaning Turn off the heated zone for the inlet and allow it to cool. Remove the septum retainer nut and septum; remove also the column and inlet liner. Using a suitable light source, illuminate the inside of the inlet from inside the oven while looking through the inlet from the top. If there is evidence of contamination or deposits, the inlet should be cleaned.
Preventive Maintenance Split/splitless capillary inlets Split/splitless capillary inlets Changing septa For a conventional disk•typeseptum, lifetime is dependent upon needle quality; needles should be sharply pointed and free of burrs or rough surfaces. Choice of septum material is less critical than with a packed column inlet since the septum is continually purged. Thus, septa can be chosen primarily for durability. Septa, 11 mm (Part No. 5181•1263,package of 25) are recommended.
Preventive Maintenance Split/splitless capillary inlets 1. Loosen and remove the septum retainer nut. Remove and discard the old septum, found either in the top of the inlet or inside the septum retainer nut. Figure 8-4 Capillary Inlet Septum Replacement, Split/Splitless and Split-Only Capillary Inlet 2. The new septum is placed in the top of the inlet base. Make sure that sealing surfaces at the top of the inlet and inside the retainer nut are clean (no particulate matter). 3.
Preventive Maintenance Split/splitless capillary inlets Leaks For proper inlet operation, it is essential the entire system be leak•tight. The following procedure should be performed in initial checkout, or any time a leak is suspected. 1. Switch off detector! 2. Install an inlet plug (a paper clip or similar•gaugewire) in the same manner as a capillary column. Figure 8-5 Capillary Inlet Plug Installed for Leak Test 3. Adjust the split•flowflow controller to about 60 ml/min. 4.
Preventive Maintenance Split/splitless capillary inlets 6. Turn off flow to the inlet by turning off carrier gas at the flow controller (fully clockwise, turning it only until it bottoms, and then no further). 7. Adjust the back pressure regulator clockwise, an additional 1/4•turn or set the electronic pressure control to 145 kPa (21 psi) and observe column pressure at the gauge for about ten minutes.
Preventive Maintenance Split/splitless capillary inlets C Use leak detection fluid to check for leakage at the column nut. If leakage is observed, try tightening the nut first. If leakage continues, replace the ferrule. Note that if the inlet is hot, leak detection fluid may boil, giving false indication of a leak. C If the septum and column nut prove to be leak•free,replace the seal (O•ring)on the inlet insert. Repressurize the system and check again for overall system leak•down.
Preventive Maintenance Split/splitless capillary inlets Figure 8-7 Solenoid Valve Assembly Solenoid Valve, Split/Splitless Capillary Inlet Cleaning Turn off the heated zone for the inlet and allow it to cool. Remove septum retainer nut, septum, insert retainer nut, and inlet insert; also remove the column. Using a suitable light source, illuminate the inside of the inlet. If there is evidence of contamination or deposits, the inlet should be cleaned.
Preventive Maintenance Liner and/or insert care Liner and/or insert care Regardless of the inlet system, inlet inserts and/or liners must be kept clean for optimum performance, particularly their interiors from which contamination may enter the column and/or interact with sample components. Note: Excessive contamination anywhere on an insert or liner should be avoided, particularly its interior. Ideally, clean replacement liners and/or inserts should be available for quick exchange when necessary.
Preventive Maintenance Liner and/or insert care Repacking a split insert Since, for a split insert, its packing material is discarded in cleaning, the insert must be repacked. Note: Repacking with small•diameterglass beads is not recommended: they are usually contaminated with metal filings due to sieving procedures used. If they must be used, thorough cleaning (chemical and physical) is required. C Use a fresh, small amount of a conventional coated packing such as 2% OV•1on 100/120 mesh, Chromosorb W•HP.
Preventive Maintenance Flame ionization detector (FID) Metal inserts and/or liners C Do not use concentrated acid(s) on metal inserts or liners! C The insert is washed with noncorrosive solvents (H1O, CH2OH (methanol), (CH2)1CO (acetone), CH1Cl1 (methylene chloride), etc), and then dried thoroughly in an oven at 105^C.
Preventive Maintenance Flame ionization detector (FID) Jet exchange/replacement Depending upon the column type to be used, and/or analyses to be performed, exchanging the jet in an FID may be necessary. Figure 8-9 Flame Ionization Detector Note: The proper jet must be installed prior to column installation. If switching from packed column operation to capillary operation, the jet for capillary use must be installed prior to column installation.
Preventive Maintenance Flame ionization detector (FID) Table 8-1. Available FID/NPD Jets Part No. Jet Tip ID (inch)* Use 18789-80070 0.030 Packed Column Only (FID only: Simulated Distillation, TCD-to-FID series operation) 18710-20119 0.018 Packed Column (Standard, FID and NPD) 19244-80560 0.011 Capillary Column (FID and NPD) (FID: high sensitivity, packed column) * Measured at the jet tip. NOTE: The 0.011-inch jet optimizes performance with capillary columns.
Preventive Maintenance Flame ionization detector (FID) Figure 8-10 Collector Assembly Cover Removed, Flame Ionization Detector (FID) Turn off the detector and its heated zone; also turn off gases to the detector (particularly H1!). Allow time for the detector zone to cool. Open the top cover at its front edge to access the detector. 1. Using a Pozidriv•typescrewdriver, remove three screws around the detector cover, and remove the cover. 2. Remove the FID collector assembly by pulling it straight up. 3.
Preventive Maintenance Flame ionization detector (FID) Wash the collector in distilled water, hexane, and/or CH2OH (methanol). Dry in an oven at 70^C for at least 1/2•hour. Figure 8-11 FID Collector Assembly 4. Using a 1/4•inchhex nut driver, unscrew (counterclockwise) and remove the jet from the detector base.
Preventive Maintenance Flame ionization detector (FID) Figure 8-12 Je t FID Jet 5. The jet exists in three sizes: 0.030•,0.018•,or 0.011•inch.Use a cleaning wire (0.016•inchod, 12•inchlength, Part No. 18765•20070)to loosen/remove internal deposits. Be careful in using the wire with the 0.011•inchjet. Wash both the internal bore and exterior of the jet with a 1:1 (V/V) solution of CH2OH (methanol) and (CH2)1CO (acetone). 6. Clean the detector base cavity using solvents, a swab, and compressed air or N1.
Preventive Maintenance Flame ionization detector (FID) Figure 8-13 Sprin g Interconnect FID Signal Board Interconnect 9. Reassemble the detector cover. Ignition problems Before proceeding, make sure that gases are plumbed correctly, the system is leak•free,flow rates are set correctly, and external lines have been well purged. Note: If Helium is being used as carrier/makeup gas, be aware that flame lighting problems may occur at very high flow rates ( > 50 ml/min).
Preventive Maintenance Nitrogen-phosphorus detector (NPD) is best to have a new jet on hand to exchange if a damaged jet is suspected. Nitrogen-phosphorus detector (NPD) In addition to the detector itself, other systems associated with the detector may also require routine maintenance. WARNING Nitrogen•phosphorusdetectors use H2 gas as fuel. If H2 flow is on, and no column is connected to the detector inlet fitting, H2 gas can flow into the oven and create an explosion hazard.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) Turn off the detector and its heated zone; also turn off gases to the detector (particularly H1! ). Allow time for the detector zone to cool. Open the top cover at its front edge to access the detector. 1. Using a Pozidriv•typescrewdriver, remove three screws around the detector cover and carefully remove the cover (see Caution below). Note that the transformer supplying power to the active element is secured to the inside of the cover.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) 2. a. Using compressed air or N1, blow out loose material from inside the collector. Do this carefully so as not to disturb the active element. Caution Do not attempt to clean the inside of the collector by inserting objects such as wires or brushes; to do so may damage the active element. b. Wash the collector in hexane or isooctane. Then carefully dry the collector using compressed air or N1.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) Caution Do not overtighten the jet! Overtightening may permanently deform and damage the jet, the detector base, or both. 8. Replace the NPD collector, and transformer and cover assembly. Be certain the spring contact to the signal board is in good contact with the groove on the collector (see Figure 8•13).
Preventive Maintenance Nitrogen-phosphorus detector (NPD) Figure 8-17 Type A Type B Detector Cover Transformer Brass Collar Teflon Spacer Transformer Strap Steel Spring Spacer Collector O-ring Collector Body NPD Collector and Collector Assembly Whenever the collector must be removed from the detector cover of a Type A NPD, the following procedure should be used: Note: During disassembly do not touch the lower portion of the collector assembly.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) 3. Remove the Teflon spacer and stainless steel spring spacer from the top of the collector body. 4. Loosen the setscrew in the Teflon portion of the collector body. 5. Grasping the collector at its top end (to avoid contaminating its detecting end), withdraw it from the collector body. Some resistance to this occurs until the O•ringseal becomes free. 6.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) lead on the collector body. Tighten the setscrew to secure the wire and collar. Type B NPD transformer/collector assembly Figure 8-18. Type B NPD Detector Assembly Remove the transformer/collector assembly from the Type B NPD cover as follows: Caution During disassembly do not touch the lower portion of the collector assembly. Use clean, lint•freegloves to prevent contamination of the assembly. Suitable gloves (HP Part No.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) 4. Remove the collector from the collector assembly as follows: C Loosen the 1.5•mmscrew holding the transformer secondary wire to the top of the collector and disconnect the wire. The hex key wrench required is a 1.5•mmsize and was provided with the instrument. C Loosen the 1.5 hex key screw holding the brass connector to the collector top and remove the brass connector.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) Reinstallation 1. Reinstall the jet in the detector base (using a 1/4•inchnut driver). Make sure that the threads are clean and free of burrs that could cause damage. If there is any binding, the cause should be determined and corrected before proceeding. If a torque wrench is available, no more than 1 Nm (newton meter) of torque should be used to install a new jet.
Preventive Maintenance Nitrogen-phosphorus detector (NPD) C All collectors should be washed off with GE grade hexane or a similar solvent before reinstalling in the instrument to remove any grease, fingerprints, or other contaminants. Soak the entire collector in a vial of hexane for several minutes (2-10). Remove the collector, touching only the top portion, and scrub the lower, outer collector tube with a clean wipe soaked with hexane. Dry off the excess hexane solvent.
Preventive Maintenance Electron capture detector (ECD) Electron capture detector (ECD) Frequency test Note: For high sensitivity operation, and starting from a cold system, 24 hours may be necessary before baseline is completely stabilized. Use low•bleedsepta and condition a new septum prior to use in an unused inlet for several hours with 1 to 5 ml/min carrier flow rate.
Preventive Maintenance Electron capture detector (ECD) remove the column to the ECD. If a capillary column was installed, remove also the makeup gas adapter in the detector base. 2. Disconnect the carrier gas source line at its fitting on the HP 5890. 3. Using a Vespel ferrule, and adapters as necessary, connect the carrier source line to the detector base, including any traps in the line. 4. Set carrier pressure to about 7 kPa (1 psi) and check for flow through the detector. 5.
Preventive Maintenance Electron capture detector (ECD) flow through the system is available. Allow time for the system to become fully pressurized. 4. Close carrier gas flow at its source and monitor system pressure. 5. The system may be assumed to be leak•freeif no pressure drop is observed over a 10•minuteperiod. 6. If leakage is observed, use an appropriate leak•detectingfluid to check for leaks at detector column fittings and at the plugged vent. 7.
Preventive Maintenance Electron capture detector (ECD) Packed column: 1. Close the anode purge on/off valve. 2. Remove the column from the detector; install in its place an empty glass column. 3. Establish normal carrier gas flow rate (20 to 30 ml/min); set oven temperature to 250^C. 4. Open the anode purge on/off valve. 5. Heat the ECD to 350^C. Allow thermal cleaning to continue for 3 to 12 hours.
Preventive Maintenance Thermal conductivity detector (TCD) Radioactivity leak test (wipe test) ECDs must be tested for radioactive leakage at least every six months. Records of tests and results must be maintained for possible inspection by the Nuclear Regulatory Commission and/or responsible state agency. More frequent tests may be conducted when necessary. The procedure used is the wipe test. A wipe test kit (Part No. 18713•60050)is supplied with each new ECD.
Preventive Maintenance Flame photometric detector Caution Failure to turn off the TCD and to cap the detector column fitting may cause irreparable damage to the filament due to O2 entering the detector. 3. Establish normal reference gas flow rate (20 to 30 ml/min) through the detector (set oven temperature to 250^C). 4. Heat the detector to 400^C; allow thermal cleaning to continue for several hours.
Preventive Maintenance Flame photometric detector Likewise, damage to the PMT window cannot be tolerated; if necessary, replace the PMT or call Hewlett•Packardsupport. 1. Remove four screws to remove the PMT adapter flange. Remove the adapter carefully; a quartz window is exposed and may fall out. The window is cleaned in a manner similar to the filter. 2. Remove four more screws to remove the stainless steel coupling. Remove the coupling carefully; the remaining quartz window may fall out.
Preventive Maintenance Flame photometric detector Figure 8-20.
Preventive Maintenance Flame photometric detector Figure 8-21.
Preventive Maintenance Flame photometric detector NOTE: Once installed, the ferrule cannot be removed from the liner for reuse unless both parts are still warm. Cleaning/replacing the FPD jet If a response problem is encountered (sensitivity, noise, selectivity), the FPD jet should be inspected for deposits and, if necessary, cleaned or replaced. To service the jet properly, the detector module should be removed from the instrument, followed by appropriate service: 1.
Preventive Maintenance Flame photometric detector 6. Use compressed gas, air, or N2 to blow out loose particles from the jet and/or detector module body. 7. Inspect and clean deposits from the jet bore and from the threads using a suitable wire. If the jet is damaged in any way, it should be replaced. It is good practice to replace the jet rather than cleaning it, particularly when extremely high sensitivity is required. 8. A new Kalrez O•ringseal (Part No.
Preventive Maintenance Flame photometric detector this indicates a leak in the system. Begin checking possible leak sources and monitor the EFS to determine when the leak has been eliminated. Possible leak sources, in order of probability are: 1. septum 2. column fittings 3. supply line swage•typeplumbing connections 4. detector block O•ringor Vespel seals 5.
Preventive Maintenance Conditioning chemical traps Conditioning chemical traps Remove the trap from its installed location and attach it to a clean, dry gas source (helium or nitrogen). Attach the 1/8•inchend (male) of the chemical trap assembly to the reconditioning gas source using a graphite or a graphitized Vespel ferrule (Part No. 0100-1 107) and swage nut (Part No. 0100-0058), as metal type ferrules will damage the sealing surface of the 1/8•inchadapter. Remove the O•ring(Part No.
9 Chromatographic Troubleshooting
Chromatographic Troubleshooting Introduction This chapter is concerned with diagnosis: the process of going from unexpected behavior of the HP 5890 SERIES II (hereafter referred to as HP 5890) (symptoms) to the probable location of the difficulty (causes). Problems arise from many causes.
Chromatographic Troubleshooting Baseline symptoms C It can also result from valve operations: If valves are being switched during a run, examine the valve time program to see if the change coincides with a valve operation. C This symptom also can occur if the septum suddenly begins to leak; Avoid the problem by changing septa regularly. C Offset•see troubleshooting procedure for the particular detector in use.
Chromatographic Troubleshooting Baseline symptoms 2. Baseline is erratic, moves up and down (wander): C Suspect a leak in the system: Check septum condition and replace if necessary. Check column connections. If the leak is at the detector end of the column, retention times are stable from run to run, but sensitivity is reduced. If it is at the inlet end, sensitivity is reduced and retention times are delayed.
Chromatographic Troubleshooting Baseline symptoms C Contaminated detector gases (hydrogen and air). C Air currents from a fan or air conditioner blowing across the top of the instrument may interfere with gas exiting from the detector. This is a possible, though not very likely, cause of noise since detectors are well protected. Switching off the air current source or shielding the detector area identifies this problem. C An inadequately tightened collector on an FID or NPD generates noise.
Chromatographic Troubleshooting Baseline symptoms Spiking Spikes are isolated baseline disturbances, usually as sudden (and large) upscale movements. If accompanied by noise, the noise problem should be solved first, since spiking may disappear at the same time. 1. Spikes appear whenever the chart is running: C The cause is almost always electronic in origin: Loose connections are likely. Check signal cable connections at the detector and controller ends.
Chromatographic Troubleshooting Retention time symptoms Retention time symptoms Retention time drift Retention time drift is a steady increase or decrease of retention times in successive runs. Erratic times (both directions) are discussed below as retention time wander. 1. In a series of runs, retention times suddenly increase: C This may be due to an oven temperature change or to change in flow; verify setpoints. C A blown septum is a possibility.
Chromatographic Troubleshooting Retention time symptoms 2. Reproducibility is good early in the run but not toward the end: C This may occur in temperature•programminga very densely packed column; as column contents expand with heating, resistance to flow may be so great that a mass flow controller cannot maintain constant flow. Try increasing carrier source pressure. If this is the cause, the problem will either vanish or its onset will move later in the run.
Chromatographic Troubleshooting Peak symptoms Peak symptoms No peaks This is usually due to operator error; possibilities include injection on the wrong column, incorrect signal assignment, attenuation too high (peaks are present but not visible), a bent syringe needle in an automatic sampler, etc. Check system parameters for the analysis. Inverted peaks This is likely an inappropriate signal assignment definition (e.g., B - A with sample injected on column A) or incorrect polarity with a TCD.
Chromatographic Troubleshooting Peak symptoms stationary phase with trace levels of O1, H1O, and/or other materials present in the carrier gas. C A contaminated inlet may also produce ghost peaks. Residues in the inlet are volatilized or pyrolyzed and swept onto the head of the column. Try reducing inlet temperature; if this eliminates or reduces ghosts, the inlet should be cleaned. 2. Additional peaks appear when pure sample is injected: C These might be ghost peaks as described above.
Chromatographic Troubleshooting Peak symptoms Deformed peaks The ideal peak, rarely occurring in chromatography, is a pure Gaussian shape. In practice, some asymmetry is always present, particularly near the baseline. 1. The peak rises normally, then drops sharply to baseline: Figure 9-1. Overloaded Peak C The most likely cause is column overload; dilute the sample ten•foldand run it again.
Chromatographic Troubleshooting Peak symptoms C Interaction with column material is a frequent cause. Silanized support may help. An all•glasssystem may be required if metal column tubing is the source. C Column overload with a gas sample often shows this effect; try injecting less. C This may be a merged peak situation: Running at lower (30^C) oven temperature will increase resolution, perhaps enough to reveal merged peaks. C Low inlet temperature may cause this, as can poor injection technique. 3.
Chromatographic Troubleshooting Peak symptoms 4. Top (apex) of the peak is split: Figure 9-4. FID/NPD Flameout, or TCD with H1 (in He Carrier) C Verify that this is not a merged peak situation: Reduce oven temperature 30^C and repeat the run. If the split peak becomes better resolved, it is probably a merged pair. C Gross overload of an FID may cause the top of the peak to invert, giving appearance of a split peak. Check gas flows; overload is more likely when flows are too low.
Chromatographic Troubleshooting Troubleshooting valve systems Troubleshooting valve systems Chromatographic symptoms Troubleshooting valves and their related plumbing is primarily a matter of systematic checking and verification of unimpaired mechanical operation of any moving part. This requires an understanding of how the valve functions internally and how the plumbing is configured. A plumbing diagram is essential for effective troubleshooting.
Chromatographic Troubleshooting Troubleshooting valve systems Loss of peaks in specific areas of the chromatogram Entire sections of chromatographic data can be lost due to a valve that does not rotate or one that rotates improperly. Other than obvious component failures (i.e., solenoid, actuator, etc.), generally improper adjustments and misalignments cause most problems. C Check that adequate air (about 482 kPa or 70 psi) is supplied. C Check if the valve is rotating at all.
Chromatographic Troubleshooting Locating leaks Extraneous peaks Air peaks are sometimes seen in a chromatogram when leakage occurs because the valve rotor does not seal properly. These leaks may not be detectable by using the soap•bubblemethod. The leak test procedure is described in the Site Prep and Installation Manual. If a leak is suspected but cannot be located with soap bubbles, a pressure check will determine definitely if a leak exists.
Chromatographic Troubleshooting Pressure check Pressure check The pressure•checkmethod will indicate, but sometimes not isolate, a leak in the flow path. Since this method does not necessarily isolate the leak, one of the leak•checkmethods may be needed to locate the leak specifically. Note that each valve in a system has two flow paths, on and off. A leak sometimes occurs in only one of these two positions. Check both. 1. Disconnect the detector from the valve system. 2.
Chromatographic Troubleshooting Electronic pressure control Electronic pressure control The electronic pressure control option provides very accurate and precise control of column head pressure, resulting in retention time reproducibility of better than 0.02% RSD when there are no column effects. The inlet pressure can be set constant, programmed, or set to maintain a desired column flow rate. This mass flow control can be maintained even at vacuum column outlet pressures.
Chromatographic Troubleshooting Electronic pressure control Safety shutdown Systems equipped with electronic pressure programming have a safety shutdown feature to prevent gas leaks from creating a safety hazard. If the system cannot reach a pressure setpoint it beeps. After about 45 seconds the beep will stop and the message: ACTUAL SETPOINT EPPB: SAFETY SHUTDOWN will appear on the display, and the system will shut down by turning off all electronic pressure and heated zones, and locking the keyboard.
Chromatographic Troubleshooting Electronic pressure control Proper configuration If the inlet is not working at all, there may be a configuration problem. 1. Turn GC power off, and remove the side panel of the GC. 2. Check if the red switches on the inlet controller board are set for your configuration. 3. Turn the GC on.
Chromatographic Troubleshooting Electronic pressure control Switch setting examples IN A1 or IN B1 RIGHT, currently unused PID IN A0 or IN B0 LEFT, Programmable Cool On-Column (PID) / RIGHT, Purged Packed Inlet & Split/Splitless Capillary Inlet (PID) LEFT, (FPR) Programmable Cool On-Column Inlet & Purged Packed Inlet / RIGHT, (BPR) Split/Splitless Capillary Inlet MODE A or MODE B EPC A or EPC B LEFT, Electronic Pressure Control present / RIGHT, Electronic Pressure Control not present EXAMPLE INLET
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10 Test Sample Chromatograms
Test Sample Chromatograms This chapter contains typical examples of test sample chromatograms. They may be used as a general guide to instrument performance. It is assumed that both the instrument and proper test column are installed, that general keyboard control is understood (temperature control, defining signal output, etc.), and that specific operating information for the given inlet and detector is also understood.
Test Sample Chromatograms Test sample chromatograms Test sample chromatograms Figure 10-1. HP 5890 Test Sample Operating Conditions Detector Type FID (or FIDw/MUG) Temp 250 DEGREES C Inlet Type PACKED (OR PURGED PACKED). Temp 200 DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Programmed (1 ramp) Init Temp 110 DEGREES C Init Time 0 min Ramp Rate 15 Fin Temp 150 Fin Time 1 Range 8 COLUMN: Part No.
Test Sample Chromatograms Test sample chromatograms Figure 10-2. HP 5890 Test Sample Operating Conditions Detector Type NPD (or NPDw/MUG) Temp 220 DEGREES C Inlet Type PACKED (OR PURGED PACKED). Temp 170 DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Isothermal Init Temp 170 DEGREES C Init Time 3.0 min Ramp Rate 0 Fin Temp Fin Time Range 0 COLUMN: Part No. Dimensions Sta Phase FLOW RATES Carrier (He) 20 +/• 1 Hydrogen 3.5 +/• 0.
Test Sample Chromatograms Test sample chromatograms Figure 10-3. HP 5890 Test Sample Operating Conditions Detector Type ECD(or ECDw/MUG) Temp 300 DEGREES C Inlet Type PACKED (OR PURGED PACKED). Temp 200 DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Isothermal Init Temp 160 DEGREES C Init Time N/A min Ramp Rate 0 Fin Temp Fin Time Range 2 COLUMN: Part No.
Test Sample Chromatograms Test sample chromatograms Figure 10-4. HP 5890 Test Sample Operating Conditions Detector Type TCD(or TCDw/MUG) Temp 300 DEGREES C Inlet Type PACKED (OR PURGED PACKED). Temp 250 DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Programmed (1 ramp) Init Temp 110 DEGREES C Init Time 1 min Ramp Rate 15 Fin Temp 150 Fin Time 1 Range 0 COLUMN: Part No.
Test Sample Chromatograms Test sample chromatograms Figure 10-5. HP 5890 Test Sample Operating Conditions FLOW RATES Detector Type FIDw/MUG Carrier (He) 15 +/• 1 ml/min Temp 250 DEGREES C Hydrogen 30 +/• 1 ml/min Inlet Type Ded On-Col Cap Air 400 +/• 20 ml/min Oven Track On Makeup (N2) 20 +/• 1 ml/min Temp N/A C Split Vent N/A ml/min Operating Mode N/A Septum Purge 5 +/• 1 ml/min Purge Time On N/A min Purge Time Off N/A min Oven Temp Temp Programmed (1 ramp) Init Temp 60 DEGREES C min Init Time 0.
Test Sample Chromatograms Test sample chromatograms Figure 10-6.
Test Sample Chromatograms Test sample chromatograms Figure 10-7. HP 5890 Test Sample Operating Conditions Detector Type NPD w/MUG Temp 220 DEGREES C Inlet Type Split only or split/splitless Temp 200 DEGREES C Operating Mode Split(Purge on) Purge Time On 0 min Purge Time Off 0 min Oven Isothermal Init Temp 180 DEGREES C Init Time 5.0 min Ramp Rate 0 Fin Temp Fin Time Range 0 COLUMN: Part No. Dimensions Sta Phase FLOW RATES Carrier (He) 15 +/• 1 Hydrogen 3.5 +/• 0.
Test Sample Chromatograms Test sample chromatograms Figure 10-8. HP 5890 Test Sample Operating Conditions Detector Type ECDw/MUG Temp 300 DEGREES C Inlet Type Split only or splitless Temp 200 DEGREES C Operating Mode Split(Purge on) Purge Time On 0 min Purge Time Off 0 min Oven Temp Isothermal Init Temp 170 DEGREES C Init Time N/A min Ramp Rate 0 Fin Temp Fin Time Range 0 COLUMN: Part No.
Test Sample Chromatograms Test sample chromatograms Figure 10-9.
Test Sample Chromatograms Test sample chromatograms Figure 10-10. HP 5890 Test Sample Operating Conditions Detector Type NPD w/MUG) Temp 220 DEGREES C Inlet Type Ded On-Col Cap Oven Track On Temp N/A C Operating Mode N/A Purge Time On min Purge Time Off min Oven Isothermal Init Temp 170 DEGREES C Init Time 5.
Test Sample Chromatograms Test sample chromatograms Figure 10-11. HP 5890 Test Sample Conditions Detector Type TCDw/MUG Temp 300 DEGREES C Inlet Type Ded On-Col Oven Track On Temp N/A C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Programmed (1 ramp) Init Temp 60 DEGREES C Init Time 0.5 min Ramp Rate 20 Fin Temp 180 Fin Time 1 Flow Param (EPP) Constant Flow Off Range 0 COLUMN: Part No.
Test Sample Chromatograms Test sample chromatograms Figure 10-12.
Test Sample Chromatograms Test sample chromatograms Figure 10-13. HP 5890 Test Sample Operating Conditions Detector Type FPD Temp 200 DEGREES C Inlet Type PACKED OR PURGED PACKED Temp 200 DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Programmed (1 ramp) Init Temp 110 DEGREES C Init Time 0 min Ramp Rate ___10 Fin Temp __170 Fin Time ____3 Range 5 COLUMN: Part No. 19095S•100 Dimensions 5 M Length, 530 ¿ ID Sta Phase Methyl Silicone START IF.
Test Sample Chromatograms Test sample chromatograms Figure 10-14. HP 5890 Test Sample Operating Conditions Detector Type FPD Temp 200 DEGREES C Inlet Type SPLIT ONLY OR SPLIT/SPLITLESS Temp 200 DEGREES C Operating Mode SPLIT(PURGE ON) Purge Time On 0 min Purge Time Off 0 min Oven Temp Programmed (1 ramp) Init Temp 110 DEGREES C Init Time 0 min Ramp Rate ___10 Fin Temp _ 170 Fin Time ____3 Range 5 COLUMN: Part No. 19095Z•121 Dimensions 5 M Length, 530 ¿ ID Sta Phase Methyl Silicone START IF .11 .
Test Sample Chromatograms Test sample chromatograms Figure 10-15. HP 5890 Test Sample Operating Conditions Detector Type FPD Temp 200 DEGREES C Inlet Type DED ON-COL CAP Oven Track On Temp N/A DEGREES C Operating Mode N/A Purge Time On N/A min Purge Time Off N/A min Oven Temp Programmed (1 ramp) Init Temp 90 DEGREES C Init Time 1.0 min Ramp (1) (2) Rate 20 10 Fin Temp 110 170 Fin Time 0 3 Flow Param (EPP) Constant Flow Off Range 5 COLUMN: Part No.
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Index A adapters, 17 detector, 22 ECD, 23 installation, 24 TCD, 23 alphanumeric display, 33 B baseline problems noise, 204 position, 202 spiking, 206 wander and drift, 203 C calibration electronic flow sensor, 60 oven temperature, 54 capillary columns, metal, 30 clear dot function, 39 cold trapping, 116 collector replacing NPD, 181 type B NPD, 184 column adapters, 17 bracket, 14 capillary, 13 conditioning, 156 ferrules, 14 fittings, 14 inserts, 17 liners, 17 nuts, 14 o-rings, 14 packed, 12 packing, 158 p
Index electronic flow sensor (EFS) calibration, 60 packed inlet, 102, 106 electronic pressure control troubleshooting, 218 entering setpoints, 34 F fault: messages, 52 ferrules, 14 FID, 171 ignition problems, 177 jet replacement, 30, 172, 173 on•columntest chromatogram, 229 split inlet test chromatogram, 230 test chromatogram, 225 FID flameout problems, 128 fittings, 14 flash back, 117 flow sensing, 58 FPD, 193 cleaning/replacing jet, 197 cleaning/replacing windows, filters, seals, 193 leak testing with E
Index L leaks ECD, 189 FPD with EFS, 198 FPD without EFS, 199 packed column inlet, 160 pressure checking, 217 split/splitless capillary inlet, 165 valves, 216 O o-rings, 14 oven, 11 isothermal, 49 programming temperature, 49, 117 safety, 51 status, 50 temperature calibration, 54 LED display, 33 P lighting problems, FID, 177 liners, 17 care of, 169 detector, 22 installation, 24 metal, 171 packed column inlet, 100, 159 changing septum, 159 cleaning, 162 leaks, 160 lock keyboard, 38 peak problems defor
Index S septum, changing packed column inlet, 159 split/splitless capillary inlet, 163 septum purge, packed inlet, 105 septum purged packed column inlet, 103 setpoint protection, 38 setpoints displaying, 33 entering, 34 ranges, 46 solvent effect, 114 T TCD, 192 cleaning, 192 on•columntest chromatogram, 235 split inlet test chromatogram, 233 test chromatogram, 228 temperature control, 44 temperature programming, oven, 49 test chromatograms, 224 troubleshooting, 202 troubleshooting electronic pressure contr
