HI 4111 IODIDE COMBINATION IODIDE HI 4011 Instruction Manual HI 4011 HI 4111 Half-cell Combination Iodide Ion Selective Electrode 1
HI 4011 Iodide Half-cell HI 4111 Iodide Combination Electrode I. Introduction: The Hanna HI 4011 and HI 4111 are ion selective electrodes designed for the measurement of Iodide ions in aqueous solutions. The HI 4011 is a solid state half-cell sensor that requires a separate reference. The HI 4111 is a combination ion selective electrode. IIII. Specifications Type: Solid State electrode with a Silver Iodide pellet. - Ion(s) measured: Iodide (I- ) Measurement range: 1.0 M to 1 X 10-7M 127,000 to 0.
III. Theory of Operation Operation:: The HI 4011 or HI 4111 Iodide electrodes are potentiometric devices used for the rapid determination of free Iodide ions in food products, plants, and as an indicator in titrations. The electrode functions as a sensor or ionic conductor. The HI 4011 requires a separate reference electrode to complete its electrolytic circuit. The HI 4111 incorporates a reference electrode.
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V. Equipment required: • Hanna HI 5315 Double Junction Reference Electrode with HI 7072 Fill Solution for HI 4011. • Hanna HI 4222 pH/ISE/mV meter or other suitable ion or pH/mV meter. (Note: log/linear graph paper is useful if an ISE (ion) meter is not available). • Hanna HI 180 Magnetic Stirrer or equivalent with TFE coated stirring bars (HI 731320). Note: isolate beakers from stirrer motor heat by placing insulating material such as foam or cork between them.
VII VII. General Guidelines • Calibration standards and sample solutions should have the same ionic strength. ISA should be added to both samples and standards in the same ratio. 1 part ISA to 50 parts standard is the normal dosing. • Concentrated samples (>1 M) should be diluted before measurement. Multiply the final result by the corresponding dilution factor.
HI 4011 • Remove protective cover from sensor tip. • Prepare HI 5315 reference electrode by filling electrolyte reservoir with HI 7072 fill solution. • Place sensor and reference electrodes into electrode holder and connect cable connectors to meter. HI 4111 • Remove the protective plastic wrap that covers the ceramic junction before assembling sensor for the first time. • HI 7072 reference fill solution should be added daily to electrolyte reservoir before electrode use.
Deionized Water VIII. Electrode Preparation HI 4011 1. Remove protective cover from sensor tip. 2. Prepare reference electrode by filling outer electrolyte reservoir with HI 7072. 3. Place sensor and reference electrodes into electrode holder and connect cable connectors to meter. HI 4111 1. Unwrap plastic film seal found over ceramic junction on inner stem and discard. This is only used for shipping and long term storage. 2.
HI 4111 IODIDE TION NA COMBI 6. Holding the body of the electrode gently press upper cap with your thumb. This permits the fill solution to drain out of the body. Release cap and verify electrode returns to its original position. (You may need to gently assist for this to occur). 7. Tighten the electrode cap onto the body and fill electrode body until fill solution volume is just below fill hole. 8. Position electrode in a Hanna HI 76404 electrode holder (or equivalent) and connect plug to meter.
IX. • • • • • • • Quick Check of Electrode Slope Connect sensors to pH/mV/ISE meter Place meter in mV mode. Place 100 mL of DIW into a beaker with stir bar. Place electrodes into prepared sample. Add 1 mL of a standard 0.1 M (12690 ppm) standard to beaker. Record the mV value when stable. Add an additional 10 mL of standard to the solution. Record the mV when reading has stabilized. This value should be less than the previous noted (more negative). Determine the difference between the two mV values.
• If the membrane is damaged, the response becomes extremely sluggish, or the slope of the electrode has decreased significantly, and procedures above have not helped, the sensor should be replaced. XI. Direct Calibration and Measurement This method is a simple procedure for measuring many samples. A direct reading ISE meter (HI 4222 or equivalent) determines concentration of the unknown by a direct reading after calibrating the meter with the standards.
Procedure Follow sections VIII and IX to prepare sensors for measurement. Follow section VI to prepare standards / solution. Standards should bracket and fall within the range of interest. Two mL HI 4000-00 ISA is added to 100 mL of both samples and standards Add stir bar and mix before taking measurements. Follow section VII; General Guidelines to optimize test set-up. During calibration it is best to start with lower concentration samples first. Wait for a stable measurement before recording values.
XII. Other Measurement TTechniques echniques Known Addition (for I ) An unknown concentration can be determined by adding a known amount (volume and concentration) of measured ion to a known volume of the sample. This technique is called Known Addition. The method can use an ideal sensor slope, but actual determined slopes at the temperature of measurement should be used if known. The volume and concentration of the added standard must cause a mV change of at least 30 mV.
Titration An iodide electrode may be used as an indicator to follow the progress and detect the endpoint of a titration of iodide containing samples with silver nitrate. The electrode can be used in colored samples, or high or variable ionic strength samples to increase accuracy of the determination. During the titration the sensor follows the decrease in Iodide concentration while small additions of silver nitrate titrant are added.
XV ables XV.. Conversion TTables For I- Multiply by Moles/L (M) to ppm (mg/L) ppm (mg/L) to M (moles/L) 1.269 x 105 7.
MAN4111 02/07R1 WARRANTY Hanna Instruments Ion Selective Electrodes are warranted to be free of defects in material and workmanship for 6 months from date of purchase when used for their intended purpose and maintained according to instructions. If they fail to work when first used contact your dealer immediately. Damage due to accidents, misuse, misapplication, tampering or lack of prescribed maintenance is not covered.
