SenTix® 950 SenTix® 980 pH combination electrodes with refillable liquid reference system Operating manual ba75843e01 08/2009
SenTix Note The latest version of the present operating manual can be found on the Internet under www.WTW.com. Copyright © Weilheim 2009, WTW GmbH Reprinting - even as excerpts - is only allowed with the explicit written authorization of WTW GmbH, Weilheim. Printed in Germany.
SenTix General information General information Automatic sensor recognition The sensor electronics with the stored sensor data is in the connecting head of the electrode. The data include, among other things, the sensor type and series number. With each calibration, the calibration data is written in the sensor and the calibration history is recorded. The data is recalled by the meter when the sensor is connected and is used for measurement and for measured value documentation.
Technical data SenTix Technical data General data WTW model ® SenTix 950 ® SenTix 980 Reference electrolyte + KCl 3 mol/L, Ag free KCl 3 mol/L, Ag+ free Junction NTC Special features Ceramic Yes Plastic shaft Platinum Yes Measurement and application characteristics WTW model pH measuring range Allowed temperature range SenTix® 950 0.000 ... 14.000 0 ... 80 °C (32 ... 176 °F) SenTix® 0.000 ... 14.000 0 ... 100 °C (32 ...
SenTix Commissioning, measuring, calibration Commissioning, measuring, calibration Commissioning The electrode is filled with reference electrolyte solution in the factory. Prepare the electrode for measuring as follows: z Open the refilling opening for the reference electrolyte solution. Depending on the model, the stopper of the refilling opening is an elastomer stopper or a slider.
Storage SenTix trolyte in the electrode must be at least 2 cm above the level of the solution. Shaft Reference electrolyte Junction (Example) Glass membrane z Provide approximately the same stirring conditions for measuring as for calibrating. Note Prevent contact of the pH membrane to the beaker bottom to avoid scratches on the pH membrane. Subsequent calibrations The frequency of subsequent calibrations depends on the application.
SenTix Aging Note During longer storing periods, salt sediments may develop on the watering cap. They do not affect the measuring characteristics and can easily be removed with deionized water when the electrode is put into operation again. Aging Every pH electrode undergoes a natural aging process. With aging, the responding behavior becomes slower and the electrode slope and asymmetry change. Moreover, extreme operating conditions can considerably shorten the lifetime of the electrode.
Maintenance and cleaning Cleaning SenTix Remove water-soluble contamination by rinsing with deionized water. Remove other contamination as follows: Contamination Cleaning procedure Fat and oil Rinse with water containing household washing-up liquid Lime and hydroxide deposits Rinse with citric acid (10 % by weight) Proteins Immerse in pepsin cleaning solution PEP/pH for approx. 1 hour. Note: Make sure the level of the reference electrolyte is above that of the cleaning solution.
SenTix Wear parts and accessories Wear parts and accessories Description Model Order no. Reference electrolyte solution 250 mL (KCl 3 mol/L, Ag+ free) KCl-250 109 705 Pepsin cleaning solution 3 x 250 ml PEP/pH 109 648 Note Detailed information on our wide range of buffer solutions and more accessories is given in the price list of the WTW catalog "Laboratory and field instrumentation".
Disposal 20 SenTix ba75843e01 08/2009
