one、overview：The pH composite electrode is made of low impedance sensitive glass film and can be applied to pH measurement under various conditions. It has the characteristics of fast response and good thermal stability: it has good reproducibility, is not easy to hydrolyze, and basically eliminates alkali errors. It shows a good performance in the range of 0-14PHLinear power value, The reference system composed of Ag/Agcl and gel electrolyte salt bridge has stable half cell potential and excellent anti pollution performance. The circular polytetrafluoroethylene diaphragm is not easy to block and can be detected online for a long time

two、 Main technical parameters

Measurement range:0-14PH measurement accuracy: ≤ 0.01PH

responsiveness: 5secThe equipotential point of the electrode: 7±0.5PH

three 、use and maintenance

The electrode must be calibrated with a standard buffer solution with a known pH value before measurement. To improve measurement accuracy, the pH value of the buffer solution should be reliable, and the closer it is to the measured value, the better, generally not exceeding three PH.

The sensitive glass bulb at the front end of the electrode should not come into contact with hard objects, as any damage or scratching will cause the electrode to fail.

The 3-electrode wiring must be kept highly clean and dry. If there is any contamination, it can be wiped clean with medical cotton and anhydrous alcohol and blown dry to absolutely prevent short circuits at the output terminals, otherwise it will cause measurement errors or failures.

When measuring, the electrode should be stirred in the test solution and placed still to accelerate the response

Before and after the measurement, the electrode should be cleaned with deionized water to ensure measurement accuracy. After measuring in viscous samples, the electrode needs to be washed with deionized water to remove the solvent

After long-term use, the electrode will become passivated due to low sensitivity gradient, slow response, and inaccurate readings. At this time, the bottom bulb of the electrode can be soaked in a 0.1M solution for 24 hours (0.1M dilute hydrochloric acid preparation: 9ml hydrochloric acid is diluted to 1000ml with distilled water), and then soaked in a 3Mkcl solution for several hours to restore its performance

7 Glass bulb contamination or liquid interface blockage can also cause electrode passivation. At this time, appropriate solution cleaning should be carried out according to the properties of the pollutant, as shown in the table below (for reference)

pollutantInorganic metal oxidesdetergent: Less than 1M dilute hydrochloric acid

Organic oils and fats Dilute detergent(Weakly alkaline)

Resin polymer materialDilute alcoholAcetone, ether

Protein hemocyte sedimentAcidic enzyme solution(such as gastric protease, etc.)

Pigment substancesDilute bleach solutionHydrogen peroxide