Rinse the pH electrode first with deionized water and then in the pH 10.01 buffer rinse beaker. 2. Handling. Never wipe an electrode wiping can cause erroneous readings due to static charges. If you store the electrode dry, this hydration layer will be destroyed. Because of the difficulty (impossibility) in the accurate measurement of pH in ultrapure water, ASTM has at least removed the requirement from the specification for Type I and Type II deionized water. Even though the layer can be recovered by conditioning the sensor in deionized water, the sensor will become slower. Electrodes should be rinsed between samples with distilled or deionized water. After conditioning the sensor for 20 minutes, rinse the electrode with distilled or deionized water. Never store the pH electrode dry! The electrode should never be rinsed in the same buffer beaker that will be used for calibration … The concentration of the ions H+ and OH- in perfect water is 0.0000001 molar at 25° C. The pH of this water is exactly 7. A strength adjuster adds extra ions in the water without changing the pH. For further calibration purposes and precise pH measurements of distilled deionized waters – Ionic Strength Adjusters are used. Hanna's technical calibration buffer produced in accordance with ISO 3696/BS3978 standards using high purity salts, deionized water, certified weight-checked balances, and Class A glassware in a temperature controlled environment monitored with certified thermometers. The glass membrane builds up a hydration layer, which is necessary for proper pH measurement. The electrode is now ready for calibration and to measure pH. Make sure to rinse the electrode with deionized water over a waste beaker to prevent contamination of the buffers.