How to use a pH meter? How to use a pH meter (steps)
1. Open the back cover and insert a battery.
2. Attention when installing composite glass electrodes:
(1) The lower end of the composite electrode is a fragile glass bubble, so be careful when using and storing it to prevent collision with other items.
(2) There is a saturated KCl solution as a conductive medium inside the composite electrode. If the drying result is inaccurate, it is necessary to observe the presence of liquid at any time. If a small amount is found remaining, it should be poured into the laboratory.
(3) The interface of the composite electrode instrument must not be contaminated, including water droplets.
(4) The composite electrode connection cannot be forcibly pulled to prevent the line joint from breaking.
3. After turning on the power switch, switch to the pH measurement mode.
4. Measure the temperature of PH6.86 standard solution with a thermometer, and then adjust the temperature compensation knob of the pH meter to the measured temperature value.
5. Rinse the composite electrode clean with deionized water and dry it with filter paper.
6. Pour 2-5ml of PH6.86 standard solution into a plastic beaker that has been washed and dried with water. After washing the beaker and composite electrode, pour them out. Then add 20ml of PH6.86 standard solution to the plastic beaker, insert the composite electrode into the solution, and use the instrument positioning knob to adjust the reading to 6.86 until stable. The following two points should be noted:
(1) The positioning must be adjusted using PH6.86 standard.
(2) After adjustment, never move the positioning knob again.
7. Wash the composite electrode with deionized water, dry it with filter paper, measure the temperature of the pH 4.00 solution with a thermometer, and adjust the temperature compensation knob of the instrument to the measured temperature value.
8. Pour 2-5ml of PH4.00 standard solution into another plastic beaker, wash the beaker and composite electrode, and discard. Then add 20ml of PH4.00 standard solution and insert the composite electrode into the solution. After the reading stabilizes, use the slope knob to adjust to PH4.00. It should be noted that after adjusting the slope knob, it must not be moved again.
9. Measure the temperature of the liquid to be tested with a thermometer and adjust the temperature compensation of the instrument to the measured temperature.
10. Insert the composite electrode into the test solution and read the pH value, which is the pH value of the test solution. The following two points should be noted:
(1) When measuring, the temperature should not be too high. If the temperature exceeds 40 ℃ and the measurement result is inaccurate, it needs to be taken out of a beaker and cooled slightly.
(2) Composite electrodes should avoid contact with organic matter. Once in contact or contaminated, they should be cleaned with anhydrous ethanol.
11. Attention: The instrument must be calibrated before use, including the above 4-8 operations. If the instrument is not turned off, it can be continuously measured, but once it is turned off, it needs to be calibrated. But it must be calibrated once every 12 hours even if it is not turned off.
