How to use the pH meter correctly

First of all, the pH meter's installation 1 The voltage and frequency of the power supply must be in accordance with the data indicated on the instrument's nameplate and must be well grounded, otherwise the pointer may be unstable during measurement.

2 The instrument is equipped with a glass electrode and a calomel electrode. The bakelite cap of the glass electrode was clamped on the small clip of the electrode holder. The calomel electrode's metal cap was clamped on the large clamp of the electrode holder. The height of the two electrodes can be adjusted using the head screws on the electrode holder.

3 Glass electrodes must be soaked in distilled water for more than 24 hours before initial use. Should not be soaked in distilled water.

4 The calomel electrode should be soaked in saturated potassium chloride solution before its initial use. Do not soak it in distilled water with the glass electrode. When not in use, soak in saturated potassium chloride solution or cap the lower capillary of the calomel electrode with a rubber cap.

Next, calibration 1 will switch the "pH-mv" switch to the pH position.

2 Turn on the power indicator light at the beginning and warm it up for 30 minutes.

3 Remove the small beaker of distilled water, and use the filter paper to gently remove the excess water on the glass electrode. In a small beaker, select a standard buffer solution of known pH. Immerse the electrode. Note that the capillary of the glass electrode tip and the calomel electrode are immersed in the solution. Gently shake the small beaker so that the electrode is in contact with the solution.

4 Screw the range switch to 0-7 or 7-14 depending on the pH of the standard buffer.

5 Adjust the temperature control knob so that the temperature indicated by the knob is the same as the room temperature.

6 Adjust the zero point so that the pointer is at pH 7.

7 Press lightly or slightly turn the reading switch to make the switch jam. Adjust the positioning knob so that the pointer is exactly at the pH value of the standard buffer. Release the reading switch and repeat until the value is stable.

8 After alignment, do not turn the positioning knob again, otherwise it will need to be re-aligned. Remove the standard small beaker and rinse the electrode with distilled water.

Finally, measurement 1 The excess water on the electrode is sucked dry or washed twice with the solution to be tested, then the electrode is immersed in the solution to be measured, and the beaker is gently rotated or shaken to make the solution evenly contact the electrode.

2 The temperature of the test solution should be the same as that of the standard buffer solution.

3 Zero calibration, press the reading switch, the value indicated by the pointer is the pH of the test solution. If the pointer reading exceeds the scale when measuring in the range of pH 0~7, the range switch should be set to pH 7~14 and measured again.

4 After the measurement is completed, after releasing the reading switch, the pointer must be at pH 7, otherwise readjust.

5 Turn off the power, rinse the electrodes, and soak as described above.