The method used by the pH meter and the maintenance electrode of the pH meter
First, the installation of the acidity meter
①The voltage and frequency of the power supply must comply with the data specified on the nameplate of the instrument, and must be well grounded, otherwise the pointer may be unstable during measurement.
② The instrument is equipped with glass electrodes and calomel electrodes. Clip the Bakelite cap of the glass electrode to the small clip of the electrode holder. Clip the metal cap of the calomel electrode onto the large clip of the electrode holder. The height of the two electrodes can be adjusted using the standoff screws on the electrode holder.
③The glass electrode must be soaked in distilled water for more than 24 hours before the first use. It should also be soaked in distilled water when not in use.
④ Before the first use of the calomel electrode, it should be soaked in a saturated potassium lvide solution, and not soaked in distilled water with the glass electrode. When not in use, also soak in saturated potassium lv3 solution or cover the capillary at the lower end of the calomel electrode with a rubber cap.
Secondly, correction
①Turn the "pH-mv" switch to the pH position.
②Turn on the power, the indicator light will be on at the beginning, and it will preheat for 30 minutes.
③Remove the small beaker containing distilled water, and use filter paper to gently absorb excess water droplets on the glass electrode. Pour the selected standard buffer solution of known pH into a small beaker. Dip the electrodes. Take care to keep the tip ball of the glass electrode and the capillary pores of the calomel electrode immersed in the solution. Gently shake the small beaker to make the solution evenly contacted by the electrode.
④ According to the pH of the standard buffer solution, turn the range switch to 0~7 or 7~14.
⑤Adjust the temperature control knob so that the temperature indicated by the knob is the same as the room temperature.
⑥Adjust the zero point so that the pointer points to pH7.
⑦ Gently press or turn the reading switch slightly to make the switch stuck. Adjust the positioning knob so that the pointer just points to the pH value of the standard buffer solution. Release the reading switch and repeat the operation until the value is stable.
⑧After the adjustment, do not turn the positioning knob again, otherwise it needs to be re-adjusted. Remove the small beaker of standard solution and rinse the electrode with distilled water.
Finally, measure
①Drain the excess water droplets on the electrode or rinse it twice with the solution to be tested, then immerse the electrode in the solution to be tested, and turn or shake the small beaker gently to make the solution contact the electrode evenly.
②The temperature of the solution to be tested should be the same as that of the standard buffer solution.
③ Adjust the zero position, press the reading switch, the value pointed by the pointer is the pH of the liquid to be tested. If the pointer reading exceeds the scale when measuring within the range of pH0~7, the range switch should be placed at pH7~14 and then measured.
④ After the measurement is completed, after releasing the reading switch, the pointer must point to pH 7, otherwise re-adjust.
⑤ Turn off the power, rinse the electrode, and soak it according to the above method.
