This Standard Operating Procedure (SOP) applies to staff and students using the Bench-Top pH Meter in the laboratories.
To describe the procedure for installation, operation, calibration, maintenance and troubleshooting of the Bench-Top pH Meter.
(a). ↑ oC and ↓ oC Keys: To set the temperature for Manual Temperature
(b). Automatic Temperature Compensation …show more content…
- Press the On/Off Key to switch on the meter.
- Rinse the pH electrode with some pH 7.01 buffer solution.
- Immerse the pH electrode into the pH 7.01 buffer solution and stir gently.
- Ensure that the pH electrode is kept submerged approximately 4cm into the solution.
- Ensure that the temperature probe is located as close to the pH electrode as possible.
- Press the CAL Key.
- Wait until the pH symbol, next to the pH buffer value, stops flashing to indicate that reading is stable.
- Press the CON Key to confirm the calibration.
- If [E 4] is flashing, ensure that the correct buffer solution is being used.
- Wait until [E 5] is displayed to indicate that the electrode is still in the pH 7.01 buffer, but expecting a pH 4.01 or 10.01 buffer.
- Rinse the pH electrode with distilled water followed by the second buffer solution to be used.
- Immerse the pH electrode into the second buffer solution (pH 4.01 or pH 10.01) and stir gently.
- Wait until the pH symbol, next to the pH buffer value, stops flashing to indicate that the reading is …show more content…
- Inspect the pH electrode for any cracks in its stem or bulb.
- Rinse off any salt desposits with water.
- Soak the pH electrode in General Cleaning Solution for approximately ½ hour to perform general cleaning.
- Soak the pH electrode in Protein Cleaning Solution for 15 minutes if protein deposits are present on the membrane and/or junction of the electrode.
- Soak the pH electrode in Inorganic Cleaning Solution for 15 minutes if inorganic deposits are present on the membrane and/or junction of the electrode.
- Rinse the pH electrode with Oil and Fat Cleaning Solution if oil films or deposits are present on the membrane and/or junction of the electrode.
- Rinse the pH electrode thoroughly with distilled water after performing any of these cleaning procedures.
- Refill the reference chamber with fresh electrolyte and soak it in Storage Solution for at least 1 hour before taking any measurements.
- Always keep the pH electrode wet and rinse it thoroughly with the sample to be measured before use.
- In order to measure the pH accurately, the temperature factor must always be taken into