How to Check Whether a pH Meter Is Accurate
How to check if the pH meter is accurate?
The reliable and simplest method is to use a pH standard buffer solution for calibration. Take three pH standard buffer solutions: pH 6.86, pH 4.00, and pH 9.18 (preferably freshly prepared and at the same temperature), perform positioning calibration with pH 6.86, slope calibration with pH 4.00, and then test pH 9.18 to see if the pH meter is accurate and qualified. If the accuracy is not up to standard, it can be further determined whether there is a problem with the pH meter or the pH electrode.
When the pH electrode is contaminated and causes a decrease in performance or cannot be used, please clean it according to the following methods before calibration, which may restore the pH electrode. Otherwise, please purchase a new pH electrode:
Soak in 0.1mol/L HCl or HNO for half an hour, then soak in storage solution for another hour.
2. Cleaning of electrode deposits:
2-1. Protein: Soak in a 1% gastric protease hydrochloric acid solution (HCl concentration of 0.1mol/L) for 15 minutes, or soak in a 10% sodium hypochlorite solution for 5 minutes.
2-2. Inorganic substances: Soak in a 0.1mol/L EDTA solution for 15 minutes.
2-3. Fats and oils: Clean with mild detergent or methanol solution.
3. After cleaning, let it dry and check the amount of liquid filling (if it is too small, please fill it). Then, place the pH electrode in the storage solution for at least 1 hour.
If there is no storage solution, add 1g KCl to 200mL (pH=7 buffer solution) solution and shake well before temporary use.
