Cleaning Method for pH Meter after Measuring Dairy Products
① When measuring ordinary dairy samples containing protein: Soak the electrode in pepsin hydrochloric acid solution (0.1 mol/L HCl) for 15 minutes, or soak it in 10% sodium hypochlorite solution for 5 minutes. Afterwards, rinse with pure water, then soak the electrode in 3.3 mol/L KCL electrode soaking solution for 12 hours to balance the electrode potential. This can restore the original activity of the electrode. If the effect is unsatisfactory, consider replacing the electrode.
② When measuring high-protein and high-fat dairy products: Soak the pH meter electrode in dishwashing detergent for 1 hour. Take out and rinse the electrode thoroughly, then immerse it in pepsin solution for 4 hours. Preparation of pepsin solution: mix 5% pepsin solution and 0.5 mol/L hydrochloric acid solution at a volume ratio of 1:1. Finally, take out the electrode, rinse thoroughly with distilled water, and soak it in 3 mol/L (3.3 mol/L precisely) KCL solution for standby. The electrode interior shall also be filled with 3 mol/L KCL solution to prevent drying out.
pH meters are widely applied in the dairy industry and play an important role in the testing of semi-finished and finished products. The pH value reflects the quality of the tested material. Failure to obtain accurate pH readings timely for production reference will cause immeasurable impacts on production.
Dairy products are high in protein and fat, which tend to clog the capillary tubes of the electrode glass bulb. Normally used electrodes usually show slow response and unstable readings after about three months. Proper cleaning helps reduce operating costs and rationally allocate resources.
