In all walks of life, especially in the fields of scientific research, environmental protection, industry and agriculture, PH meters (pH meters) are increasingly widely used. Proper use and maintenance of PH meters is essential to ensure the accuracy of experimental data.

Basic principle

PH meter is an instrument for measuring the pH of solution, which is composed of reference electrode, glass electrode and galvanometer. It determines PH by measuring the concentration of hydrogen ions in a solution and is often used for accurate pH measurements.

Enable the PH meter correctly

The PH meter assembly should be properly assembled before use, to ensure that the voltage and frequency of the power supply and the environment meet the requirements of the instrument, and to ensure good grounding to maintain measurement stability. The new glass electrode needs to be soaked in distilled water for more than 24 hours, and the calomel electrode needs to be soaked in a saturated potassium chloride solution to ensure its sensitivity and accuracy.

Preparation of standard buffers

A PH standard buffer is prepared using pure reagents and distilled water. For example, buffers with PH=4.00, 6.88, and 9.18 need to be proportionally prepared with specific chemicals, respectively. Standard buffers should be stored in a dry place to avoid deliquesation and carbonation, which can affect PH.

Proper use and maintenance of PH meter

Calibration of PH meter

Two standard buffers are used for calibration, usually PH=7 and PH=4 or PH=9 buffers. Select the appropriate second buffer according to the acidity and alkalinity of the solution to be tested. Frequently used PH meters are recommended to be calibrated every 48 hours, especially after measuring extremely acidic or alkaline solutions, or after the electrodes have been exposed to air for more than 0.5 hours.

Use and maintenance of PH electrodes

When in use, the rubber sleeve of the electrode feeding port and the rubber sleeve at the lower end should be removed to maintain the circulation of potassium chloride solution in the electrode. When not in use, the PH composite electrode should be soaked in 3mol potassium chloride solution. Avoid using detergents or other absorbent reagents to clean the electrodes. Regularly check whether the electrode bulb is intact to ensure that there are no bubbles and cracks.

The correct use and maintenance of the PH meter can not only extend its service life, but also ensure the accuracy and reliability of the experimental data. Therefore, mastering the operation details and maintenance skills of PH meters is of Paramount importance for professionals in related fields.