JAGAN Quality assurance pharmacy seminor

Quality assurance

1. CALIBRATION OF PH METER By Jagan

2. INTRODUCTION * A pH meter is an electronic instrument used for measuring the pH (acidity o r measurin g or alkalinity) of a liquid (though special probes are sometimes used to measure the pH of semi-solid substances). * A typical pH meter consists of special measuring probes (a glass electrode and a reference electrode) connected to an electronic meter that measures and displays the pH reading.

3. WHAT IS CALIBRATION? * The process of comparing the response of some instrument or system to a standard instrument or system over some measurement range. * To maintain the accuracy and precision of test equipment at all times. * It is used to detect, correlate, report or eliminate by adjustment of any variation in the accuracy of the equipment being calibrated.

4. NEED OF CALIBRATION * When a specific time period is elapsed. * When a specific operating hours has elapsed. * With a new instrument . * When observations appear questionable .

5. PROCEDURE FOR CALIBRATING THE PH METER T he following four steps in the calibration of pH meters . Step 1: Clean the Electrodes * If working with laboratory equipment and chemicals, it is important to wear proper safety equipment, such as gloves and safety glasses. After turning on the power to the pH meter, take the pH meter electrode from its storage solution and rinse with distilled water. Wipe it clean with a lint-free tissue. 1

6. 2 Step 2: Calibrate With the pH 7 Buffer * Submerge the rinsed electrode into the pH 7 buffer solution. Press the calibrate button and wait for the pH icon to stop flashing. If the pH reads 7, accept; if it does not, edit the entry using the keypad on the instrument. Rinse the electrode again with distilled water and wipe clean with a lint-free tissue. _________________________________________________________________________________

7. 3 _______________________________________________________________________________________ Step 3: Calibrate With the pH 10 Buffer * Now submerge the rinsed electrode into the pH 10 buffer. Press the calibrate button once the pH icon stops flashing. If the pH reads 10, accept; if it does not, edit the entry using the keypad on the instrument. Rinse the electrode with distilled water and wipe with a lint-free tissue.

8. 4 _____________________________________________________________________________________ Step 4: Measure the pH of Solutions * The pH meter is now ready to measure the pH of other substances. Be sure to submerge the electrode and rinse with distilled water in between multiple samples.