CALIBRATION OF pH METER

this document includes calibration, procedure of calibration, calibration, validation,
calibration of ph meter

1. CALIBRATION OF pH METER VIKAS PRAJAPATI REG NO. 72012769 B.PHARMACY 6 TH SEM

2. INTRODUCTION  A pH meter is an electronic instrument used for measuring the pH (acidity 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. PRINCIPLE  pH is defined as the negative logarithm of hydrogen ion concentration.  pH= -log [ H+ ]  p = power  H = hydrogen [H+ ] = hydrogen ion concentration  The pH of a solution can be measured by the pH meter. The glass electrode is an half cell and the calomel electrode is another half cell.

4. 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. To ensure highest level of confidence in all measurement that affect materials disposition decision, with unbroken chain of traceability to national standard. To determine whether the equipment is still fit for its intended purpose. It is based on the comparison of a primary standard or instrument of known accuracy with another equipment (to be calibrated) It is used to detect, correlate, report or eliminate by adjustment of any variation in the accuracy of the equipment being calibrated.

5. 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.

6. DIFFERENCES IN CALIBRATION AND VALIDATION Calibration Calibration assures accuracy of measurements. It is a process that ensures that accuracy is maintained in measurements produced by your equipment. Validation Validation provide proof of consistency across all the processes, batches of product or methods being used. It is a documented process that provides assurance that a product, service or system consistently provides result within the acceptable criteria.

7. CONTINUE DIFFERENCES… Calibration performance of any equipment is compared against a reference standard. It should be performed as per calibration SOP. You must periodically calibrate your instruments. Identify if there is a ‘drift’ in measurements and eliminate it through calibration. There are no reference standard used in validation. It should be performed as per validation protocol. There are no such requirements in validation. It should be performed when you make any change in the existing system or when the revalidation period has been reached.

8. PROCEDURE FOR CALIBRATING THE PH METER Calibration of pH Meters Use the 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.

9. STEP 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.

10. STEP 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.

11. STEP 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.

12. THANK YOU!