Standard Operating Procedure for Calibration of pH Meters

1) Purpose

The purpose of this SOP is to define the procedure for calibrating pH meters to ensure accurate and reliable pH measurements in pharmaceutical manufacturing.

2) Scope

This SOP applies to all pH meters used within the facility premises.

3) Responsibilities

The Quality Control Department and designated laboratory personnel are responsible for implementing and adhering to this SOP.

4) Procedure

1. Equipment Preparation
   1. Ensure the pH meter is clean and in good working condition.
   2. Verify availability of calibrated pH buffers (typically pH 4.01, 7.00, and 10.01).
2. Calibration Process
   1. Place the pH meter electrode in the pH 7.00 buffer solution and allow stabilization.
   2. Adjust the pH meter reading to match the pH 7.00 buffer value using calibration controls.
   3. Rinse the electrode with distilled water and repeat the process with pH 4.01 and 10.01 buffers, adjusting readings accordingly.
3. Verification
   1. Verify calibration accuracy by checking readings against additional buffer solutions or known pH standards.
   2. Document calibration results, including calibration dates, readings, and adjustments made.
4. Post-Calibration Checks
   1. Perform additional checks if the pH meter is used for critical measurements, ensuring ongoing accuracy and reliability.
   2. Label or mark calibrated pH meters to indicate calibration status and next due date.

5) Abbreviations, if any

SOP: Standard Operating Procedure

6) Documents, if any

pH Meter Calibration Log, Calibration Certificates for pH Buffers, SOP for pH Meter Maintenance

7) Reference, if any

Manufacturer’s instructions for pH meter calibration, pharmacopeial standards (e.g., USP), and internal quality control procedures.

8) SOP Version

Version 1.0