Standard Operating Procedure for Calibration of pH Meters

1) Purpose

The purpose of this SOP is to establish the procedures for calibrating pH meters to ensure accuracy and reliability in pH measurements as per regulatory requirements in the pharmaceutical industry.

2) Scope

This SOP applies to all pH meters used in the pharmaceutical manufacturing process.

3) Responsibilities

The Quality Assurance Department is responsible for implementing and adhering to this SOP. All personnel involved in the calibration process must be trained and qualified.

4) Procedure

1. Calibration Schedule Establishment
   1. Develop a calibration schedule based on pH meter criticality, manufacturer recommendations, and regulatory requirements.
   2. Assign unique identification numbers or labels to each pH meter for traceability.
   3. Document calibration frequency and tolerance limits for each pH meter.
2. Calibration Process
   1. Retrieve the pH meter to be calibrated from its designated location.
   2. Verify the pH meter’s identity and check its condition for any physical damage.
   3. Prepare calibration buffers of known pH values and temperature.
   4. Calibrate the pH meter using certified calibration buffers and procedures.
   5. Record calibration results including before and after values, adjustments made, and calibration date.
   6. Apply calibration labels indicating next due date and calibration status.
3. Out-of-Tolerance Conditions
   1. If a pH meter is found out-of-tolerance, quarantine it immediately and perform investigation to determine impact.
   2. Take corrective action, recalibrate if possible, or