Standard Operating Procedure (SOP)

Here’s a detailed Standard Operating Procedure (SOP) for Calibration of Headspace Gas Chromatograph (HS-GC) tailored for pharmaceutical or analytical lab settings. This SOP ensures accurate, reliable, and reproducible performance of the HS-GC system.

1. Objective

To establish a procedure for the calibration of the Headspace Gas Chromatograph to ensure accurate and consistent analysis of volatile organic compounds in pharmaceutical samples.

2. Scope

This procedure applies to all Headspace Gas Chromatography systems used in [Company Name]’s laboratory for routine and method-specific analysis.

3. Responsibilities

• Analyst: Perform calibration and document the results.

• QA Officer/Supervisor: Verify calibration and ensure compliance with SOP.

• Instrument Engineer (if applicable): Assist in troubleshooting and maintenance.

4. Definitions

• HS-GC: Headspace Gas Chromatograph, an analytical technique used for the analysis of volatile components in samples.

• Calibration: Verification that the instrument produces results within acceptable limits when tested with standards of known concentrations.

• FID: Flame Ionization Detector

• ECD: Electron Capture Detector

5. Materials and Equipment

• Calibrated Headspace GC system (e.g., Agilent, PerkinElmer, Shimadzu)

• Standard solutions (certified reference materials or prepared in-house as per method)

• Headspace vials, septa, and crimp caps

• Analytical balance (calibrated)

• Volumetric flasks, micropipettes

• Calibration logbook or software

6. Procedure

6.1 General Precautions

• Ensure the instrument is properly maintained and leak-checked.

• Use certified reference standards.

• Follow proper safety and handling procedures for volatile solvents.

• Ensure headspace vials are clean and sealed properly.

6.2 Instrument Preparation

1. Switch on the GC and Headspace sampler.

2. Allow the system to stabilize (as per manufacturer’s instructions).

3. Check gas flow (carrier gas, makeup gas, etc.).

4. Set the appropriate method parameters (oven temp, injector temp, detector temp, vial equilibration time, pressure, etc.).

6.3 Calibration Standard Preparation

1. Prepare at least five levels of calibration standards (e.g., 50%, 75%, 100%, 125%, and 150% of target concentration).

2. Use appropriate diluent and volumetric glassware.

3. Transfer aliquots into headspace vials and seal with crimp caps.

6.4 System Suitability

1. Run a blank injection to ensure no carryover.

2. Inject system suitability standard (e.g., known concentration of target analyte).

3. Check parameters like:

   • Retention time repeatability (RSD ≤ 1.0%)

   • Area repeatability (RSD ≤ 2.0%)

   • Resolution between critical peaks (as per method)

6.5 Calibration

1. Inject the calibration standards in ascending order of concentration.

2. Record retention time and peak area for each injection.

3. Plot a calibration curve (concentration vs. peak area or height).

4. Calculate linearity and correlation coefficient (r ≥ 0.999).

5. Ensure all calibration points fall within acceptable limits (±15% of nominal).

7. Acceptance Criteria

• Correlation coefficient (r) must be ≥ 0.999.

• System suitability parameters within specified limits.

• Residuals of calibration curve should not exceed ±15%.

• Blank should show no peak at analyte RT.

8. Frequency of Calibration

• Routine calibration: As per method requirements or monthly.

• After instrument maintenance or repairs

• Before starting any critical or stability batch analysis

• If any deviation or malfunction is observed

9. Documentation

• Calibration report with chromatograms

• Calibration curve and calculations

• System suitability report

• Instrument logbook entry

• QA verification record

10. Abbreviations

• HS-GC: Headspace Gas Chromatograph

• FID: Flame Ionization Detector

• ECD: Electron Capture Detector

• SOP: Standard Operating Procedure

• RSD: Relative Standard Deviation

• RT: Retention Time

11. References

• Instrument manufacturer’s manual

• ICH Q2(R1): Validation of Analytical Procedures

• USP <467> (Residual Solvents)

• Company Quality Manual.

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