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Good Chromatography Practices (GCP)

Shahzaib Aftab February 13, 2026

Comprehensive SOP for Good Chromatography Practices in pharmaceutical quality control laboratories. Covers HPLC & GC system suitability, method adjustments, data integrity, column care, and compliance requirements.

Good Chromatography Practices (GCP)

SOP for Good Chromatography Practices (GCP)

In pharmaceutical quality control laboratories, maintaining Good Chromatography Practices (GCP) is essential to ensure accuracy, reliability, and regulatory compliance during HPLC and GC analysis. This SOP outlines standardized procedures for system suitability, method adjustments, data handling, and equipment care.

1.0 Objective

To establish a standardized procedure for implementing Good Chromatography Practices during HPLC and GC analysis.

2.0 Scope

This SOP applies to all HPLC and GC analyses conducted in the Quality Control (QC) department for pharmaceutical products.

3.0 Responsibility

QC Officer / QC Chemist

4.0 Accountability

Head of Department – QC

5.0 Procedure

5.1 System Suitability

System suitability ensures that chromatographic systems are performing correctly before sample analysis.

5.1.1 Response Measurement

  • Peak area or peak height shall be considered as detector response.
  • Only average area and %RSD from the summary report shall be recorded.

5.1.2 Acceptance Criteria

  • Only system suitability parameters specified in the method of analysis shall be evaluated.

5.1.3 Replicate Injections

  • If %RSD limit ≤ 2.0% → Perform 5 consecutive injections
  • If %RSD limit > 2.0% → Perform 6 consecutive injections
  • %RSD shall be calculated using sequential injections only.

5.1.4 Bracketing Standard

  • Inject as specified in the method.
  • %RSD limit = 1.5 × original system suitability limit.

5.2 When System Suitability is Not Specified

If the method does not define criteria:

  • Assay / Dissolution / Content Uniformity: 5 replicate injections, %RSD ≤ 2.0%
  • Related Substances (Non-BP): Single injection
  • Related Substances (BP methods): Minimum 3 injections, %RSD ≤ 5.0%
  • Residual Solvents: 6 replicate injections, %RSD ≤ 15%

5.3 Interruption During HPLC Run

In case of interruption (up to 6 hours) due to:

  • Power failure
  • Computer interruption
  • Sample delay

Requirements:

  • Inject bracketing standard before continuing.
  • Applicable only if the system remains equilibrated.

5.4 Retention Time Criteria

  • Retention time deviation should not exceed ±15% of specified value.
  • For related substances, compare sample retention time with specified standard.

5.5 Related Substances Run Time

Chromatogram must run at least 1.5 times the retention time of the principal peak, unless otherwise specified.

5.6 Allowed Adjustments – Liquid Chromatography (HPLC)

Under Good Chromatography Practices, adjustments may be made only with prior QC Head approval.

Permitted Adjustments:

  • Mobile Phase Composition:
          Minor solvent ±10% relative or ±2% absolute (whichever larger)

  • pH Adjustment:
          ±0.05 pH (general)
          ±1.0 pH (neutral substances)

  • Buffer Salt Concentration:
           ±10%

  • Detector Wavelength:
          ❌ No adjustment permitted

  • Column Length: ±70%
  • Column ID: ±25%
  • Particle Size: Max 50% reduction (no increase)
  • Flow Rate: ±50%
  • Temperature: ±10% (max 60°C)
  • Injection Volume: May decrease if repeatability maintained

Gradient Elution Note

Equipment configuration and dwell volume may affect resolution and retention times.

5.7 Allowed Adjustments – Gas Chromatography (GC)

  • Stationary Phase: No change permitted
  • Column Length: ±70%
  • Column ID: ±50%
  • Particle Size: Max 50% reduction
  • Film Thickness: -50% to +100%
  • Flow Rate: ±50%
  • Temperature: ±10%
  • Injection Volume: May decrease if acceptable repeatability achieved

5.8 Data Generation & Integrity

Maintaining data integrity is a core element of Good Chromatography Practices.

5.8.1 Method Files

  • Verify compliance before saving.
  • Perform trial runs if integration parameters are unknown.
  • Use consistent integration parameters throughout.
  • Record reason for any modification.
  • Print and sign final method parameters.

5.8.2 Data Files

  • Use unique file names.
  • Reprocess all related files together if reprocessing is required.
  • Ensure consistent processing method during sequence.
  • Sign all printouts.
  • Data description must be clearly present.

5.8.3 Sequence Files

  • Avoid duplicate file names.
  • Enter product details properly.
  • Print and sign sequence after testing.
  • Amend only before execution.

5.9 Logbook Entries

  • Attach all rejected or failed injection data.
  • Document justification for exclusion.
  • Analyst must sign printed data.
  • QC must review and approve.
  • Excel-generated results (e.g., dissolution, content uniformity) may be pasted as final results after review.

5.10 Column Care

Proper column handling extends column life and ensures reproducibility.

  • Store columns in original casing.
  • Avoid physical shock.
  • Flush with miscible solvents.
  • Replace end fittings after use.
  • Confirm correct flow direction.
  • Check for leaks before closing compartment.

5.11 Precautions

  • Prevent air bubbles in solvent path.
  • Filter or centrifuge samples.
  • Use 0.45µ (or finer) filtered and sonicated mobile phase.
  • Verify vial placement in auto-sampler.
  • Check mobile phase clarity.
  • Ensure proper GC gas flow.
  • Inject blanks to prevent carryover when necessary.

6.0 Abbreviations

  • QA – Quality Assurance
  • QC – Quality Control
  • RSD – Relative Standard Deviation
  • SOP – Standard Operating Procedure
  • HOD – Head of Department
  • HPLC – High Performance Liquid Chromatography
  • GC – Gas Chromatography

Why Good Chromatography Practices Matter

Implementing Good Chromatography Practices ensures:

  • Regulatory compliance
  • Reproducible analytical results
  • Improved system performance
  • Extended column life
  • Strong data integrity
  • Reduced out-of-specification (OOS) results

In pharmaceutical quality control, consistency and compliance are non-negotiable—and GCP forms the backbone of reliable chromatographic analysis.

Frequently Asked Questions (FAQs)

1. What are Good Chromatography Practices (GCP)?

Good Chromatography Practices are standardized procedures followed during HPLC and GC analysis to ensure accuracy, reproducibility, compliance, and data integrity in pharmaceutical laboratories.

2. How many injections are required for system suitability?

Typically, 5 injections are required if %RSD ≤ 2.0%, and 6 injections if %RSD > 2.0%, unless otherwise specified in the method.

3. Can chromatographic conditions be adjusted?

Yes, limited adjustments (mobile phase, pH, flow rate, column dimensions) are allowed under defined limits and with prior QC approval.

4. What should be done if an HPLC run is interrupted?

If interruption occurs within 6 hours and the system remains equilibrated, inject a bracketing standard before continuing analysis.

5. Why is column care important in chromatography?

Proper column care ensures consistent performance, prevents contamination, extends column life, and supports reliable analytical results.

Shahzaib Aftab

Posted by Shahzaib Aftab

Shahzaib Aftab is a leading pharmaceutical blogger and author from Pakistan, and the founder of webofpharma.com, a trusted pharmaceutical knowledge platform serving professionals since 2018. He is committed to simplifying complex pharmaceutical standards, regulatory requirements, and pharmacopeial knowledge for students and industry professionals worldwide.