System Suitability Testing for Peptide Methods

System suitability verifies that the complete analytical system is performing acceptably at the time of use.

Common criteria

Depending on the method, criteria may include:

• retention-time repeatability
• peak-area repeatability
• resolution
• tailing factor
• theoretical plates
• signal-to-noise
• sensitivity
• carryover
• mass accuracy
• calibration response

Suitable test solutions

A system-suitability solution should challenge the method’s critical performance. It may contain the principal peptide, a known impurity, a resolution mixture, or a sensitivity marker.

Sequence placement

Suitability is often evaluated before samples, but long sequences may require bracketing or periodic checks to detect drift.

Failure handling

If suitability fails, sample results should not be accepted until the cause is investigated and acceptable performance is restored.

Frequently asked questions

Can the reference standard serve as system suitability?

Sometimes, if it challenges the required attributes.

Is one replicate enough?

Repeatability criteria often require multiple injections.

Can failed suitability be ignored if sample results look normal?

No. The system was not demonstrated to be fit for use.

Does passing suitability prove the method is validated?

No. It confirms run-specific performance.

Key takeaways

System suitability is the gatekeeper for an analytical run. Criteria should reflect critical method performance and be evaluated before results are reported.

References

1. ICH Q2(R2). Validation of Analytical Procedures.
2. ICH Q14. Analytical Procedure Development.
3. FDA. Analytical Procedures and Methods Validation for Drugs and Biologics.

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TSMS Labs educational disclaimer: For laboratory research and educational purposes only. Not for human consumption. This content is not medical, clinical, or regulatory advice.