Laboratory Analyzer Calibration – Master Technical Guide
Calibration ensures measurement accuracy, regulatory compliance, and traceability. Poor calibration practice is the root cause of most laboratory result deviations.
Types of Calibration
External Standard
- Known concentration standard
- Used for GC, HPLC, UV
- Simple implementation
Internal Standard
- Compensates injection variability
- Improves repeatability
- Used in high precision analysis
Calibration Process Flow
- Select certified reference material (CRM)
- Prepare calibration standards
- Run blank test
- Generate calibration curve
- Verify linearity (R² ≥ acceptable limit)
- Validate with check standard
Key Calibration Parameters
- Response factor stability
- Retention time consistency
- Detector sensitivity
- Baseline stability
- Repeatability (RSD%)
- Measurement uncertainty
Common Calibration Failures
- Drift in response factor
- Non-linear calibration curve
- Contaminated standard
- Column degradation (GC/HPLC)
- Improper detector configuration
Traceability & Compliance
- ISO 17025 compliance
- Maintain calibration records
- Use certified CRMs
- Document uncertainty estimation
- Schedule periodic validation
Calibration is not adjustment — it is verification against a known standard.