Analytical method transfer

Importance of the topic

Near-infrared spectroscopy (NIRS) is a versatile, rapid and non-destructive analytical tool widely used in research and industry. Transferring established NIR methods across instruments enables laboratories and production sites to save time and costs, harmonize quality control procedures, and benefit from improvements in instrument technology without redeveloping calibrations from scratch.

Study objectives and overview

This white paper outlines workflows and best practices for transferring NIR analytical methods between various instrument configurations. It categorizes transfer scenarios into:

• Identical instruments
• Similar instrument models
• Cross-vendor technology platforms
• Laboratory to process analyzers
• Regulated pharmaceutical transfers

Each scenario introduces specific challenges, required steps and validation criteria.

Methodology and Instrumentation used

All method transfers follow five core phases:

1. Preparation: define scope, acceptance criteria and roles
2. Method transfer: apply data standardization or conversion
3. Validation: verify prediction errors against acceptance limits
4. Method update: adjust slope and bias or add representative spectra
5. Routine application: deploy the method in daily operations

Instrumentation used

Key instrument platforms discussed include:

• Metrohm NIRS XDS Rapid Content Analyzer (dispersive Vis-NIR)
• Metrohm NIRS DS2500 (dispersive Vis-NIR)
• Fourier transform NIR analyzers (FT-NIR)
• Vision Air Server software for global QC networking

Key results and discussion

• Transfer between identical dispersive instruments achieved prediction errors equivalent to the original analyzer, enabling immediate use without recalibration.
• Upgrading to a newer model typically requires spectral data conversion using vendor software and may involve simple slope/bias updates; full method redevelopment is recommended to exploit improved specifications.
• Cross-vendor transfers introduce additional error from standardization and technology differences; transferred methods should be treated as interim solutions pending full redevelopment.
• Laboratory-to-process transfers face challenges from varying sample conditions (temperature, flow, turbidity) and may increase prediction error; careful validation and slope/bias adjustments are essential.
• Pharmaceutical transfers of analytical procedures follow strict protocols (TAP), with documented responsibilities, preapproved plans, and compliance with USP and Ph.Eur. chapters on method validation and verification.

Benefits and practical applications

• Cost and time savings by avoiding full recalibration.
• Global harmonization of QC across multiple sites.
• Enhanced analytical performance through updated hardware.
• Improved compliance in regulated industries via standardized transfer protocols.

Future trends and potential applications

• Expanded use of networked instrument software for real-time global monitoring and remote troubleshooting.
• Integration of NIR method transfers into industry 4.0 and PAT frameworks for continuous process optimization.
• Adoption of advanced chemometric algorithms and machine-learning models to minimize transfer errors.
• Increased emphasis on digital twin concepts linking laboratory and process analytics.

Conclusion

Effective NIR method transfer maximizes return on calibration investments, supports harmonized quality control and accelerates deployment of improved analytical technologies. By following structured workflows—tailored to instrument compatibility and regulatory requirements—laboratories can seamlessly adopt new hardware or expand analysis into process environments.

Reference

• Metrohm application note AN-NIR-011: Calibration model transfer of caffeine on the NIRS XDS.
• Metrohm application note AN-NIR-028: Data and method transfer from System II to NIRS XDS/DS2500.
• Metrohm application note AN-NIR-043: Analytical data transfer between FT-NIR and dispersive NIR.
• Metrohm white paper WP-020: Near-infrared spectroscopy technology comparison.
• Burns & Ciurczak, Handbook of Near-Infrared Analysis, 3rd ed., CRC Press, 2007.
• USP <1219>, <1224>, <1225>, <1226>; Ph.Eur. chapter on near-infrared spectroscopy; ICH Q2(R1).