Analytical method transfer

Importance of the Topic

Near-infrared spectroscopy (NIRS) is a cornerstone technique for rapid qualitative and quantitative analysis across research and industrial settings. Transferring existing NIR methods between instruments or sites preserves investment in calibration development, ensures consistent quality control worldwide, and enables adoption of improved hardware to enhance analytical performance.

Objectives and Overview of the Study

This white paper defines a structured workflow for migrating NIR analytical methods from a source laboratory or instrument to a receiving one. It examines various transfer scenarios—identical models, upgraded instruments, cross-vendor conversions, laboratory-to-process applications, and pharmaceutical-regulated transfers—highlighting validation strategies, challenges, and the trade-offs between redeveloping methods versus transferring them.

Methodology and Instrumentation

The recommended workflow comprises five phases:

• Preparation: establish scope, responsibilities, and a documented transfer protocol.
• Transfer: perform data standardization or apply a transfer function to calibration sets.
• Validation: verify model performance using an independent sample set.
• Model Update: apply slope/bias adjustments or redevelop if performance targets are not met.
• Routine Application: implement the transferred method in regular operation.

Key instrumentation and software include:

• Dispersive Vis-NIR spectrometers (e.g., Metrohm NIRS XDS, DS2500).
• FT-NIR analyzers with interferometric detection.
• Vision and Vision Air Server software for spectral conversion, networked calibration management, and centralized QC monitoring.

Main Results and Discussion

The complexity and validation requirements vary by transfer type:

• Identical Instruments: direct copying of calibration models when operating conditions match yields minimal error.
• Upgraded Models: spectral conversion and minor validation (slope/bias) address changes in resolution or wavelength range.
• Lab-to-Process Transfers: account for temperature, flow, and sampling differences, typically resulting in moderate increases in prediction error.
• Cross-Vendor Conversions: require additional representative samples (15–30) to build a transfer function; combined error from original model and standardization must be managed.
• Pharmaceutical Transfers: follow a preapproved protocol under USP <1219>, <1224>–<1226> and Ph.Eur. guidelines, with documented verification, validation, and acceptance criteria per ICH Q2(R1).

The discussion emphasizes the balance between minimizing development time and meeting performance and regulatory demands.

Benefits and Practical Applications

Effective method transfer delivers:

• Significant time and cost savings by avoiding full-scale method redevelopment.
• Synchronized and centralized QC across global production sites via networking software.
• Enhanced analytical precision through adoption of advanced instruments.
• Regulatory compliance with documented validation and verification protocols.
• Proactive out-of-spec and out-of-trend event management through real-time monitoring.

Future Trends and Applications

Emerging developments include:

• Integration of method transfer into comprehensive Process Analytical Technology (PAT) frameworks for real-time quality assurance.
• Advanced chemometric and machine-learning algorithms to reduce transfer-related error propagation.
• Cloud-based calibration and model management platforms enabling collaborative updates and global deployment.
• Extension of transfer principles to other spectroscopic and multi-modal analytical techniques.

Conclusion

Structured transfer of NIR analytical methods enables laboratories to leverage existing models, adopt new instrumentation swiftly, and maintain consistent, regulatory-compliant quality control across diverse sites. Following a clear workflow—preparation, transfer, validation, update, and routine use—ensures reliable performance while optimizing resources.

References

1. Metrohm NIR Application Note AN-NIR-011, Calibration model transfer of caffeine on the NIRS XDS Rapid Content Analyzer.
2. Metrohm NIR Application Note AN-NIR-028, Data and method transfer from System II analyzer to Metrohm NIRS XDS or DS2500 analyzer.
3. Burns DA, Ciurczak EW. Handbook of Near-Infrared Analysis. 3rd ed. CRC Press; 2007.
4. Metrohm NIR Application Note AN-NIR-043, Analytical data transfer between a Fourier transform and a dispersive NIR instrument.
5. Metrohm White Paper WP-020, Near-infrared spectroscopy: Technology comparison.
6. United States Pharmacopeia USP 40, Chapters <1219>, <1224>, <1225>, <1226>; 2017.
7. European Pharmacopoeia 9th Edition; 2017.
8. ICH Q2(R1), Validation of Analytical Procedures: Text and Methodology; 1994.