Verifying Raw Materials by Spatially Offset Raman Spectroscopy

Importance of the Topic

Spatially offset Raman spectroscopy (SORS) addresses critical needs in pharmaceutical quality control by enabling noninvasive and rapid verification of raw materials through opaque or fluorescent packaging. This approach reduces errors, minimizes contamination risk, and streamlines warehouse operations.

Objectives and Study Overview

This technical overview describes the Agilent RapID Raman system’s implementation of SORS for raw material identity verification (RMID). It outlines the workflow from building a tailored spectral library to routine production testing, emphasizing speed, accuracy, and operational efficiency.

Methodology and Used Instrumentation

• Principles of SORS: Two Raman spectra are acquired—one at zero spatial offset and one at an offset. A scaled subtraction removes the container background, isolating the sample spectrum for comparison.
• Library Development: Reference spectra are collected through the original packaging at several positions. Software constructs, validates, and crosschecks the model before release into production.

Used Instrumentation

• Agilent RapID Raman system
• 785 nm laser excitation and CCD detector
• Integrated barcode scanner on the probe head
• Software suite for spectral subtraction, model building, validation, and LIMS integration

Main Results and Discussion

SORS produced high-quality spectra of sucrose inside a 1.5 mm thick polypropylene container, where conventional Raman failed. Each measurement requires approximately 8–10 seconds. In a typical warehouse setting, 100 sacks can be verified in under 30 minutes, with immediate pass/fail feedback and automated batch report generation.

Benefits and Practical Applications

• Noninvasive testing through opaque or multilayered packaging
• Elimination of container opening, powder handling, and associated safety precautions
• High throughput suitable for large-scale raw material intake
• Seamless data output to networked systems or LIMS

Future Trends and Opportunities

Emerging developments may include expanded SORS libraries covering diverse container types, real-time inline implementation for continuous manufacturing, advanced chemometric and AI-driven spectral interpretation for complex mixtures, and miniaturized handheld devices for field use.

Conclusion

The Agilent RapID Raman system employing SORS delivers a robust, fast, and noninvasive solution for raw material identity verification, significantly enhancing pharmaceutical QC workflows and reducing operational costs.

Reference

• Agilent Technologies. Verifying Raw Materials by Spatially Offset Raman Spectroscopy. Technical Overview. 2018.