Contactless Material Verification and Identification

Significance of Topic

The rapid, non-invasive identification of materials directly at the point of need offers significant advantages in quality control, customs inspection, and hazardous substance screening. Handheld Raman spectroscopy enables contactless analysis through packaging, minimizing sample handling, reducing contamination risk, and ensuring operator safety. This capability supports 100 % inspection rates and immediate decision making, aligning with regulatory requirements such as cGMP and 21 CFR Part 11 for data integrity.

Objectives and Overview of the Study

This product note presents the performance and practical capabilities of the BRAVO handheld Raman spectrometer for through-barrier material verification and identification. Key aims include demonstrating:

• Material identification and verification workflows in situ.
• Performance of DuoLaser™ excitation across 300–3200 cm⁻¹.
• Fluorescence mitigation via SSETM.
• Analysis efficiency through common packaging types.

Methodology and Instrumentation

Measurements were conducted using the BRAVO handheld Raman spectrometer, featuring:

• DuoLaser™ excitation sources at 785 nm and 1064 nm covering fingerprint and CH-stretching regions.
• Fluorescence suppression technology (SSETM) for enhanced spectral clarity.
• Wavenumber accuracy of ±1 cm⁻¹ (fingerprint) and ±2 cm⁻¹ (CH-stretch).
• Laser Class 1M with output power below 100 mW for user safety.
• Remote control via Wi-Fi or Ethernet.

Custom measurement tips were used to adjust focus position for films, vials, and thicker barriers up to several millimeters.

Main Results and Discussion

Analysis through amber glass showed severe signal loss due to absorption: approximately 95 % loss at 785 nm and 98 % at 1064 nm for a 3 L amber bottle. This absorption prolongs measurement times significantly, making routine use on dark, thick glass impractical. In contrast, clear packaging permits nearly unchanged transmission of laser and Raman signals. By optimizing the focus with dedicated film tips, the BRAVO instrument successfully acquired spectra of talc through heavy polyethylene bags, using material-specific spectral ranges to exclude polymer signals. In addition, a variable-focus tip enabled the acquisition of 1-hexanol spectra through a 2.5 L amber bottle, matching results from a clear vial but requiring 12× longer acquisition due to absorption.
Fluorescent background from glass bottles was effectively removed by SSETM processing. Sequential excitation measurements at shifted wavelengths extracted pure Raman signatures even in the presence of intense fluorescence.

Benefits and Practical Applications

Key advantages of the BRAVO handheld Raman system include:

• Non-destructive, through-barrier analysis reducing sample handling and contamination risk.
• Immediate results for customs, incoming goods inspection, and hazardous material screening.
• High sensitivity and selectivity across a wide spectral range.
• Automated fluorescence mitigation ensuring robust identification in challenging matrices.
• Compliance with pharmaceutical data integrity standards.

Future Trends and Applications

Advancements may focus on:

• Enhanced tip designs for deeper penetration and broader barrier compatibility.
• Integration of machine-learning algorithms for automated spectrum interpretation.
• Extended spectral coverage and miniaturization of multi-modal handheld devices.
• Field-deployable remote sensing networks for real-time material surveillance.

Conclusion

The BRAVO handheld Raman spectrometer delivers laboratory-quality, contactless material verification through packaging, balancing sensitivity, safety, and ease of use. While dark and thick barriers limit routine throughput, clear and thin packaging applications excel. SSETM fluorescence mitigation and adaptable measurement tips extend applicability across diverse scenarios, supporting rapid in-field decision making under regulatory frameworks.

References

[1] Bruker Product Note T30 03/16, Accuracy is crucial: The starting point for a robust transfer of methods
[2] Bruker Product Note R34 05/16, Advanced Data Acquisition and Evaluation in Handheld Raman Spectroscopy
[3] Bruker Product Note T29 12/15, Efficient mitigation of fluorescence in Raman spectroscopy using SSETM