See-through ID with Raman technology

Importance of the Topic

Raman spectroscopy is a critical tool for rapid, nondestructive chemical identification across scientific, medical, and security fields. Traditional Raman methods require direct access or transparent barriers, limiting on-site applications. See-through Raman (ST) with 1064 nm excitation overcomes these restrictions by enabling identification through opaque packaging, enhancing safety and operational speed for first responders, customs agents, and quality control professionals.

Objectives and Study Overview

This application note demonstrates the performance of the Metrohm TacticID-1064ST handheld Raman analyzer equipped with ST technology. Key goals include:

• Verifying identification through common opaque containers such as white polyethylene bottles, paper sacks, envelopes, and coated tablets.
• Comparing ST performance at 1064 nm with standard Raman configurations.
• Evaluating detection of low-scattering substances like trisodium phosphate through multilayer packaging.

Methodology and Instrumentation

The TacticID-1064ST integrates a 1064 nm laser and a see-through adapter to collect Raman spectra from samples inside opaque materials. Its larger sampling area reduces power density, minimizing sample damage and improving detection of heterogeneous mixtures. Advanced algorithms remove container contributions, enabling accurate library matching. Tests covered:

• White and colored plastic bottles
• Multi-layer kraft paper sacks with plastic lining
• Envelopes and coated tablet surfaces

Main Results and Discussion

ST technology successfully identified sodium benzoate inside white polyethylene bottles, demonstrating clear spectral peaks despite container interference. Coated tablets with dark surfaces yielded distinctive Raman signatures of the core material. A series of pharmaceutical excipients (calcium carbonate, dextrin, α-cyclodextrin, d-maltose, and trisodium phosphate) were tested through various paper bag combinations. Even trisodium phosphate, a weak Raman scatterer, achieved hit quality indices above 88 through multilayer kraft sacks, outperforming 785 nm excitation, which failed in comparable tests.

Key findings from Table 1:

• All five substances showed HQI values >90 through two-layer white paper and mixed kraft layers.
• Trisodium phosphate identification reached HQI 88–93 depending on layer composition.
• White kraft with plastic or fiber layers still permitted reliable detection.

Benefits and Practical Applications

Through-package Raman identification offers multiple advantages:

• Eliminates direct contact with unknown or hazardous samples.
• Enables rapid field screening for law enforcement, customs, and hazmat teams.
• Supports quality assurance of raw materials in pharmaceutical and chemical industries.
• Expands Raman applicability to previously inaccessible sample formats.

Future Trends and Potential Applications

Advancements in ST Raman may lead to:

• Integration with automated inspection systems in warehouses and shipping facilities.
• Enhanced algorithms for complex mixtures and real-time database updates via cloud connectivity.
• Miniaturized, handheld devices with extended battery life and environmental sealing for harsh field conditions.
• Expanded libraries covering emerging threats and novel materials.

Conclusion

The Metrohm TacticID-1064ST with see-through Raman technology provides a robust solution for nondestructive chemical identification through opaque containers. Its ability to deliver high-quality spectra and accurate library matching—even for low-scattering compounds inside multilayer packaging—broadens Raman spectroscopy’s applicability in field operations and industrial quality control.

References

No external literature references were provided in the source document.