Metrohm i-Raman EX Raman spectrometer

Importance of the Topic

The ability to perform high-quality Raman spectroscopy in the field or at point-of-use is essential for rapid material identification and quantitative analysis across diverse sectors such as pharmaceutical quality control, environmental monitoring, forensic screening and food safety. Conventional 785 nm Raman systems often suffer from sample autofluorescence that impedes detection of weak Raman signals. By exploiting a 1064 nm excitation source with advanced detector cooling and optical design, modern portable Raman instruments overcome fluorescence interference and deliver research-grade performance under real-world conditions.

Objectives and Study Overview

This article introduces a portable Raman spectrometer featuring a 1064 nm CleanLaze® laser, a deep-cooled InGaAs array detector and a high-throughput spectrograph. The goals are to demonstrate:

• Suppression of autofluorescence in colored and biological samples
• Broad fingerprint region coverage (100–2500 cm⁻¹)
• Quantitative and qualitative capabilities with integrated software
• Flexibility for solid, liquid and stand-off measurements via sampling accessories

Methodology and Instrumentation

The system employs a patented CleanLaze® 1064 nm laser for stable excitation and an InGaAs detector with deep TE cooling (–20 °C ± 2 °C) to minimize dark noise. A high-throughput spectrograph maximizes photon collection efficiency. Key hardware elements include:

• Fiber-optic probe with XYZ positioning stage
• Optional sampling accessories: cuvette and vial holders, flow cell, immersion probe, long-distance lenses and microscope adaptor
• Laser safety goggles and protective enclosure for sensitive measurements

Data acquisition and analysis are supported by:

• BWSpec® for instrument control, real-time peak analysis and trending
• Vision™ for method development, routine monitoring and performance checks
• BWIQ® multivariate software (PLS, PCA, SVM) for quantitative chemometric models
• BWID® for library-based material identification, including pharma-compliant workflows (FDA 21 CFR Part 11)

Main Results and Discussion

Demonstration spectra of cyclohexane (1 s integration) highlight the high signal-to-noise ratio and spectral resolution (< 10 cm⁻¹ at 1296 nm). A comparative study of sesame oil measured with 785 nm and 1064 nm excitation shows marked reduction of background fluorescence and clearer Raman features at 1064 nm. The broad 100–2500 cm⁻¹ range captures the full molecular fingerprint, enabling detection of subtle spectral differences in complex matrices.

Benefits and Practical Applications

The 1064 nm portable Raman platform offers several advantages:

• Reduced fluorescence interference for colored and biological samples
• Quantitative accuracy through chemometric algorithms and real-time feedback
• Rapid material screening for forensic, environmental, pharmaceutical and food sectors
• Field-deployable form factor with low power consumption and battery operation

Representative applications include narcotics identification, petrochemical analysis, bioscience diagnostics, explosives detection and polymer quality control.

Future Trends and Potential Applications

Advances in detector technology, multivariate algorithms and miniaturized lasers will further enhance sensitivity and reduce system size. Combined with cloud-based spectral libraries and AI-driven data interpretation, next-generation portable Raman spectrometers are poised for autonomous field deployment in environmental monitoring networks, on-site pharmaceutical verification and real-time process analytics. Stand-off measurement using long-distance optics and robotics integration will broaden applications in security and defense.

Conclusion

The described 1064 nm portable Raman spectrometer delivers fluorescence-free, research-grade performance in a compact, user-friendly package. Its broad spectral coverage, robust sampling accessories and comprehensive software suite facilitate qualitative and quantitative analyses across multiple industries. By minimizing autofluorescence and streamlining workflows, this platform fills a critical gap for reliable in-field Raman measurements.