Metrohm i-Raman EX Raman spectrometer

Importance of the Topic

The i-RAMAN® EX represents a significant advancement in portable Raman spectroscopy by combining a 1064 nm CleanLaze® excitation laser with a TE-cooled InGaAs detector. This configuration effectively suppresses autofluorescence and expands analytical capabilities for diverse samples ranging from natural products and biological cultures to colored industrial materials. Its portability and low power requirements enable in-field, real-time qualitative and quantitative measurements that were previously only achievable with benchtop instruments.

Objectives and Study Overview

This whitepaper describes the design, performance, and application potential of the i-RAMAN EX. Key objectives include:

• Demonstrating fluorescence-free Raman measurement across the 100–2500 cm−1 range.
• Characterizing signal-to-noise performance and spectral resolution under field conditions.
• Showcasing software-driven qualitative and quantitative workflows for regulated and research environments.
• Outlining accessory compatibility for flexible sampling formats.

Methodology and Instrumentation

The i-RAMAN EX integrates:

• CleanLaze® 1064 nm excitation laser (330–430 mW) for minimized background fluorescence.
• High-throughput spectrograph optimized for rapid signal collection.
• Deeply TE-cooled InGaAs array detector (operating at −20 °C) offering high dynamic range.
• Spectral coverage from 100 to 2500 cm−1 with <10 cm−1 resolution at 1296 nm (ASTM E2529-06).
• Fiber-optic probe and XYZ-stage holder with optional cuvette, vial, flow cell, microscope and long-distance lens accessories.
• USB 2.0/1.1 computer interface and optional battery operation for true portability.

Main Results and Discussion

Experimental evaluations highlighted the system’s ability to capture high-quality Raman spectra with one-second integration times, illustrated by cyclohexane spectral acquisition showing excellent signal-to-noise. A comparative study of sesame oil spectra acquired at 785 nm versus 1064 nm confirmed the latter’s superior fluorescence suppression. The platform consistently resolved fingerprint-region features critical for compound identification and concentration analysis.

Software performance was validated through:

1. Real-time peak analysis and trend monitoring using BWSpec®.
2. Rapid library-based identification with BWID® (including Pharma-grade, 21 CFR Part 11 compliance).
3. Multivariate chemometric modeling (PLS, PCA, SVM) for quantitative predictions in Vision and BWIQ®.

Benefits and Practical Applications

The i-RAMAN EX offers:

• Fluorescence-free Raman detection ideal for pigments, biologics, and complex matrices.
• Portable form factor (17 cm × 34 cm × 28 cm, 3.4 kg) with low power draw for field or lab deployment.
• Versatile sampling via interchangeable probes and accessories.
• User-friendly software ecosystem enabling regulated environment compliance and advanced chemometric analysis.
• Applications spanning forensic narcotics, environmental monitoring, chemical warfare detection, pharmaceutical QC, food authenticity, polymer analysis, and biomedical diagnostics.

Future Trends and Possibilities

Emerging directions include:

• Integration with machine learning for automated spectral interpretation and anomaly detection.
• Miniaturized multimodal platforms combining Raman with infrared or fluorescence sensors.
• Cloud-based data management and remote instrument monitoring for distributed networks.
• Expanded spectral libraries and real-time adaptive algorithms for on-the-fly analysis in harsh or regulated environments.

Conclusion

The i-RAMAN EX combines high-performance 1064 nm Raman spectroscopy with rugged portability and a comprehensive software suite. It delivers fluorescence-free spectral data across the fingerprint region, enabling both qualitative identification and quantitative analysis in diverse application areas. Its modular design and accessory compatibility make it a versatile tool for laboratory research, industrial QA/QC, and in-field investigations.