Metrohm i-Raman EX Raman spectrometer

Significance of the Topic

The ability to perform high‐quality Raman analysis in a portable format expands analytical capabilities beyond the laboratory, supporting on‐site investigations in fields such as forensics, environmental monitoring, pharmaceutical quality control, and agricultural testing. The use of a 1064 nm excitation source significantly reduces fluorescence interference, enabling clear spectral acquisition from colored or biologically relevant samples.

Objectives and Study Overview

This whitepaper presents the design and performance characteristics of the i-RAMAN® EX portable Raman spectrometer. Key aims include demonstrating:

• Fluorescence mitigation with 1064 nm CleanLaze® excitation.
• High‐throughput, high signal‐to‐noise detection across 100–2500 cm^–1.
• Quantitative and qualitative analysis capabilities using integrated software suites.

Methodology and Instrumentation

The i-RAMAN® EX employs:

• 1064 nm CleanLaze® excitation laser (nominal 330 mW at probe, 430 mW at laser port) with adjustable power control.
• TE‐cooled InGaAs array detector (–20 °C ± 2 °C) in a high‐throughput spectrograph, delivering < 10 cm^–1 resolution at 1296 nm.
• Fiber‐optic Raman probe with XYZ positioning stage; a variety of sampling accessories for solids, liquids, cuvettes, flow cells and stand‐off measurement lenses.
• Power via AC adaptor (100–240 VAC input) or optional battery for true portability.

Software packages:

• BWSpec® for instrument control and real‐time peak analysis.
• BWID® for rapid library‐based identification with FDA 21 CFR Part 11 compliance in regulated environments.
• BWIQ® for multivariate calibration and chemometric methods (PLS, PCA, SVM).
• Vision for unified control, method building, and routine analysis.

Main Results and Discussion

Tests with cyclohexane demonstrated excellent signal‐to‐noise ratio even at one‐second integration, reflecting high spectrograph throughput. Comparative measurements of sesame oil using 785 nm versus 1064 nm excitation highlighted the significant reduction of autofluorescence at the longer wavelength, preserving spectral fidelity in the fingerprint region.

Benefits and Practical Applications

The i-RAMAN EX system offers:

• Laboratory‐grade Raman performance in a lightweight, field‐deployable instrument.
• Fluorescence‐free spectra enabling analyses of biological samples, natural products, and colored materials.
• Comprehensive quantitative workflows via Vision and BWIQ, supporting multivariate analysis for complex mixtures.
• Applications spanning forensic narcotics detection, environmental monitoring, pharmaceutical material verification, food quality assessment, and more.

Future Trends and Potential Uses

Emerging developments are likely to include:

• Integration of artificial intelligence for automated spectral interpretation and anomaly detection.
• Advancements in stand‐off Raman for remote sensing of hazardous or inaccessible targets.
• Miniaturization of detectors and optics for ultra‐portable, wearable Raman devices.
• Expanded chemometric toolkits for real‐time, in‐field decision support across industries.

Conclusion

The i-RAMAN EX combines advanced laser stabilization, deep‐cooled InGaAs detection, and versatile sampling accessories to deliver high‐quality, fluorescence‐free Raman spectra in a portable format. Its robust software ecosystem ensures both qualitative identification and quantitative multivariate analysis, making it a valuable tool for a wide range of field and laboratory applications.

Instrumentation Used

• i‐RAMAN EX portable Raman spectrometer (Model BWS485III).
• 1064 nm CleanLaze® excitation laser.
• TE‐cooled InGaAs array detector.
• Fiber‐optic Raman probe and XYZ stage.
• Accessory set: cuvette holder, immersion probe, microscope adapter, flow cell enclosure, stand‐off lenses.