ZINC SELENIDE ATR ACCESSORY FOR THE AGILENT CARY 630 FTIR

Importance of the Topic

The use of attenuated total reflectance (ATR) in infrared spectroscopy has become ubiquitous in analytical laboratories due to its minimal sample preparation, rapid data acquisition, and ability to handle solids, liquids, and gels. The Agilent Zinc Selenide (ZnSe) ATR accessory paired with the Cary 630 FTIR delivers enhanced sensitivity and throughput, addressing growing demands for faster, more reliable detection of trace components in research, quality control, and industrial applications.

Objectives and Study Overview

This application note evaluates the design and performance of the Agilent single‐reflection ZnSe ATR accessory integrated with the Cary 630 FTIR. It aims to demonstrate how the unique optical configuration improves energy throughput, lowers noise, and accelerates data collection compared to conventional ATR systems. The note also outlines recommended use cases and compares short‐pathlength ATR sampling with variable‐pathlength accessories.

Methodology and Instrumentation

The ZnSe ATR accessory is engineered for seamless coupling with the Cary 630 FTIR, featuring a single‐bounce crystal at a nominal 45° incidence angle and a slip‐clutch pressure clamp to ensure consistent contact. Key specifications include:

• Crystal material: Zinc Selenide
• Effective penetration depths: ~1.1 µm at 4000 cm⁻¹, ~2.6 µm at 1700 cm⁻¹, and ~7.3 µm at 600 cm⁻¹
• Spectral range: 5100 to 600 cm⁻¹ (mid-IR)
• Dimensions: 9.2 × 8.9 cm footprint, 0.9 kg weight
• Software: Multilanguage guided workflows, color‐coded alerts, and automated cleaning prompts

The Cary 630 FTIR features a rugged, field-proven interferometer design optimized for mobile and laboratory use, with optional ZnSe windows for maximum throughput.

Main Results and Discussion

Performance testing shows that the ZnSe ATR accessory delivers superior signal-to-noise ratios and faster scan rates, enabling quantitative detection limits below those of traditional multi-reflection ATR systems. The wide transmission window of the ZnSe crystal ensures full spectral coverage for common organic and inorganic analytes. The built-in pressure mechanism yields highly reproducible spectra, even in humid or harsh environments.

Benefits and Practical Applications

The ZnSe ATR accessory offers several practical advantages:

• Rapid sample changeover without realignment
• High sensitivity for both solids and liquids at short pathlengths (1–7 µm)
• Compact footprint ideal for space-limited labs
• Robust performance under field and QC conditions
• Seamless interchange with DialPath/TumblIR for longer pathlength needs (≥30 µm) or Ge ATR for specialized applications

This flexibility makes it suitable for routine identification, validation, and QA/QC tasks across pharmaceuticals, polymers, chemicals, and environmental samples.

Future Trends and Applications

Advances in FTIR accessory design are trending toward modular, interchangeable platforms that cover pathlengths from 1 to 1000 µm. Integration with automated sampling and remote monitoring will further enhance throughput and reproducibility. Emerging fields such as in-line process analytics and microscale reaction monitoring will benefit from compact, high-throughput ATR accessories.

Conclusion

The Agilent ZnSe single-reflection ATR accessory combined with the Cary 630 FTIR provides a high-performance, easy-to-use solution for rapid IR analysis of solids and liquids. Its superior energy throughput, reproducible pressure control, and broad spectral range meet the demands of modern analytical laboratories, offering a versatile platform that can be expanded with complementary accessories for a complete FTIR solution.

References

Agilent Technologies, Inc. (2016) Zinc Selenide ATR Accessory for the Agilent Cary 630 FTIR, Publication 5991-6930EN.