Comparison of FT-IR and Raman Spectroscopy

Identification of common chemicals in safety and security applications

Description: The study compares using Raman and IR spectroscopy for the characterization and identification of common materials found in safety & security applications.

Correct and timely identification of chemicals and chemical compounds are required to ensure safety. In this work, a comparison of two proven techniques is performed on a set of chemicals considered “materials of interest” in safety and security applications.

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Introduction: FT-IR and Raman are proven optical-based techniques used to identify a variety of chemical substances and compounds in a number industries. Sometimes used as complimentary technologies, each provide benefits and advantages. However for safety and security applications, FT-IR has often been regarded as the most effective analytical technique for identification of many chemical substances and compounds. In comparison, Raman has not been considered as a technically equal or superior method for identification or verification purposes. Since these previous studies had focused on 785 nm Raman instruments, we decided to expand the study and compare the 785 nm Raman and the Progeny™ ResQ™ 1064 nm Raman analyzer with FT-IR results. The scope of the study involved analyses of common household chemical substances, specifically those sold as consumer goods but also utilized as clandestine laboratory materials. By themselves these chemicals may be innocuous, but are frequently used in combination to manufacture compounds that pose a threat to public, response team, and environmental safety. A variety of chemical types were selected, with a focus on materials considered best suited for FT-IR (Fourier transform infra-red). Approximately 60 materials were evaluated covering materials from acids/bases, over-the-counter (OTC) products, fuels, biologicals and proteins, organic and inorganic salts and a catch-all category for miscellaneous household chemicals commonly found in a basement or garage. The expanded test set provided a better representative sample of chemicals commonly found in a household, yet potentially used in a clandestine lab.