Ahura Scientific shows handheld FTIR chemical identification device

Published 12 February 2008

First responders — but also those in charge of chemical clean-ups, quality control, product verification, raw material inspection, pharmaceutical manufacturing, food production, petrochemical processing, and composite analysis — would welcome this small, light chemical identifier

Wilmington, Massachusetts-based Ahura Scientific, a specialist in handheld systems for chemical identification, launched its new FTIR (Fourier-Transform Infrared) platform with the introduction of TruDefender FT, a three-pound handheld FTIR system for field-based chemical identification. TruDefender FT is optimized for hazmat and military applications, an it allows first responders to analyze — and act on the information gained from the analysis — quickly.

FTIR spectroscopy is an technique for chemical identification suitable for many industries, including public safety applications like hazmat response. Ahura, building on its work in handheld Raman spectroscopy, recognized FTIR’s promise and developed a compact, easy-to-use FTIR system designed to the same standards as the company’s FirstDefender. The launch of the FTIR platform proves the company’s ability to leverage different molecular spectroscopy methods to support different applications and markets. The company says that in addition to the safety and security market, the new FTIR platform can be applied to a range of quality control (QC), product verification, and raw material inspection applications in the industrial sector, including pharmaceutical manufacturing, food production, petrochemical processing, and composite analysis. “Timely and accurate substance identification in the field is critical,” said Matthew Farr, senior homeland security analyst at Frost & Sullivan. “A rugged, handheld and user-friendly FTIR device has the potential to revolutionize the way first responders identify and analyze substances in the field, greatly improving their decision-making capabilities.”

Two of the widely adopted technologies for identification of unknown solids and liquids are Raman and FTIR spectroscopy. The strength with which a substance responds to each technology is dictated by its unique molecular structure, with some responding well to FTIR analysis, and others better suited to Raman. TruDefender FT complements Ahura Scientific’s FirstDefender Raman instrument to maximize coverage of unknown substances. “TruDefender FT is a sophisticated FTIR system that literally fits in the palm of the hand,” said Doug Kahn, chairman and CEO of Ahura Scientific. “Our goal with TruDefender FT was to make it as robust and easy-to-use as possible, while maintaining the product accuracy and portability our customers have come to expect from Ahura Scientific.”

How it works

FTIR spectroscopy

FTIR (Fourier Transform Infrared) spectroscopy, or FTIR analysis, is a failure analysis technique which provides information about the chemical bonding or molecular structure of organic or inorganic materials. It is used in failure analysis to identify unknown materials present in a specimen, and is usually conducted to complement EDX analysis. The technique exploits the fact that bonds and groups of bonds vibrate at characteristic frequencies. A molecule which is exposed to infrared rays absorbs infrared energy at frequencies which are characteristic to that molecule. During FTIR analysis, a spot on the specimen is subjected to a modulated IR beam. The specimen’s transmittance and reflectance of the infrared rays at different frequencies is translated into an IR absorption plot consisting of reverse peaks. The resulting FTIR spectral pattern is then analyzed and matched with known signatures of identified materials in the FTIR library.

Unlike Scanning Electron Microscopy (SEM) inspection or Energy Dispersive X-ray (EDX) analysis, FTIR spectroscopy does not require a vacuum, since neither oxygen nor nitrogen absorb infrared rays. FTIR analysis can be applied to minute quantities of solid, liquid, or gaseous materials. When the library of FTIR spectral patterns does not provide an acceptable match, individual peaks in the FTIR plot may be used to yield partial information about the specimen. Single fibers or particles are sufficient for material identification through FTIR analysis. Organic contaminants in solvents may also be analyzed by first separating the mixture into its components by gas chromatography, and then analyzing each component by FTIR.

Raman spectroscopy

The Raman effect occurs when incident light excites molecules in a sample which subsequently scatters the light. Most of this scattered light is at the same wavelength as the incident light, but some is scattered at a different wavelength. This inelastically scattered light is called Raman scatter. It results from the molecule changing its molecular motions. The energy difference between the incident light (Ei) and the Raman scattered light (Es) is equal to the energy involved in changing the molecule’s vibrational state (that is, getting the molecule to vibrate, Ev). This energy difference is called the Raman shift.

Ev = Ei - Es

Several different Raman shifted signals will often be observed, each being associated with different vibrational or rotational motions of molecules in the sample. The particular molecule and its environment will determine what Raman signals will be observed. A plot of Raman intensity vs. Raman shift is a Raman spectrum.