FTIR - Fingerprint Spectrum

Fourier Transform Infrared Spectroscopy (FTIR) is a useful tool for identifying types of chemical bonds in a molecule by producing an infrared absorption spectrum that is like a molecular "fingerprint". The FTIR generates a spectrum of absorption bands between 4000 and 400 wavenumbers. Absorbances in the region between 4000 and 1500 are usually associated with functional organic groups such as hydroxyl (OH), carbonyl (C=O), amino (NH) or mercaptan (SH) etc. The fingerprint region of the spectrum lies between 1500 and 400 wavenumbers. Here, intra-molecular phenomena predominate that are highly specific for each material giving rise to unique spectra and a “fingerprint” useful for identification purposes. FTIR can be used to identify chemicals from spills, paints, polymers, coatings, drugs, and contaminants. Finger prints are useful forensically because there is easy online or reference text access to thousands of established FTIR scans for different materials. One can assess the presence of various ingredients in mixtures by comparing the FTIR references for candidate ingredients. Fingerprinting is also useful in verification and quality control of product or for reproducibility of new product design. Matching FTIR scans between lot numbers one is testimony that production is consistent.