Analysis of human hair by ATR FT-IR microspectroscopy

Abstract

Homemade slide-on Ge [micro]IRE accessory was designed for analysis of small amount sample. The accessory was employed for ATR FT-IR spectral acquisition of single human hair by using an infrared microscope. The spectrum acquired by the slide-on Ge [micro]IRE was similar to those acquired by conventional ATR technique (Hemispherical Ge IRE). The spectral intensity of single human hair acquired by slide-on Ge [micro]IRE is higher than the spectrum acquired by conventional ATR technique. Due to the small contract area of the [micro]IRE is les than 100x100 [micro]m[superscript 2], the small amount sample could be analyzed without an additional sample preparation. The analysis takes only a short time while the results are accurate and reliable. The observed spectra shows the different spectrum between untreated-hair and chemical treated-hair, un-split and split hairs, and the different type of cosmetics on hair surface. The observed spectra were directly associated with molecular changes occurring at the molecular level. The results can be applied for forensic analysis.