title: Fourier transform infrared imaging of human hair with a high spatial resolution without the use of a synchrotron.
abstract: The cross-section of a human hair has been imaged for the first time using the micro attenuated total reflection (ATR) Fourier transformed infrared (FT-IR) method in combination with a focal plane array (FPA) detector. A rigorous approach was applied to determine the spatial resolution, namely, measuring the distance over which the band absorbance changes from 95 to 5% of the maximum absorbance when passing through a sharp interface. The measured value for IR transmission was approximately 16 microm, while the value obtained using ATR imaging was approximately 5 microm. The enhanced spatial resolution achieved by this method allows the medulla of the hair (approximately 8 microm in diameter) to be imaged clearly without the need for a synchrotron source. The spatial resolution of transmission and ATR imaging is compared, and advantages of ATR imaging are discussed.
authors.affiliation: Department of Chemical Engineering and Chemical Technology, Imperial College London, South Kensington Campus, London SW7 2AZ, United Kingdom.
authors.forename: K L A
authors.initials: KL
authors.lastname: Chan
authors.forename: S G
authors.initials: SG
authors.lastname: Kazarian
authors.forename: A
authors.initials: A
authors.lastname: Mavraki
authors.forename: D R
authors.initials: DR
authors.lastname: Williams
mesh_terms: D000577:Amides / Q000032:analysis* / Q000737:chemistry*; D006197:Hair / Q000737:chemistry* / Q000166:cytology*; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D017356:Synchrotrons
chemical_list: D000577:Amides