Attenuated Total Reflectance – Fourier Transform Infrared Spectroscopy (ATR-FTIR)  is a technique used to detect the presence of functional groups on a surface. This surface sensitive form of infrared spectroscopy employs a Ge or ZnSe crystal to amplify the otherwise weak signal from surface compounds.  The small penetration depth of the infrared signal ensures that the technique is surface sensitive. 

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