Attenuated Total Reflectance

Attenuated Total Reflectance (ATR) is a technique used in infrared spectroscopy to analyze the surface of materials. It involves pressing a crystal with a high refractive index against the sample. Infrared light passes through the crystal and reflects internally; however, some energy extends slightly beyond the crystal surface into the sample. This interaction causes absorption of specific wavelengths, revealing the sample's molecular makeup. ATR allows for quick, direct analysis of solids, liquids, or powders without complex sample preparation, making it a valuable tool in laboratories for identifying chemical compositions efficiently.