Analysis of Cosmetic Residues on a Single Human Hair by ATR FT-IR Microspectroscopy

The study demonstrated that ATR FT-IR microspectroscopy, using a homemade slide-on Ge μIRE accessory, was an effective tool for characterizing single human hairs and their surfaces. This technique provided detailed chemical information about the molecular structure of hair, including the presence of proteins, water, lipids, and waxes. The method was non-destructive, required no complicated sample preparation, and had a short analysis time, making it suitable for forensic and cosmetic applications. The research was supported by various Thai research funds and Chulalongkorn University.