Used primarily as a silylating agent in analytical chemistry, especially in gas chromatography (GC) and mass spectrometry (MS). It introduces trimethylsilyl groups to replace active hydrogens in compounds like alcohols, phenols, carboxylic acids, and amines. This derivatization improves volatility, thermal stability, and peak resolution, making polar compounds easier to analyze by GC-MS. Commonly applied in metabolite profiling, drug testing, and environmental analysis where detection of hydroxyl- or amino-containing molecules is required. Also used in organic synthesis to protect functional groups during multi-step reactions.