Used for blocking and protection of hydroxyl groups in natural products, e.g. amino acids, carbohydrates; Used for blocking and protection of functional groups in organic intermediates; Used for formation of derivatives of H-acid compounds for analysis; The silylated derivatives are volatile and can therefore be determined by gas chromatography. Deblocking is preferably carried out by means of hydrolysis, giving high yields. In some cases, thermal elimination of the trimethylsilyl group is possible.