Gas chromatography (GC) is widely used as an analytical method that vaporizes samples without thermal decomposition. This property lends to GC analysis being adequate for the analysis of volatile samples; however, GC analysis has various limitations when analyzing nonvolatile or thermally unstable samples. GC silylation reagents are useful for introducing thermally stable and volatile organosilyl groups onto samples, and are applicable in GC analysis. Various trimethylsilylation reagents are available and can be readily selected based on a substrates structural features and functional groups present. In addition, five TCI products A5601, A5602, A5603, A5604, and A5605 are used as specialty trimethylsilylation reagents for micro- and high sensitivity analysis required under strict quality control measures. Each these trimethylsilylation reagents contain high-boiling-point impurities with retention index over 1500 is controlled below 50ppm by purification methods.