TMS-250 is exhaustively and repeatedly reacted with trimethyl silyl groups. Standard nomenclature designates the bonded phase as C1. This wide-pore column is recommended for the analysis of proteins. On TSKgel TMS-250 proteins show sharper peaks than on ohter wide-pore C8 or C18 columns. It can accommodate even large proteins, such as aldolase (158 kDa).