GC and MS properties of β-blockers as tert-butyidimethylsilyl derivatives and as ethoxycarbonyl/trimethylsilyl derivatives

Fourteen beta-blockers in pre-dried free base forms were simultaneously converted into tert-butyldimethylsilyl (TBDMS) derivatives in one-step. As a different approach, beta-blockers were directly transformed into N-ethoxycarbonyl (EOC) derivatives in aqueous solution, followed by extraction and trimethylsilyl (TMS) derivatization. The retention index sets measured by DB-5 and DB-17 dual-column GC were characteristic for each beta-blocker as TBDMS- and EOC/TMS derivatives. Their characteristic fragmentation patterns obtained by GC-MS facilitated easier peak identification of each beta-blocker. The overall EOC/TMS method for assays of 14 beta-blockers in aqueous solution was linear with acceptable precision and accuracy.