MSTFA is an effective trimethylsilyl (TMS) donor. MSTFA reacts
to replace labile hydrogens on a wide range of polar compounds
with a TMS group and is used to prepare volatile and thermally stable
derivatives for GC–MS [17] To increase the performance of the
gas chromatographic separation, metoprolol and IS were derivatized
using MSTFA (Fig. 1). The secondary amine (–NH) and hydroxy
(–OH) groups were converted to the corresponding silyl (–N-TMS)
and (–O-TMS) groups.