Abstract
Sensitive analytical method of N-butylscopolammonium bromide (NBS) using LC-ESI/MS was developed and applied to determine a plasma concentration and urinary excretion of NBS. In ESI/MS intact molecular cation of NBS, quaternary ammonium salt, sensitively appeared as a base peak. NBS in plasma was effectively extracted and purified by Bond Elut C18, and determined by a semimicro-LC-ESI/MS equipped with on-line concentration system. NBS-d9 was synthesized and used as an internal standard. Sensitivity was compared with selected ion monitoring (SIM) and selected reaction monitoring (SRM). In this case SIM was higher sensitive than SRM. The quantitation limit for this method was determined to be 4 pg per 1 mL plasma. The inter-assay precision was less than 11% (RSD). Plasma concentration of NBS in human was detectable for the first time by this method.
