Accurate mass measurement using multiple sprayer nano-electrospray mass spectrometry combined with nano-scale high-performance liquid chromatography on a magnetic sector instrument

A new technique for accurate mass measurement utilizing multiple sprayer nano-electrospray ionization mass spectrometry (nano-ESI-MS) combined with nano-scale high-performance liquid chromatography (nano-HPLC) on a magnetic sector instrument is described. Both metal-coated glass capillaries and fused-silica capillaries were used as nano-ESI sprayers. A metal-coated glass capillary was used for the introduction of the Ref. compound solution, and a metal-coated fused-silica capillary was used for connection to the nano-HPLC column. By shifting each sprayer’s position relative to the sampling orifice, spectra were obtained of both the sample components as eluted from the column and reference compounds. Several standard compounds were examined and satisfactory accurate masses were obtained. Problems arising from differences in ionization efficiency between the sample and reference compounds were not observed.