Synchronized variation of source conditions of a chemical ionization mass spectrometer at atmospheric pressure coupled to a chromatograph to improve stability during analysis

摘要

A mass spectrometer comprising: a gas chromatography separation device; an atmospheric pressure ionization ion source including an atmospheric pressure chemical ionization ("APCI") ionization source having a corona discharge device for ionizing analytes; anda control system configured and adapted to: (i) operate the atmospheric pressure ionization ion source at a first corona current for a first period of time while one or more solvents elute from the gas chromatography separation device during a solvent front; and then (ii) operating the atmospheric pressure ionization ion source at a second different corona current for a second subsequent period of time while one or more analytes elute from the gas chromatography separation device.