Method of operating an ion trap mass spectrometer

Abstract From the Canadian patent

A method is disclosed for ins ineasing the dynamic range and sensitivity of a quadrupole ion trap mass spectrometer operating in the chemical ionization mode. Prior to mass analysis, a prescan is performed with the ion trap and the ionization and reaction periods are adjusted to produce enough stored product or analyte ions to generate a good signal-to-noise ratio in the detection of trace amounts of analyte yet not so many analyte ions that resolution in the mass spectrum is lost. A mass analysis scan is then performed with the ion trap using the ionization and reaction periods pre-determined during the prescan.