Abstract: On a unit mass resolution mass spectrometer, such as a single quadrupole MS, allowing for only rough mass confirmation for qualitative analysis. In this study, a novel mass spectral calibration technique, MSIntegnityTM implemented in MassWorksTM, is introduced to externally calibrated using a unique procedure that corrects for both mass axis and mass spectral peak shape to facilitate pesticides identi?cation with high mass accuracy, MS data were acquired in pro?le mode on a unit mass resolution single-quadrupole instrument, even at such a unit mass resolution on a true chromatographic time scale, will now enable the elemental composition determination of unknown ions or ion fragments using a conventional mass spectrometer. This identification capability is further enhanced by a uniquely accurate approach for elemental composition determination through the use of isotope distribution information, CLIPSTM.

Key words: Accurate mass, Elemental composition, MassWorks, Ion fragmentation mechanism, Pesticides.