MASS-TRANSPORT AND CALIBRATION IN LIQUID-CHROMATOGRAPHY PARTICLE BEAM MASS-SPECTROMETRY

Differences in the designs of two liquid chromatography particle beam mass spectrometry systems result in differences in the transport of ammonium acetate and differences in ion abundance-enhancing carrier effects. The effect of mobile phase composition, especially the, proportion of water in the mobile phase, on transport efficiency is described. Instrument detection limits for 12 compounds with two different interface designs are presented. The calibrations are generally nonlinear explained in terms of mass transport effects and supported by experiments with isotopically labeled species that coelute with the native species. Summary results of a small multilaboratory study are presented. Calibration with isotopically labeled internal standards is recommended for real-world environmental samples.