DETERMINATION OF ACIDIC AND BASIC NEUTRAL PESTICIDES IN WATER WITH A NEW MICROLITER FLOW-RATE LC/MS PARTICLE-BEAM INTERFACE

A new method for the determination of 32 base/neutral and 13 acidic pesticides in water, which has been proven to be particularly amenable to high-performance liquid chromatography, is discussed. A liquid/solid extraction procedure for the isolation of pesticides from aqueous samples is employed. The LC/MS analysis is carried out with a LC-18 reversed-phase packed capillary column coupled with a Hewlett-Packard 5989A quadrupole mass spectrometer using a new microliter flow rate particle beam interface. Mobile-phase flow rates, ranging between 1 and 5 mu L/min, pass into the electron impact ion source of the mass spectrometer. The aerosol generated by the reduced solvent imput allows improved signal response for high water content mobile phases with better chromatographic performance during gradient analyses. Reliable and reproducible results for positive identification and quantitation of target analytes are presented. The very low contamination of the instrument satisfies the continuous use demands of routine analysis.