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 pe sticides in water, which has been proven to be particularly amenable t o high-performance liquid chromatography, is discussed. A liquid/solid extraction procedure for the isolation of pesticides from aqueous sam ples is employed. The LC/MS analysis is carried out with a LC-18 rever sed-phase packed capillary column coupled with a Hewlett-Packard 5989A quadrupole mass spectrometer using a new microliter flow rate particl e beam interface. Mobile-phase flow rates, ranging between 1 and 5 mu L/min, pass into the electron impact ion source of the mass spectromet er. The aerosol generated by the reduced solvent imput allows improved signal response for high water content mobile phases with better chro matographic performance during gradient analyses. Reliable and reprodu cible results for positive identification and quantitation of target a nalytes are presented. The very low contamination of the instrument sa tisfies the continuous use demands of routine analysis.