DETERMINATION OF CARBOFURAN BY ONLINE IMMUNOAFFINITY CHROMATOGRAPHY WITH COUPLED-COLUMN LIQUID-CHROMATOGRAPHY MASS-SPECTROMETRY

Development of a new technology for combined on-line sample preparatio n and analyte confirmation is presented. This technology involves the use of antibodies for trace analyte extraction and enrichment directly from a complex matrix. The antibodies are used in columns designed fo r use with ordinary high-pressure liquid chromatographic equipment. Th e immunoaffinity columns are combined with conventional reversed-phase LC columns by use of column-switching techniques and coupled directly to an atmospheric pressure ionization quadrupole ion trap mass spectr ometer equipped with a pneumatically assisted electrospray (ion spray) interface. A column of aldehyde-activated silica was used to prepare a column specific to carbofuran. This column demonstrated excellent sp ecificity toward carbofuran and showed no binding of another, unrelate d compound, fluometuron. Direct extraction and detection of carbofuran was demonstrated at low levels (40 pg/mL) in spiked water, but the re al utility of immunoaffinity chromatography (IAC) is demonstrated by t he on-line extraction and detection of carbofuran from a chemically co mplex, crude potato extract. Samples extracted using an IAC column ind icate that superior purification is obtained with IAC in comparison wi th samples pumped directly onto a reversed-phase trapping column. A de tection limit for carbofuran of approximately 2.5 ng/g of potato was o btained using an atmospheric pressure ionization quadrupole ion trap m ass spectrometer.