Ion-pair liquid chromatography atmospheric pressure ionization mass spectrometry for the determination of quaternary ammonium herbicides

High-performance liquid chromatography coupled with atmospheric pressure ionization mass spectrometry (electrospray and atmospheric pressure chemical ionization) has been used to characterize some quaternary ammonium herbicides (quats). The separation of these compounds was carried out using ion-pair chromatography with heptafluorobutyric acid (15 mM, pH 3.3) and acetonitrile gradient elution for successful coupling to mass spectrometry. Detection limits down to 0.1-4 mu g l(-1) were obtained for spiked tap water following a preconcentration step. Good reproducibilities (day-to-day and run-to-run) were also obtained. (C) 1999 Elsevier Science B.V. All rights reserved.