OPTIMIZATION OF THE LIQUID-CHROMATOGRAPHIC SEPARATION OF PIRIMICARB AND ITS METABOLITES V-VII - APPLICATION TO A SOIL SAMPLE USED AS A CANDIDATE REFERENCE MATERIAL

The simultaneous separation of the N-dimethylcarbamate pirimicarb and its metabolites V-VII was carried out by liquid chromatography (LC) us ing diode array detection (DAD). Two columns, a 250 x 4.6 mm i.d. colu mn packed with 5-mu m particles with a cyanopropyl modified silica sta tionary phase and a 150 x 4.6 mm i.d. column packed with 3-mu m partic les with a base deactivated C-8 modified silica stationary phase, were compared. The addition of a buffer in the eluent, for both columns, w as needed to improve the peak shape of metabolite V and the resolution of the metabolites V-VII and consequently the pH dependence of the re tention time was tested. Additionally chromatograms of two soil sample s of different origin, spiked at a concentration level of 1 mu g g(-1) for pirimicarb, analysed by LC-DAD, gas chromatography (GC) with nitr ogen phosphorus detection and GC-mass spectrometry are shown. Detectio n limits and reproducibility data of pirimicarb in a candidate referen ce sample using LC-DAD and a cyanopropyl column are reported.