Determination of the pesticide naptalam and its degradation products by positive and negative ion mass spectrometry

N-1-Naphthylphtalamic acid (naptalam) and its degradation products, 1-napht hylamine and N-(1-naphthyl) phthalimide were simultaneously determined in r iver water by two independent mass spectrometric (MS) methods. These were n egative ion MS (NIMS) and programmable temperature vaporizer gas chromatogr aphy mass spectrometry (PTV-GC MS) with electron impact ionization (positiv e ions). Prior to the NIMS analysis, the samples were preconcentrated by so lid phase extraction (SPE) of C-18 membrane discs. The PTV-GC MS studies we re performed without any preconcentration procedure. Selected ion monitorin g (SIM) and internal standardization with naphthalene were applied in both methods. The limits of determination (LOD) of NIMS studies were 230, 270 an d 260 ng L-1 for naptalam, 1-naphthylamine and N(1-naphthyl) phthalimide, r espectively, with relative standard deviation (RSD) < 1% (n = 5) and of PTV -GC MS 17, 11 and 15 ng L-1 (RSD < 0.7%, n = 5). The LOD, linearity, RSD an d time required for these methods are far better than for HPLC analyses.