Comparison of the performance of graphitized carbon black and poly(styrene-divinylbenzene) cartridges for the determination of pesticides and industrial phosphates in environmental waters

The determination of polar and nonpolar organophosphorus compounds, triazin es and their metabolites, molinate and chlorothalonil in 1 1 water samples was investigated using off-line solid-phase extraction followed by gas chro matography with nitrogen-phosphorus and flame photometric detection. The et hylvinylbenzene-divinylbenzene copolymer (LiChrolut EN) and the commercial graphitized carbon black (GCB) of Envi-Carb were tested as solid-phase sorb ents. The matrix effect was studied by extracting the compounds spiked in w ater samples of different types (Milli-Q, tap, salted tap water, river and sea water). The polymeric sorbent LiChrolut EN allowed the determination at low ng/l of all 40 compounds tested, except the very polar atrazine-deseth yl-deisopropyl (DDA). Recoveries of compounds from the Envi-Carb sorbent ar e comparable to those obtained for LiChrolut EN with the exception of chlor othalonil and the more hydrophobic organophosphorus compounds (coumaphos, l eptophos), which were strongly sorbed in the Envi-Carb cartridges. Envi-Car b, however, enabled the determination of DDA with a limit of detection of 1 4 ng/l. (C) 1999 Elsevier Science B.V. All rights reserved.