Monitoring of priority pesticides and other organic pollutants in river water from Portugal by gas chromatography-mass spectrometry and liquid chromatography-atmospheric pressure chemical ionization mass spectrometry

Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-atmo spheric pressure chemical ionization mass spectrometry (LC-APCI-MS) were op timized and applied for the trace-level determination of 42 priority pestic ides and 33 priority organic pollutants from European Union Directive EC 76 /464. First, off-line solid-phase extraction of 200 mi of river water using an OASIS solid-phase extraction cartridge, followed by GC-MS was used. Nex t, selected samples that were positive to GC-MS were analyzed by LC-APCI-MS in order to detect further polar byproducts or to improve the determinatio n of previously detected polar analytes. The transformation products of tri azine pesticides like deethylatrazine (DEA) and deisopropylatrazine (DIA) a nd compounds such as diuron and several chlorophenols were positively ident ified by LC-APCI-MS. The present methodology has also been used far searchi ng for new analytes not included in the EC 76/464 List, like Irgarol, DEA a nd DIA. In addition it was applied to target pollutants in 43 river water s amples from Portugal during a pilot survey from April to July 1999. Atrazin e followed by simazine and 2,4,6-trichlorophenol were the most ubiquitous c ompounds detected in this area. The levels detected of the different compou nds were in the range of: 0.01-2.73 mu g/l, 0.05-0.74 mu g/l, 0.02-1.65 mu g/l, 0.02-5.43 mu g/l, 0.01-0.40 mu g/l, 0.01-0.26 mu g/l, 0.02-0.61 mu g/l , 0.01-3.90 mu g/l, 0.01-1.24 mu g/l, 0.02-2.3 mu g/l, 0.01-0.13 mu g/l and 0.01-0.5 mu g/l for atrazine, simazine, terbuthylazine, alachlor, metolach lor, Irgarol, propanil; tributhylphosphate, diuron, 2,4,6-trichlorophenol, deisopropylatrazine and deethylatrazine, respectively. (C) 2000 Elsevier Sc ience B.V. All rights reserved.