Determination of phenoxyalkanoic acids and other herbicides at the ng/ml level in water by solid-phase extraction with poly(divinylbenzene-co-N-vinylpyrrolidone) sorbent and high-performance liquid chromatography-diode-arraydetection

A method for the determination of phenoxyalkanoic acids and other polar com pounds in environmental water samples without pH adjustment before extracti on has been developed. Recoveries were calculated from 500 ml of milliQ wat er spiked at the level of 0.5 ng/ml using solid-phase extraction (SPE) and HPLC-DAD. Different SPE materials (RP-C-18, ENV+, ENV+-C-8, SAX and Oasis H LB) were tested. After method optimization, 15 of the 16 compounds studied could be extracted with recoveries better than 70% on the most suitable cop olymeric poly (divinylbenzene-co-N-vinylpyrrolidone) material (Oasis HLB ca rtridges). (C) 2000 Elsevier Science B.V. All rights reserved.