MICROWAVE-ASSISTED SOLVENT-EXTRACTION (MASE) FOR THE EFFICIENT DETERMINATION OF TRIAZINES IN SOIL SAMPLES WITH AGED RESIDUES

The use of microwave-assisted solvent extraction (MASE) as an alternat ive for conventional solvent extraction procedures for the determinati on of some triazine herbicides in soil samples has been investigated. In this study MASE method development was focused on the selection of a suitable extraction solvent prior to the instrumental analysis of un cleaned extracts with gas chromatography and nitrogen-specific detecti on. A mixture of dichloromethane-methanol (90:101 v/v) yielded recover ies ranging from 89 to 103 (spiked level 200 mu g/kg) with RSDs rangin g from 2.1 to 5.3 %. This solvent mixture is also very convenient for further procedure. The selected MASE procedure was tested by analyzing freshly spiked soil samples and samples with aged residues of atrazin e, desethylatrazine, desisopropylatrazine and simazine. The results we re compared with those obtained by a conventional liquid extraction me thod. The comparative study indicated that MASE yields recoveries at l east as good as those obtained by the conventional method. Moreover, t he MASE procedure provides low solvent consumption in combination with a high sample throughput.