Rapid determination of simazine and atrazine in water at the parts per trillion (10(12) level. Extraction by a miniaturized carbopack B trap followed by high-performance liquid chromatography.

A rapid and simple method for the determination of trace amounts of simazine and atrazine in water is described. A 250-ml volume of water is pre-concentrated by passage at a flow-rate of about 30 ml/min through a small trap containing 50 mg of graphitized carbon black (Carbopack B). After washing with 150 microliters of methanol, the two herbicides are desorbed with 700 microliters of dichloromethane-methanol (60:40, v/v). After removal, of the solvent, the extracted sample is fractionated and analysed by reversed-phase high-performance liquid chromatography with UV detection at 220 nm. A single assay can be completed within 40 min from the receipt of the water sample. Recoveries of simazine and atrazine added to 250 ml of water at the level of 50 ng/l were 97.2 and 95.8% and the limits of detection were 0.07 and 0.15 ng. respectively. At the 50 ng/l level in water, the coefficients of variation for simazine and atrazine were 3.7 and 4.0% (n = 7), respectively.