Monitoring of herbicides in river water by gas chromatography-mass spectrometry and solid-phase extraction

Abstract

A gas chromatography-mass spectrometric method was developed to determine concentrations of herbicides in both the dissolved phases and the suspended phase of river water. The target herbicides were 2-amino-3-chloro-1,4-naphthoquinone, alachlor, benfluralin, bifenox, bromobutide, the debromo form of bromobutide, butachlor, butamifos, chlomethoxyfen, chlornitrofen, chlorpropham, dimepiperate, dimethametryn, dithiopyr, esprocarb, MCPA-ethyl, MCPA-thioethyl, mefenacet, molinate, naproanilide, oxadiazon, pendimethalin, piperophos, pretilachlor, prometryn, simetryn, thiobencard and trifluralin. The herbicides in filtered river water were extracted with styrene-divinylbenzene copolymer and were eluted with acetone. The herbicides on suspended substances were extracted ultrasonically with acetone. Recoveries of the herbicides on the overall performance of this method were 81.6% to 128% from filtered river water and 80.0% to 110% from suspended substances. The minimum detectable concentrations in water and suspended substances ranged from 0.01 μg l −1 to 0.02 μ g l −1 and 0.05 μ g −1 to 0.1 μg g −1, respectively. This method was successfully applied to monitoring herbicides in river water.