MONITORING OF HERBICIDES IN RIVER WATER BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY AND SOLID-PHASE EXTRACTION

A gas chromatography-mass spectrometric method was developed to determ ine concentrations of herbicides in both the dissolved phases and the suspended phase of river water. The target herbicides were 2-amino-3-c hloro-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, naproanil ide, oxadiazon, pendimethalin, piperophos, pretilachlor, prometryn, si mazine, simetryn, thiobencarb and trifluralin. The herbicides in filte red river water were extracted with styrene-divinylbenzene copolymer a nd were eluted with acetone. The herbicides on suspended substances we re extracted ultrasonically with acetone. Recoveries of the herbicides on the overall performance of this method were 81.6% to 128% from fil tered river water and 80.0% to 110% from suspended substances. The min imum detectable concentrations in water and suspended substances range d from 0.01 mu g l(-1) to 0.02 mu g l(-1) and 0.05 mu g g(-1) to 0.1 m u g g(-1), respectively. This method was successfully applied to monit oring herbicides in river water.