Simultaneous analysis of triasulfuron, metsulfuron-methyl and chlorsulfuron in water and alkaline soils by high-performance liquid chromatography

A method capable of simultaneously detecting residues of three sulfonylurea herbicides at mu g/l and mu g/kg level in water and alkaline soils has bee n described. The method is based on solid phase extraction and HPLC with UV detection. In alkaline soils especially those containing low organic carbo n it was possible to extract the herbicides with de-ionised water and no cl ean up step was needed. Soil samples spiked with technical grade triasulfur on, metsulfuron-methyl and chlorsulfuron were extracted twice by shaking wi th de-ionised water for one hour and centrifuging at 10000 rpm for 15 minut es. Supernatants filtered through glass micro-fibre filters were passed thr ough C-18 cartridges previously pre-conditioned with methanol and de-ionise d water at a flow rate of < 20 ml/min. Residues of the herbicides retained on the cartridge were eluted with acidified methanol. The eluate was analys ed by HPLC. A C-18 column was used with a mobile phase of methanol/water (4 0 + 60, VN for for the herbicide residues were 1.0 mu g/l and 3 mu g/l in w ater and soil, respectively. The average recoveries for water samples range d from 73 - 94%, while for soil samples recoveries were 77 - 97% for the th ree compounds studied.