|Berglof, Tomas - SWEDISH UNIV UPPSALA SW|
|Kylin, Henrik - SWEDISH UNIV UPPSALA SW|
Submitted to: International Association of Environmental and Analytical Chemistry
Publication Type: Abstract Only
Publication Acceptance Date: April 4, 1997
Publication Date: N/A
Technical Abstract: Sulfonylurea herbicides are usually extracted from soils with batch liquid techniques. The objective of this study was to develop a general supercritical fluid extraction (SFE) procedure for sulfonylurea herbicides in soils. The procedure was optimized for metsulfuron methyl, and the parameters investigated included: SF-CO2 density, extraction time, and methanol modifier addition. Quantitative extraction could only be performe at high densities (i.e. 0.9 g/mL) and with 2 percent (w/w) modifier addition. 14C-labeled metsulfuron methyl, sulfometuron methyl and nicosulfuron were extracted from sandy loam, silt loam, and clay loam soils spiked at two levels (0.4 and 4 ug/g) of herbicide. Under the conditions used, good recoveries of metsulfuron methyl and sulfometuron methyl (75-89 percent) were obtained. However, nicosulfuron was difficult to extract (1-4 percent). The results show that an optimized method cannot always be directly applied to similar compounds without further method development.