Confirmation and Quantitation of Selected Sulfonylurea, Imidazolinone, and Sulfonamide Herbicides in Surface Water Using Electrospray LC/MS

Abstract

A multianalyte method has been developed for the confirmation and quantitation of 16 selected sulfonylurea, imidazolinone, and sulfonamide herbicides in surface water. Samples are acidified, the analytes are extracted using RP-102 extraction cartridges, and the extracts are cleaned-up using an anion-exchange cartridge (SAX) stacked on top of an alumina cartridge. The final extracts are evaporated to dryness, redissolved in 10:90 or 20:80 acetonitrile/water, and analyzed using electrospray LC/MS. Confirmation criteria were defined so that identification of the analytes could be made with a reasonable degree of scientific certainty. Confirmation required that (1) LC/MS retention times of the analytes be within 1% of the retention times of the standards, (2) the molecular ion and two characteristic fragment ions per analyte be present, and (3) ion abundance ratios of the fragment ions relative to the molecular ion be within 20% of the ion ratios obtained for the standards. Each of the analytes in all of the samples used to validate this method met these confirmation criteria. Quantitation of the analytes at 0.1 and 1.0 ppb was demonstrated, with average recoveries between 70% and 114% and relative standard deviations that were less than 13%. The limit of quantitation (LOQ) for this method is 0.1 ppb (ng/mL) for all analytes. Six water types were used for the validation of this method.

Trace analysis of sulfonylurea herbicides in water by on-line continuous flow liquid membrane extraction–C18 precolumn liquid chromatography with ultraviolet absorbance detection

“…probably is because TBM hydrolyzed rapidly when Table 3 indicates that the recoveries were in the acidified [1] and the chlorine present in tap water reacts with the degraded TBM more easily [9]. In this procedure is also very stable, no significant our experiment it was observed that TBM standard difference was observed after hundreds of uses solution at low concentration is much less stable than during 2 months of experiments.…”

“…[1,4,[6][7][8][9][10] is the most commonly used one because 50 Because of the low dose used and chemical instabiliof the polarity and thermal instability of sulty, sulfonylureas are present at very low concenfonylureas. LC-mass spectrometry (MS) methods trations in environmental waters, which presents a [1,4,[7][8][9][10], which have the advantages of high challenge for their determination in recipient waters.…”

“…Due to the low level present, clean-up and enrichment before analysis are necessary and become a crucial step for the determination of sulfonylureas in environmental samples. A number of methods have been reported for the enrichment of these compounds, and solid-phase extraction (SPE) is the most widely used one [1,4,[7][8][9].…”

“…Though Carbograph 4 21 ng l when 120 ml of water samples were enriched [7] and RP-102 [4,9] were reported to be better for determination. Obviously, the detection limits are sorbents for extracting sulfonylureas from aqueous dependent on the sample matrix and volume ensamples, C sorbent was used for comparison in this 18 riched.…”

Determination of Ten Sulfonyl Urea Herbicides in Unpolished Rice by Solid-phase Extraction Cleanup and LC-Diode Array Detection

“…Therefore, liquid chromatography (LC) with photoconductivity detection 2), 3) , UV detection and diode array detection (DAD) 4)ῌ7) , and capillary electrophoresis 8), 9) have been developed. Recently, LC coupled to mass spectrometry (LC/MS) 10), 11) was also demonstrated to be suitable for SU analysis. The high polarity and chemical instability of SUs make them di$cult to extract, cleanup and determine simultaneously, and little work has been reported on the analysis of multiple SUs in food 6), 8), 9) .…”