Chlorsulfuron, detection

A multiresidue analytical method based on sohd-phase extraction enrichment combined with ce has been reported to isolate, recover, and quantitate three sulfonylurea herbicides (chlorsulfuron, chlorimuron, and metasulfuron) from soil samples (105). Optimi2ation for ce separation was achieved using an overlapping resolution map scheme. The recovery of each herbicide was >80% and the limit of detection was 10 ppb (see Soil chemistry of pesticides). 

Sulfonylureas are not directly amenable to gas chromatography (GC) because of their extremely low volatility and thermal instability. GC has been used in conjunction with diazomethane derivatization, pentafluorobenzyl bromide derivatization, and hydrolysis followed by analysis of the aryl sulfonamides. These approaches have not become widely accepted, owing to poor performance for the entire family of sulfonylureas. Capillary electrophoresis (CE) has been evaluated for water analysis and soil analysis. The low injection volumes required in CE may not yield the required sensitivity for certain applications. Enzyme immunoassay has been reported for chlorsulfuron and triasulfuron, with a limit of detection (LOD) ranging from 20 to 100 ng kg (ppt) in soil and water. 

Product-ion MS-MS mass spectra of sulfonylureas, based on a protonated molecule generated by ESI, were reported by Li et al. [53], For most compounds, only two or three prodnct ions were detected, e.g., m/z 141 and 167 for chlorsulfuron, and m/z 150 and 199 for sulfometuron methyl. The [R,N=C=0+H]" fragment is a common fragment in MS-MS. Negative-ion MS-MS mass spectra of chlorsulfuron, metsnUuron-methyl, thifensulfuron-methyl, and tribenuron-methyl were tabulated [43, 52]... 

General LC/MS Conditions for Sulfonylurea Multiresidue Analysis. We have developed general thermospray LC/MS conditions for the purpose of separating and detecting six different sulfonylurea herbicides. These conditions can be used as a guide fra- a variety of LC/MS residue applications which may require the analysis of one or more of these herbicides. Our procedure includes GLEAN (chlorsulfuron), ALLY (metsulfuron methyl), HARMONY (thiameturon) and EXPRESS cereal herbicides, CLASSIC (chlorimuron ethyl) soybean herbicide and OUST (sulfometuron-methyl) noncrop land herbicide. (Structure 1)... 

Chlorsulfuron Competitive assay amperometric detection 0.01 ngmL-1 3... 

In other studies, it was shown that pretreatment with the safeners dichlormid and naphthalic anhydride (NA) increased significantly the activity of ALS in treated corn seedlings. The in vitro inhibition of ALS by chlorsulfuron, however, was either unaltered or increased by pretreatment with the safeners. Rubin and Casida proposed that the dichlormid-induced elevation in ALS activity in vivo is sufficient to offer partial protection to corn against injury from the herbicide chlorsulfuron. In similar studies on the interactions between safeners and imidazolinone herbicides, Barrett failed to detect any measurable effects of the safeners NA, dichlormid, oxabetrinil, and flurazole on extractable ALS activity in shoots or roots of corn and sorghum seedlings. 

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