Metolachlor sulfonic acid

Limits of detection for each of the six soil metabolites in surface water and ground-water were determined by using an estimate of variability for the 0.25 pgL fortifications from samples analyzed along with hundreds of surface water and groundwater sets during the years 1999-2001. During these years, the estimated LODs were below 0.1 ug for acetochlor sulfonic acid, acetochlor oxanilic acid, alachlor oxanilic acid, metolachlor sulfonic acid, and metolachlor oxanilic acid and about 0.1 igL for alachlor sulfonic acid. If the actual concentration of an analyte is at this detection limit or greater, there is at least a 95% chance of detection. 

LOQs for each of the six soil metabolites in surface water and groundwaters were determined using analytical results (not corrected for background) of samples fortified at the lowest fortification level, 0.25 igL during the analysis in years 1999-2001. The calculated LOQs for acetochlor oxanilic acid, metolachlor sulfonic acid and metolachlor oxanilic acid are below 0.25 ig L. The calculated LOQs for acetochlor sulfonic acid, alachlor sulfonic acid, and alachlor oxanilic acid are below 0.10 igL. If the true concentration of an analyte is at the LQQ or greater, the standard error of individual measured concentration values relative to the true concentration is at most 10%. 

Sulfonic acids are produced as metabolites of alachlor and meto-lachlor, and the metabolite from metolachlor has been synthesized for FAB-MS comparison with the compound isolated from soil (Aga et al. 1996). 

Chloroacetanilide herbicide Metolachlor stereoisomers and two metabolites (ethane sulfonic acid, oxaniUc acid) in ca. 24.5 min... 

Aga, D.S. Thurman, E.M. Formation and transport of the sulfonic acid metabolites of alachlor and metolachlor in soil. Environ. Scl Technol 2001,35,2445-2460. 

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