Chloroacetanilide soil metabolites

The method for chloroacetanilide soil metabolites in water determines concentrations of ethanesulfonic acid (ESA) and oxanilic acid (OXA) metabolites of alachlor, acetochlor, and metolachlor in surface water and groundwater samples by direct aqueous injection LC/MS/MS. After injection, compounds are separated by reversed-phase HPLC and introduced into the mass spectrometer with a TurboIonSpray atmospheric pressure ionization (API) interface. Using direct aqueous injection without prior SPE and/or concentration minimizes losses and greatly simplifies the analytical procedure. Standard addition experiments can be used to check for matrix effects. With multiple-reaction monitoring in the negative electrospray ionization mode, LC/MS/MS provides superior specificity and sensitivity compared with conventional liquid chromatography/mass spectrometry (LC/MS) or liquid chromatography/ultraviolet detection (LC/UV), and the need for a confirmatory method is eliminated. In summary,... 

Biological. In an anaerobic medium, the bacteria of the Paracoccus sp. converted 4-chloroaniline to l,3-bis(/t-chlorophenyl)triazene and 4-chloroacetanilide with product yields of 80 and 5%, respectively (Minard et al., 1977). In a field experiment, [ C]4-chloroaniline was applied to a soil at a depth of 10 cm. After 20 wk, 32.4% of the applied amount was recovered in soil. Metabolites identified include 4-chloroformanilide, 4-chloroacetanilide, 4-chloronitrobenzene, 4-chloronitrosobenzene, 4,4 -dichloroazoxybenzene, and 4,4 -dichloroazobenzene (Freitag et al, 1984). 

Rheineck, B. and J. Postle. Chloroacetanilide Herbicide Metabolites in Wisconsin Groundwater Final Report. 9 pgs. Wisconsin Department of Agriculture, Trade and Consumer Protection. 2001. www.soils.wisc.edu/extension/FAPM/proceedings01 (Accessed June, 2002). 

Environmental monitoring of chloroacetanilides requires methods that have the capability to distinguish between complex arrays of related residues. The two example methods detailed here for water monitoring meet this requirement, but the method for metabolites requires sophisticated mass spectral equipment for the detection of directly injected water samples. In the near term, some laboratories may need to modify this method by incorporation of an extraction/concentration step, such as SPE, that would allow for concentration of the sample, so that a less sensitive and, correspondingly, less expensive, mass spectral detector can be used. However, laboratories may want to consider purchasing a sensitive instrument rather than spending time on additional wet chemistry procedures. In the future, sensitive instrumentation may be less expensive and available to all laboratories. Work is under way to expand the existing multi-residue methods to include determination of additional chloroacetanilides and their metabolites in both water and soil samples. 

There are fewer applications of PEE to the extraction of herbicides in soils,being mainly used until now for PAH and PCB extractions. Guzella and Pozzoni performed one of the first successful studies with PEE, by comparing it with Soxhlet procedures on triazine and chloroacetanilide extractions from agricultural soils.A PEE method was developed to extract metribuzin and three metabolites (deaminometribuzin, deaminodiketometribuzin, and diketometribuzin) with methanol-water (75 25) at 60°C. Recoveries were about 75% with detection limits of 1 ng/g, except for diketometribuzin with only 50% of recovery and detection limit higher than 10 ng/g. ... 

In order to determine ureas and metabolites of triazines and ureas in agricultural soils, reverse-phase liquid chromatography was used with atmospheric pressure chemical ionization/mass spectrometry (APCI/MS), in positive mode. Gas chromatography/ion trap mass spectrometry was used in MS/MS mode to analyze the parent compounds of the triazines and chloroacetanilides. Method performance was much better in GC-MS/MS than in LC-MS, and acetochlor LOQ was dramatically improved by using GC-MS/MS, this herbicide being very poorly ionized into the APCI interface. 

Dagnac, T., Jeannot, R., Mouvet, C., and Baran, N., Determination of chloroacetanilide metabolites in water and soils by LC/ESI-MS. p. 103 in 2nd MGPR international Symposium of pesticides in food and the environment, Valencia (Spain), 9-12 may 2001. 

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