Phenylureas metabolites

Continued study of the phenylurea herbicides in soils is needed. First of all, we must determine whether soil microorganisms are able to demethylate these phenylurea herbicides and secondly, whether enzymes may be present in plant roots which contribute to the phenylurea metabolites found in soils. 

This paper deseribes a rapid and versatile on-line-SPE LC-MS/MS method developed for the determination of various pestieides and tlieir metabolites in water. 28 pestieides, ineluding various triazines, phenylureas, organophosphorous eompounds and other speeies, were seleeted for systematie investigations. 

The major metabolite of buprofezin in plants is its p-hydroxy metabolite (p-OH-buprofezin) and that in soil is l-isopropyl-3-phenylurea (BF12). The target analytes are considered to be buprofezin and p-OH-buprofezin in plant materials, buprofezin and BF12 in soils and buprofezin in water samples. 

A Cis disk has been used to remove chlorotriazine, atrazine, metabolites, organophosphorus compounds, phenylurea, and carbamate pesticides from seawater prior to analysis by HPLC [392],... 

CASRN 1982-47-4 molecular formula C15H15CIN2O2 FW 290.75 Soil Hartley and Kidd (1987) reported 4-(4-chlorophenoxy)aniline as a soil metabolite. Chloroxuron was degraded by microorganisms in humus soil and a sandy loam forming -(4-chlorophenoxy)phenyl-A-methylurea, W-(4-chlorophenoxy)phenylurea, and 4-(4-chlorophenoxy)-aniline, and two minor unidentified compounds (Geissbiihler et al., 1963). Residual activity in soil is limited to approximately 4 months (Hartley and Kidd, 1987). 

Corcia, A. D., Costantino, A., Crescenzi, C., and Samperi, R., Quantihcation of phenylurea herbicides and their free and humic acid-associated metabolites in natural waters, J. Chromatogr. A, 852, 465-474, 1999. 

FIGURE 25.20 SIM LC-ES/MS of an extract of 4 1 drinking water spiked with PUHs and their metabolites. Individual spike level 2 ng/1. MS data acquisition was performed by using 8 retention windows. Acronyms AA, aromatic amine M, metabolite PhU, partial or total dealkylated phenylurea herbicid IS, internal standard (monuron). (From Di Corcia, A., Costantino, A., Crescenzi, C., and Samperi, R., J. Chromatogr., 852, 465, 1999.)... 

Chlorinated anilines are common metabolites of the microbial degradation of various phenylurea, acylanilide and phenylcarbamates herbicides (Figure 13). Basicity and oxidabiUty are the features of tiiese compoxmds. They can react with oxygen and ozone present in air, with soil components [235-237], with lignin of plants [238], and with the microbial enzymatic systems. 

Phenoxy acids (2,4-dichlorophenoxy acetic acid, MCPA, and 2,4,5-trichlorophenoxy acetic acid) and similar acid herbicides (benzaton, dicamba, dichlorprop, and mecoprop) sulfonurea herbicides (chlorsulforon, metsulforon methyl, tribenuron methyl, and thifensulfuron methyl) triazine herbicides (methoxy-s-triazines, chloro-s-triazines, alkylthio-s-triazines) phenylurea herbicides (fenuron, monolinuron, and diuron), metabolites of the fungicide thiophanate-methyl (carbenazim and 2-aminobenzimidazole)... 

Soil. A fungus and two Pseudomonas spp. isolated fi om soil degraded siduron to form the major metabolites l-(4-hydroxy-2-methylcyclohexyl)-3-(/7-hydroxyphenyl)urea, l-(4-hydroxy-2-methyIcyclohexyl)-3 -phenylurea and 1 -(4-hydroxyphenyl)-3 -(2-methycyclo-hexyl)urea (Belasco and Langsdorf, 1969). 

Supercritical fluid extraction (SEE) allows the analysis not only of the water samples but more complicated systems as well, e.g., of pesticides in soil samples (41a) and triazines and phenylureas in sediment (41b). Heptachlor and its metabolites, dieldrin, endrin (41c) were extracted from animal tissues by this method using only CO2 or organic solvent containing COj. Twelve OP and OC insecticides were extracted from quite different soil samples, i.e., sand, clay, etc., by SEE either with CO2 or with 3% methanol containing CO2 gas (41d) (Table 1). 

Carbendazim (F), triazines, carbamates, phenylureas, and their metabolites (H) 1.33 mL SW, GW Online Cis silica CH3CN/H2O 0.01% formic acid [75]... 

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