Pesticides coumaphos

The enone (130), the pesticide Coumaphos, undergoes regioselective dimerization on irradiation at wavelengths > 313 nm. The product was identified as the dimer (131). Irradiation of the furocoumarin, Imperatorin (132), in methanol affords a low yield of the (2t2)-dimer (133). This product is accompanied by the dealkylated compound (134) and the rearrangement product (135). This last compound is formed by a photo-Claisen rearrangement. The influence of solvent was studied and the dimer was obtained only in methanol. The other two products were formed in a variety of polar and non polar solvents. In any solvent the dealkylated compound (135. was the main product. ... 

In an approach to utilize enzymes to degrade pesticides recombinant organo-phosphate hydrolase (OPH) was anchored to the surface of E.coli cells and packed in a bioreactor [7]. A similar approach used E.coli cells with OPH on the surface, immobilized on glass beads [7], silica beads [8] or nylon [9]. In 2005 a group reported the immobilization of the pesticide degrading enzyme OPH on a cellulose matrix. The enzyme was attached to the matrix via a cellulose binding domain [10]. When packed in a column bioreactor the immobilized OPH was able to degrade a 0.2 mM solution of the pesticide coumaphos rapidly and without loss of activity over 2 months [11]. Another possibility to use enzymes in a solid form to catalyze... 

Laboratory-scale smdies in degradation of pesticides are very important, since they allow the simulation of the behavior of pesticides in conditions that can be applied on field-scale. Mulbry et al., have developed a biofilter capable of handling about 15,000 dip-liter batches of dip waste containing the organophosphate pesticide, coumaphos. This biofllter was able to reduce the concentration of couma-phos from 2000 to 10 ppm in approximately 14 days at 25-29 °C, demonstrating the importance of the field-scale smdies (Mulbry et al. 1998). 

Organophosphorus pesticides, e.g. coumaphos, menazon, maretin, dursban 200 °C, 45 min Induced fluorescence or amplification of natural fluorescence, detection limits 1-80 ng. [21]... 

Organophosphorus pesticides, e.g. coumaphos, menazon, maretin, dursban... 

Although the inhibition-based biosensors are sensitive, they are poor in selectivity and are rather slow and tedious since the analysis involves multiple steps of reaction such as measuring initial enzyme activity, incubation with inhibitor, measurement of residual activity, and regeneration and washing. Biosensors based on direct pesticide hydrolysis are more straightforward. The OPH hydrolyzes ester in a number of organophospho-rus pesticides (OPPs) and insecticides (e.g. paraoxon, parathion, coumaphos, diazinon) and chemical warfare agents (e.g. sarin) [53], For example, OP parathion hydrolyzes by the OPH to form p-nitrophenol, which can be measured by anodic oxidation. Rainina... 

Brown RL, Farmer CN, Millar RG. 1987. Optimization of sweep codistillation apparatus for determination of coumaphos and other organophosphorus pesticide residues in animal fat. J Assoc Off Anal Chem 70(3) 442-445. 

Coumaphos, like other organophosphates, was originally developed as a pesticide for treatment of external parasites of animals, but later came to be used... 

Most of the older methods of fluorimetric analysis of pesticides involved hydrolysis to form fluorescent anions. Co-ral (coumaphos) [147] was hydrolyzed in alkali to the hydroxybenzopyran, which was subsequently determined by means of its fluorescence. Guthion (azinphosmethyl) was hydrolyzed to anthranilic acid for fluorimetric analysis [148,149]. A method was developed [150] for Maretin (N-hydroxynaphthalimide diethyl phosphate) in fat and meat which involved hydrolysis in 0.5 M methanolic sodium hydroxide followed by determination of the fluorescence of the liberated naphthalimide moiety. Carbaryl (1-naphthyl N-methylcarbamate) and its metabolites have been determined by a number of workers using base hydrolysis and the fluorescence of the resulting naphtholate anion [151-153]. Nanogram quantities of the naphtholate anion could be detected. Zectran (4-dimethylamino-3,5-xylyl N-methylcarbamate) has been determined by the fluorescence of its hydrolysis product [154]. The fluorescence behaviour of other carbamate insecticides in neutral and basic media has been reported [155]. Gibberellin spray used on cherries has been determined fluorimetrically after treatment with strong acid [156]. Benomyl (methyl N-[l-(butylcarbamoyl)-2-benzimidazolyl]carbamate) has been analyzed by fluorimetry after hydrolysis to 2-aminobenzimidazole [157]. 

Coumaphos is of interest because it is the most effective pesticide against varroa mites and small hive beetles in beehives and is an ingredient of insecticide strips hung in the hives to kill the mites.9 There is some concern regarding this use because of coumaphos detected in honey. The U.S. EPA has granted extensions for the use of coumaphos in beehives, including one to run from February 2, 2002, to February 1, 2003. 

Bayer s checkmite (coumaphos) has been given a specific exemption by the EPA to the California Department of Pesticide Regulation for use on beehives to control varroa mites, Chemical Business NewsBase Agricultural Chemical News, May 15, 2001, p. 1. 

U.S. Environmental Protection Agency, Pesticide Fact Sheet Number207 Coumaphos. Office of Pesticides and Toxic Substances, Washington, DC, pp. 5-19, 1989. 

Another organophosphorus insecticide, Bayrusil (XIII) becomes fluorescent upon heat treatment but the fluorescence yield is less than with coumaphos (around 0.01 yg/spot) (4 4). This pesticide has also been analysed in foodstuffs at the 0.02 ppm level (46 ). ... 

Organophosphate hydrolysis is frequently observed as the initial reaction for pesticides having organophosphate bonds, such as methyl parathion, chlorpyrifos (9) (eq. 13), diazinon, and coumaphos (19). Several genera of organophosphate-hydrolyzing bacteria have been identified, including... 

Quantitative analysis of the organophosphorous pesticides acephate, azinphos, chlorpyrifos, coumaphos, diazinon, isazofos, malathion, methamidophos, parathion, pirimiphos, and their O.O-dimethyl analogues in human urine using LC-MS-MS [143]. 

A mystery illness that affected 17 casino workers following fumigation of the premises with a pesticide mixture that contained the carbamate propoxur (1.52), the organophosphate coumaphos (4.13), 1,1,1-trichloro-ethane (2.49), methylene chloride (1.25), xylene (3.15), and acetone... 

The OPPs with an aromatic ring (e.g., azinphos-methyl, azinphos-ethyl, coumaphos, diazinon, fenitrothion, fenthion, parathion, paraoxon, tetrachlorvinphos, trichloronate) can be determined with UV/DAD because they contain good chromophores. Problems are encountered with pesticides such as, dimethoate, disulfoton, malathion, or trichlorfon, which have no chromophores. The wavelength data for analyzing OPPs using LC-UV/DAD are given in Table 23.13. 

Coumarin derivative pesticides, those based on coumarin (91-64-5), including warfarin, coumaphos, and coumafuril. 

Mata-Sandoval et al. [32] compared the ability of the rhamnolipid mixture to solubilize the pesticides, trifluralin, coumaphos and atrazine, with the synthetic surfactant Triton X-100. The synthetic surfactant was able to solubihze approximately twice as much of all pesticides as the rhamnolipid. The biosurfactant seems to bind trifluralin tightly in the micelle and releases the pesticide slowly to the aqueous phase, which could have implications for microbial uptake. This approach utilizing micellar solubilization capacities and aqueous-miceUe solubilization rate coefficients and micellar-aqueous transfer rate coefficients could be useful for future studies on microbial uptake. Addition of rhamnohpid in the presence of cadmium enabled biodegradation of the hydrocarbon naphthalene to occur as if no cadmium was present [33]. 

Seventeen organophosphate pesticides (e.g., famphur and famphur oxon, para-oxon, fenthoxon, ronnel, 3-chloro-4-methyl-7-hydroxycoumarin, stitofos, parathion, coumaphos) were extracted from beef tissues and baseline resolved on a C g colunm (photodiode array detector, A = 190-350 nm). A complex 34-min 55/45 - 70/30 acetonitrile/water gradient was used [957]. Excellent peak shapes were obtained. A... 

Organophosphorus hydrolase (OPH, EC 3.1.8.1) is a homodimer with a binuclear metal center. OPH has broad substrate specificity and can hydrolyze organophosphate pesticides such as methyl paradiion, ediyl parathion, paraoxon, chlorpyrifos, coumaphos, cyanophos and diazinoa Table I 9,12-14). The enzymatic hydrolysis rates are 40 - 2450 times faster than chemical hydrolysis at pH 7.0 and the enzyme is reported to be stable at ten ratures of up to 4S-S0°C (3). However, hydrolysis rates varied from very fast for phosphotriesters and phosphothiolester pesticides (P-0 bond) such as paraoxon (ken > 3800s ) and coumaphos (kcat = 800s ) to limited hydrolysis for Diazinon (kcat == 176 s ) and fensulfothion (l a, = 67 s ) (14). 

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