Pesticide residues carbamates

Yang, G. and S. Kang. 2008. SPR-based antibody-antigen interaction for real time analysis of carbamate pesticide residues. Food Sci. Biotechnol. 17 15-19. 

The most common analytical technique to analyze carbamate pesticide residues in fruits,... 

Yang, R. Z, Wang, J. H., Wang, M. 1., Zhang, R., Lu, X. Y., and Liu, W. H. 2011. Dispersive solid-phase extraction cleanup combined with accelerated solvent extraction for the determination of carbamate pesticide residues in radix glycyrrhizae samples by UPLC-MS-MS. J. Chromatogr. Sci. 49 702-708. 

Ballesteros, E., Carbamate pesticide residues in food, in Nollet, L.M.L. (Ed.), Handbook of Food Analysis, 2nd ed., Marcel Dekker, New York, 2004, Chap. 30. 

SFE. SFE has been established as the extraction method of choice for solid samples. The usefulness of SFE for soil samples has been demonstrated for carbamate,organophosphorus and organochlorine pesticides. However, SFE is more effective in extracting nonpolar than polar residues. In order to obtain a greater extraction efficiency for the polar residues of imidacloprid, the addition of 20% methanol as modifier is required. Extraction at 276 bar and 80 °C with a solvent consisting of supercritical carbon dioxide modified with methanol (5%) for 40 min gives a recovery of 97% (RSD = 3.6%, n = 10). It is possible to use process-scale SFE to decontaminate pesticide residues from dust waste. ... 

E.B. Tribaldo, Residue analysis of carbamate pesticides in water, in Food Science Technology, Marcel Dekker, New York, pp. 537-570 (2000). 

Organophosphate and carbamate pesticides are potent inhibitors of the enzyme cholinesterase. The inhibition of cholinesterase activity by the pesticide leads to the formation of stable covalent intermediates such as phosphoryl-enzyme complexes, which makes the hydrolysis of the substrate very slow. Both organophosphorus and carbamate pesticides can react with AChE in the same manner because the acetylation of the serine residue at the catalytic center is analogous to phosphorylation and carbamylation. Carbamated enzyme can restore its catalytic activity more rapidly than phosphorylated enzyme [17,42], Kok and Hasirci [43] reported that the total anti-cholinesterase activity of binary pesticide mixtures was lower than the sum of the individual inhibition values. 

Chemical degradation has been investigated by Shlh and Dal Porto Q) and by Lande ( ) under EPA auspices as an alternative approach (to landfill disposal) for the removal of pesticide residues. Among candidate reactions for the safe detoxification of pesticides, only alkaline hydrolysis was recommended. Several organophosphates and carbamates were identified as amenable to a degradation procedure using strong base/aqueous alcohol. The... 

Within this area of process development one of the first aims was to evaluate the solubility and extractability of selected representative carbamate pesticides, whose residual concentration should be as low as possible. Solubility data were obtained from experimental investigations of the related pesticides in SC - CO2 from inert matrices (sea sand) first, and later on this experience was applied for the real matrix of rice. 

The use of pesticides in agriculture has obvious advantages, such as an increase in the quantity and quality of food crops. Nevertheless, pesticides are toxic substances, and their residues can pose a risk to man and environment. Therefore, pesticide residues in food are regulated at the international and national levels according to the toxicity of the compound and the human intake of a particular crop. The acute oral toxicity for rats and the maximum residue levels (MRLs) of carbamate and urea pesticides are listed in Tables 1 and 2. 

The carbamate pesticides can also be determined by normal-phase chromatography on different columns. Silica (113-116), amine (51), and cyanopropyl (112) columns have been used for the determination of carbamate residues. These columns were used with different solvent systems, with isopropanol-heptane being the mobile phase producing generally better results and methylene chloride-heptane the preferred solvent system when nonpolar carbamates were present in the sample. Another mobile phase used was iso-octane-dioxane (113). Although normal-phase mode was for the most part satisfactory, reversed-phase mode gave generally superior results. 

BGL Schlagbauer, AWJ Schlagbauer. The metabolism of carbamate pesticides—a literature analysis. Residue Reviews 42 1-90, 1972. 

RJ Argauer. Determination of residues of band and other carbamate pesticides after hydrolysis and chloroacetylation. J Agric Food Chem 17 888-892, 1969. 

High-performance LC methods for pesticide residue analysis were first developed for nonvolatile or thermally labile compounds, such as carbamate insecticides. Because HPLC offers a simpler and/or faster approach to analysis for a wide range of other compounds, it is becoming more and more widely accepted, and its applications are steadily increasing in number. Although HPLC has been used in the analysis of OCPs and OPPs, the literature on its application in food is scarce. The methods reported have been summarized in Table 4. 

The use of NBD-Cl for the fluorescence analysis of alkylamine-generating pesticides has been investigated [173]. A two-phase reaction system is employed for the hydrolysis and labeling of N-methyl- and N,N-dimethyl-carbamate pesticides. The residue is hydrolyzed in 0.1 M sodium carbonate and the liberated amine is treated with NBD-Cl in an organic phase (IBMK, isobutyl methyl ketone) above the aqueous layer. An aliquot portion of the organic layer is used for chromatography. The reactions involved are shown in Fig. 4.65. 

OP compounds and carbamate are widely used as insecticides, pesticides, and warfare agents [20,21], Detection of pesticides is usually carried out by multiresidue methods (MRMs) of analysis, which are able to detect simultaneously more than one residue and have been developed mainly based on chromatographic techniques. Two groups of MRMs are used (i) multiclass MRMs that involve coverage of residues of various classes of pesticides, and (ii) selective MRMs, which concern multiple residues of chemically related pesticides (e.g., IV-methyl carbamate pesticides (NMCs), carboxylic acids, phenols, etc.). As foods are usually complex matrices all of the pre-analytical steps (matrix modification, extraction, and clean-up) are often necessary. 

The electrolytic conductivity detector for gas chromatography was developed by Coulson (15, 16, 17), who described modes of operation for the detection of chlorine, sulfur, or nitrogen, but did not establish the reliability of the detector for pesticide residue analysis or the minimum detectability for each molecular species. Cassil et al. (11) described the use of the detector for determining residues of carbamate pesticides and compared its response with that of the microcoulometric detector, as mentioned earlier, finding them equal in response and selectivity and usable over a range of 3 to 200 ng of nitrogen. An improved pyrolysis tube was described, and nickel wire or turnings was used as the catalyst... 

Pesticide residues Acetochlor Alachlor Atrazine Carbendazin/Benomyl Cyclodienes, 2,4-D DDE Diuron Glyphosate Metolachlor Organophosphate/Carbamate Pyrethroids Spynosyn Surfactants Alkyl ethoxylate (AE) Alkylphenol ethoxylate (APE) Linear alkylbenzene sulfonate (LAS) Estrogens 17-B-Estradiol (E2) ... 

Sagratini, G., Manes, J., Giardina, D., Damiani, P., and Pico, Y. (2007). Analysis of carbamate and phenylurea pesticide residues in fruit juices by solid-phase microextraction and hquid chromatography-mass spectrometry, J. Chromatogr. A, 1147,135-143. 

LLE is a widely used technique among the official US-EPA methods for the preconcentration of pesticides in liquid samples. Nonpolar solvents for the LLE of pesticides include w-hexane, benzene, and ethyl acetate. Water-miscible solvents for this purpose include dichloromethane, methanol, acetonitrile, acetone, and water, which have been employed for the extraction of residues from high-moisture commodities. Mixed solvents have often been used to finely adjust the solvent strength. Thus, various carbamate pesticides were extracted from aqueous environmental samples with chloroform and determined by HPLC with a mean recovery of 71 Also, a method based on the extraction by sonication of solid samples placed in small columns with a low volume of ethyl acetate was developed for the extraction of thiocarbamates and other herbicides from soil with recoveries between 89 and 109%. ... 

Padilla, S., and M. J. Hooper. 1992. Cholinesterase measurements in tissues from carbamate-treated animals. Cautions and recommendations. Proceedings of the U.S. EPA Workshop on Cholinesterase Methodologies, pp. 63-81. Washington, D.C. Office of Pesticide Residue Programs, U.S. Environmental Protection Agency. 

Aldicarb nitrile (12), a residual degradation product of the carbamate pesticide Aldicarb, can be analysed by GC using a short column and MS detection, with a detection limit of 0.15 ng. The short column is required to avoid thermal degradation of Aldicarb to 12 that could distort the analysis . 

The analysis of pesticide residues and metabolites in foods can be a difficult problem because of the complexity of the matrix and the trace levels at which the analytes must be detected. Capillary SFC has been shown to be a very effective technique for the analysis of trace levels of pesticides, especially when a selective detector such as the NPD is used (18). Figure 7 shows an example of the determination of selective carbamate pesticides in parsley. The sample was prepared by extraction of 1 gram of... 

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