Organophosphorus pesticides detecting

On a different setup, Du et al. [31] cast sol-gel silica/gold nanoparticle nanocomposite films on a glassy carbon electrode, which was then impregnated with an acetylcholinesterase (AChE) enzyme (Figure 46.10). The construct was used as a biosensor for organophosphorus pesticide detection. In this system, gold nanoparticles not only offered a biocompatible microenvironment to retain the activity of adsorbed enzyme molecules but also acted as a wire to enhance the direct electron transfer rate between the enzyme active centers and the electrode surface, which otherwise would be blocked by the thick protein shell of the enzyme chemical structure. 

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]... 

Methyl parathion was determined in dog and human serum using a benzene extraction procedure followed by GC/FID detection (Braeckman et al. 1980, 1983 DePotter et al. 1978). An alkali flame FID (nitrogen-phosphorus) detector increased the specificity of FID for the organophosphorus pesticides. The detection limit was in the low ppb (pg/L). In a comparison of rat blood and brain tissue samples analyzed by both GC/FPD and GC/FID, Gabica et al. (1971) found that GC/FPD provided better specificity. The minimum detectable level for both techniques was 3.0 ppb, but GC/FPD was more selective. The EPA-recommended method for analysis of low levels (<0.1 ppm) of methyl parathion in tissue, blood, and urine is GC/FPD for phosphorus (EPA 1980d). Methyl parathion is not thermally stable above 120 °C (Keith and Walters 1985). 

Durand P, Nicaud JM, Mallevialle J. 1984. Detection of organophosphorus pesticides with an immobilized cholinesterase electrode. J Anal Toxicol 8 112-117. 

Prinsloo SM, De Beer P143R. 1985. Gas chromatographic relative retention data for pesticides on nine packed columns I. Organophosphorus pesticides, using flame photometric detection. J Assoc Off Anal Chem 68 1100-1108. 

Stan H-J, Mrowetz D. 1983. Residue analysis of organophosphorus pesticides in food with 2-dimensional gas chromatography using capillary columns and flame photometric detection. J High Resol Chromatog Chromatog Comm 6 255-263. 

Table 3 Alkylphosphates Detectable in Urine as Metabolites of Some Organophosphorus Pesticides...

Y. Lin, F. Lu, and J. Wang, Disposable carbon nanotube modified screen-printed biosensor for ampero-metric detection of organophosphorus pesticides and nerve agents. Electroanalysis 16, 145-149 (2004). 

A.Y. Kolosova, J.H. Park, S.A. Eremin, S.J. Kang and D.H. Chung, Fluorescence polarization immunoassay based on a monoclonal antibody for the detection of the organophosphorus pesticide parathion-methyl. J. Agric. Food Chem. 51, 1107-1114 (2003). 

Chau and Terry [146] reported the formation of penta-fluorobenzyl derivatives of ten herbicidal acids including 4-chloro-2-methyl-phenoxy acetic acid [145]. They found that 5h was an optimum reaction time at room temperature with pentafluorobenzyl bromide in the presence of potassium carbonate solution. Agemian and Chau [147] studied the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxy butyric acid from water samples by making the pentafluorobenzyl derivatives. Bromination [148], nitrification [149] and esterification with halogenated alcohol [145] have also been used to study the residue analysis of 4-chloro-2-methyl phenoxy acetic acid and 4-chloro-2-methyl phenoxybutyric acid. Recently pentafluorobenzyl derivatives of phenols and carboxylic acids were prepared for detection by electron capture at very low levels [150, 151]. Pentafluorobenzyl bromide has also been used for the analytical determination of organophosphorus pesticides [152],... 

Stan H-J, Kellner G. 1989. Confirmation of organophosphorus pesticide residues in food applying gas chromatography/mass spectrometry with chemical ionization and pulsed positive negative detection. Biomed and Environ Mass Spectrom 18(9) 645-651. 

Zegers BN, Hogenboom AC, Dekkers SEG, et al. 1994a. Packed capillary supercritical fluid chromatography of organophosphorus pesticides Selective detection and application. J Microcol Sep... 

Figure 14. Chromatograms of organophosphorus pesticides obtained from a small-bore fused silica column (0.2 mm i.d., 1 m long) packed with 5-pm Spherisorb ODS. A, UV detection at 254 nm and B, dual-flame thermionic detector. Peaks correspond to 1, solvent containing phosphorus impurities 2, guthion, 89 ng of phosphorus 3, zolone, 71 ng of phosphorus and 4y ethion, 144 ng of phosphorus. Mobile-phase conditions 15% water and 85% methanol (v/v) at a flow rate of 1.6 pL/min. (Reproduced from reference 58. Copyright 1983 American Chemical Society.)...

High-performance LC in the reversed-phase mode (RP-8 or RP-18 column) with UV detection (254 nm) and isocratic conditions was evaluated for the analysis of 15 organophosphorus pesticides. Typically the method could be used to analyze azinphosmethyl in water at 0.5 /rg/L. This compares favorably with GC, since this compound is very difficult to analyze by that method. For other pesticides, such as fenitrothion, which is readily analyzed by GC, the HPLC method can be used for confirmation purposes (31). 

S Lacorte, D Barcelo. Improvements in the determination of organophosphorus pesticides in ground and wastewater samples from interlaboratory studies by automated on-line liquid-solid extraction followed by liquid chromatography diode array detection. J Chromatogr A 725 85-92, 1996. 

A Lagana, G D Ascenzo, G Fago, A Marino. Determination of organophosphorus pesticides and metabolites in crops by solid phase extraction followed by liquid chromatography/diode array detection. Chromatographia 46 256-264, 1997. 

M De Paoli, TM Barbina, R Mondini, A Pezzoni, A Valentino. Determination of organophosphorus pesticides in fruits by on-line size-exclusion chromatography-liquid chromatography-gas chromatography-flame photometric detection. J Chromatogr 626 145-150, 1992. 

CG Pinto, JL Pavon, BM Cordero. Cloud point preconcentration and high performance liquid chromatographic determination of organophosphorus pesticides with dual electrochemical detection. Anal Chem 67 2606-2612, 1995. 

S. Andreescu, L. Barthelmebs and J.-L. Marty, Immobilisation of acetylcholinesterase on screen-printed electrodes comparative study between three immobilisation methods and applications to the detection of organophosphorus pesticides, Anal. Chim. Acta, 464 (2002) 171-180. 

The HPLC/MS technique used in EPA Method 8321 is best suited for analysis of thermally unstable compounds that are hard to analyze with conventional GC methods, such as organophosphorus pesticides, chlorinated herbicides, and carbamates. In this technique, the detection with mass spectrometry provides the ultimate selectivity. The sensitivity for each individual compound depends on the interferences in a given environmental matrix and on the chemical nature of the analyte. 

Salame, M., Detection and separation of the most important organophosphorus pesticides by thin-layer chromatography, J. Chromatogr., 16, 476, 1964 Chem. Abs., 62, 11090b, 1965. 

Berijani, S., Y. Assadi, M. Anbia, M.-R. Milani Hosseini, and E. Aghaee. 2006. Dispersive liquid-liquid microextraction combined with gas chromatography-flame photometric detection Very simple, rapid and sensitive method for the determination of organophosphorus pesticides in water. J. Chromatogr. A 1123 1-9. 

Lacorte and Barcelo [36] have described a procedure for the determination of nanogram per litre levels of organophosphorus pesticides in ground waters based on automated online liquid-solid extraction followed by liquid chromatography. The detection used on the liquid chromatograph is an atmospheric pressure chemical ionisation mass spectrometer using negative and positive ion modes of operation. 

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