Organophosphorous

Two examples from the analysis of water samples illustrate how a separation and preconcentration can be accomplished simultaneously. In the gas chromatographic analysis for organophosphorous pesticides in environmental waters, the analytes in a 1000-mL sample may be separated from their aqueous matrix by a solid-phase extraction using 15 mb of ethyl acetate. After the extraction, the analytes are present in the ethyl acetate at a concentration that is 67 times greater than that in... 

Nickel and Cobalt. Often present with copper in sulfuric acid leach Hquors are nickel [7440-02-0] and cobalt [7440-48-4]. Extraction using an organophosphoric acid such as D2EHPA at a moderate (3 to 4) pH can readily take out the nickel and cobalt together, leaving the copper in the aqueous phase, but the cobalt—nickel separation is more difficult (274). In the case of chloride leach Hquors, separation of cobalt from nickel is inherently simpler because cobalt, unlike nickel, has a strong tendency to form anionic chloro-complexes. Thus cobalt can be separated by amine extractants, provided the chloride content of the aqueous phase is carefully controUed. A successhil example of this approach is the Falcon-bridge process developed in Norway (274). 

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. 

Solberg, Y., and Belkin, M. (1997). The role of excitotoxieity in organophosphorous nerve agents central poisoning. Trends. Pharmacol. Set. 18(6), 183 -185. 

Moreover organophosphoric acid esters have found application as insecticides (e.g. Parathion). Some derivatives are highly toxic to man (e.g. Sarin, Soman). The organophosphonates act as inhibitors of the enzyme cholinesterase by phosphorylating it. This enzyme is involved in the proper function of the parasympathetic nervous system. A concentration of 5 x 10 g/L in the air can already cause strong toxic effects to man. 

Wild, JR USDA To develop an effective and complete biological remediation system capable of hydrolyzing organophosphorous neurotoxins from agricultural and chemical warfare munitions, contaminations, and wastes. 

Garcia-Repetto R, Martinez D, Repetto M. 1995. Coefficient of distribution of some organophosphorous pesticides in rat tissue. Vet Hum Toxicol 37 226-229. 

Pewnim T, Seifert J. 1993. Structural requirements for altering the L-tryptophan metabolism in mice by organophosphorous and methylcarbamate insecticides. Eur J Pharmacol 248 237-241. 

The inhibition of brain cholinesterase is a biomarker assay for organophosphorous (OP) and carbamate insecticides (Chapter 10, Section 10.2.4). OPs inhibit the enzyme by forming covalent bonds with a serine residue at the active center. Inhibition is, at best, slowly reversible. The degree of toxic effect depends upon the extent of cholinesterase inhibition caused by one or more OP and/or carbamate insecticides. In the case of OPs administered to vertebrates, a typical scenario is as follows sublethal symptoms begin to appear at 40-50% inhibition of cholinesterase, lethal toxicity above 70% inhibition. 

The carbamate and OP insecticides and the organophosphorous nerve gases soman, sarin, and tabun all act as anticholinesterases, and most of their toxicity is attributed to this property. The naturally occurring carbamate physostigmine, which has been used in medicine, is also an anticholinesterase. Some OP compounds can cause relatively long-lasting inhibition of the enzyme because of the phenomenon of... 

Environmental Health Criteria 63 (1986). Organophosphorous Insecticides A General Introduction. Geneva WHO. 

Eto, M. (1974). Organophosphorous Insecticides Organic and Biological Chemistry. Cleveland, OH CRC Press. 

Fest, C. and Schmidt, K.-J. (1982). Chemistry of Organophosphorous Compounds. Second edition, Berlin Springer-Verlag. 

Galloway, T. and Handy, R. (2003). Immunotoxicity of organophosphorous pesticides. Ecotoxicology 12, 345-363. 

Greig-Smith, P.W., Walker, C.H., and Thompson, H.M. (1992). Ecotoxicological consequences of interactions between avian esterases and organophosphorous compound. In B. BaUantyne and T.C. Marrs (Eds.) (1992). Clinical and Experimental Toxicology of Organophosphates and Carbamates, 295-304. Oxford, U.K. Butterworth-Heinemann. 

Hart, A.D.M. (1993). Relationships between behaviour and the inhibition of acetylcholinesterase in birds exposed to organophosphorous pesticides. Environmental Toxicology and Chemistry 12, 321-336. 

Hohnstedt, B. (1963). Structure-activity relationships of the organophosphorous anticholinesterase agents. In G.B. Keolle (Ed.) Chohnesterases and Antichohnesterase Agents. Handbuch der Experimentelle Phamacologie 15,428 85. 

Mineau, P., Fletcher, M., and Glaser, L.C. et al. (1999). Poisoning of raptors with organophosphorous and carbamate pesticides with emphasis on Canada, U.S. and U.K. Journal of Raptor Research 33, 1-37. 

Richards, R, Johnson, M., Ray, D., and Walker, C.H. (1999). Novel protein targets for organophosphorous compounds. In Esterases Reacting with Organophosphorous Compounds. E. Reiner, V. Simeon-Rudolf, and B.P. Doctor et al. (Eds.) Special Issue of Chemico-Biological Interactions 119-120. 

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