Recent Techniques Applied for Pesticides Identification and Determination in Natural Products and Its Impact to Human Health Risk

Abstract

Based on the compilation of the British Crop Protection Council, approximately 860 active substances are formulated in pesticide products currently (Tomlin, 2003). These substances belong to more than 100 substance classes. Benzoylureas, carbamates, organophosphorous compounds, pyrethroids, sulfonylureas, or triazines are the most important groups. The chemical and physical properties of these pesticides may differ considerably. There are several acidic pesticides; others are neutral or basic and some compounds contain halogens, others phosphorous, sulfur, or nitrogen. These heteroatoms may have relevance for the detection of pesticides in natural products. Pesticides such as polychlorinated biphenyls PCB’S organochlorines and organophosphates are found in various parts of the environment in quite small concentrations, but they accumulate and thus become a threat to human health and life. Maximum residue levels (or tolerances) have been established for pesticides in foodstuffs and drinking water in most countries to avoid any adverse impact on public health, and to insist on good agricultural practice. For these reasons a large number of researchers are involved in the surveillance of maximum residue levels or in the identification and quantification of pesticide residues in environmental matrices. A lot of these pesticides were registered in Egypt or most frequently detected in fruits and vegetables in Egyptian market as well as in Europe and USA. To control local, imported and exported food, multi-residue analytical methods are preferred to reduce the workload. In this study, simple and reliable multi-residue method of analysis for determination of pesticide residues in different agricultural products was developed. In this method different pesticide groups, e.g. organophosphates, moderately polar organochlorines, benzimidazoles, N-methylcarbamates and phenoxy acids could be analyzed in one multiresidue method using Liquid Chromatography tandem mass spectrometry (LCMS/MS) and fulfill the Codex and EU regulations. Grape, green beans even vegetable samples were extracted by shaking with acetonitrile .Phase separation was induced by shaking with buffer―salt mixture consisting of magnesium sulfate, sodium chloride, disodium hydrogen citrate sesquihydrate and trisodium citrate dihydrate .The sample was centrifuged and an aliquot of the clear solution dried by shaking with magnesium sulphate . The extract was centrifuged and an aliquot of the clear solution evaporated, re-dissolved in methanol/water buffer solution and injected into LC-system (Afify, 2010) .Quantitation and