The Impact of Pesticides - Academy Publish

Sensors- A Nanotechnological Approach for the Detectionof Organophosphorous Compounds/PesticidesSanjay Upadhyay, Mukesh K. Sharma, Mahabul Shaik, Ritu Das andV.K.RaoINTRODUCTIONPesticides are chemicals designed for preventing, destroying, repelling or mitigatingany pest (insects, mice and other animals, unwanted plants, fungi, microorganisms).They are fall into three major classes: insecticides, fungicides, and herbicides (orweed killers). There are also rodenticides (for control of vertebrate pests),nematicides (to kill microscopic eelworms), molluscicides (to kill slugs and snails),and acaricides (to kill mites).Considering their chemical structure, the pesticides areorganophosphorous, carbamates, organochlorines, and pyrethroid ones (U.S. EPA,2009). OP compounds are widely used in the agriculture industry around the worldas pesticides and insecticides. Phosphorous plays a central role in the livingorganism; it is sufficient to mention photosynthesis, metabolism, and involvement incoenzyme systems etc. It can have a variety of oxidation states 3 and 5, generallyOP compounds based on their derivatives of phosphorous. Organophosphatetrimesters, phosphonates, phosphonofluoridates and phosphonothioates comprisebroad class chemical neurotoxins ((Pesticides action network, Ullmanagrochemicals) (Fig 1). However, the high toxicity of the OP compounds had notbeen recognized until the 1930s, when Lange and Krűger described effects, whichthey noticed during synthesis of some OP with the P-F bond (Holmstedt, 1963).German Chemists subsequently became interested in synthesizing insecticides.G.Schrader, in 1936, synthesized highly toxic OP insecticide ethyl-N,N-Dimethylphosphor-amidocyanidate (tabun) and iso-propylmethylphosphonofluoridate (sarin) in 1937 (Robinson & Leitenberg, 1971).Schrader synthesized the toxic OP compounds in search of better insecticides. Nerveagents are also OP compounds such as sarin (GB), tabun (GA), soman (GD) and VXare categorized as chemical warfare (CW) agents. During World War II, theGermans possessed large quantities of tabun and sarin although they were not usedin that conflict. Nerve agents are divided into two main groups: the G-agents and V-agents. The G-agents are nonpersistent (sarin, soman, & tabun) and cause casualtiesprimarily by inhalation. Sarin is highly volatile compared to tabun and soman. TheV-agents are persistent (VX) they can therefore cause casualties by both inhalationand absorption through the skin.AcademyPublish.org - The Impact of Pesticides391