Mercaptobenzothiazole-on-Gold Organic Phase Biosensor Systems: 4. Effect of Organic Solvents on Organophosphate and Carbamate Pesticide Determination

Abstract

With an ever increasing demand for agricultural products delivered over shorter periods, we have seen the use of agricultural chemicals such as pesticides increasing in order to effectively control the damaging effects of harmful micro-organisms and insects. This has also resulted in an increase of usage of insecticides that are classified as cholinesterase (ChE) inhibitors such as organophosphates (OPs) and carbamates (CMs), to protect various crops such as bulbs, cereals, fruits, vegetables, cotton, peanuts, soybean, potato, sugar cane, coffee, alfalfa and pasture from deleterious effects. These pesticides have low environmental persistence and are highly effective as insecticides, but some exhibit potential dose-related acute and chronic toxicity in human beings by acting on the inhibition of ChE activity, followed by the accumulation of acetylcholine at cholinergic receptor sites thereby excessively stimulating the cholinergic receptors. This poses serious health effects for humans if water, processed food, fruits and vegetables with high concentrations of OPs and CMs are consumed. In children and infants it can lead to serious health effects such as as eye pain, abdominal pain, convulsions, respiratory failure, paralysis and even death (Kim et al., 2007; Liu et al., 2008; Sbai et al., 2007; Skladal et al., 1997). The toxicity of OPs and CMs are caused by their ability to bind irreversibly to the catalytic serine residue in acetylcholinesterase (AChE), which leads to inhibition of AChE that prevents nerve transmission by blocking the breakdown of the transmitter choline (Ch) (Somerset et al., 2009; Liu et al., 2008; Kim et al., 2007; Du et al., 2007; Kim et al., 2000). Since a high degree of toxicity is assigned to organophosphate (OP) and carbamate (CM) pesticide compounds, the rapid detection of these toxic chemicals in environmental samples have become increasingly important (Sbai et al., 2007; Tapsoba et al., 2009; Valdes-Ramirez et al., 2008).