Organophosphorus Pesticides Determination by Electrochemical Biosensors

Abstract

According to the definition given by the Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA, 2008), a pesticide is any substance or mixture of substances intended for preventing, destroying, repelling or mitigating any pest (insects, mice and other animals, unwanted plants, fungi, microorganisms such as bacteria and viruses, and prions). Considering their chemical structure, the pesticides are organophosphorus, carbamates, organochlorines, and pyrethroid ones (U. S. EPA, 2009). Currently, more than 30 % of the registered pesticides in the world market (Hill, 2003) and about 45 % of those registered with U. S. Environmental Protection Agency (EPA) (Roger & Dagnac., 2006) are organophosphorus (OP). The organophosphorus pesticides, because of their high toxicity, fast biodegradation, low bioaccumulation, and broad target spectrum are extensively used in the agricultural and veterinary practices for protection of field and fruit crops, and for parasites control in domestic animals. However, their intensive and indiscriminate application, as well as their high acute toxicity generated risks to man and his environment. The resulting public concern created a demand for the development of reliable, sensitive, simple and low-costing methods for their fast “ in field” detection. In this work are reviewed the principles of the emerging electrochemical biosensors based methods for organophosphorus pesticides determination during the last decades, as methods of choice for “in situ” and “on line” application. Two main analytical techniques are considered, involving respectively the direct enzyme transformation of the pesticide and its enzyme activity inhibition effect, both followed by the conversion of the signal produced by the interaction between the bioreceptor and the analyte, into electrical one. The advantages and the drawbacks of each of them are discussed. The recent trends in the development of electrochemical biosensors for OP pesticides quantification, including nanomaterials transducer modification and genetic engineering of the biological recognition element are revised. Special attention is paid to the electrochemical biosensors based methods application for OP pesticides residues detection in food and in the environment.