New probe for fluorescence detection of Azinphous ethyl, Malathion and Heptachlor pesticides

Luminescence quenching of long lived Eu(III)-Bathophenanthroline (Batho) probe of 1:2 stoichiometric ratio has been studied in acetonitrile in the presence of the pesticides Azinphous ethyl (P1), Malathion (P2) and Heptachlor (P3). The luminescence intensity of Eu(III)-(Batho)(2) probe decreases as the concentration of the pesticide increases. Direct methods for the determination of the pesticides under investigation have been developed using the luminescence quenching of Eu(III)-(Batho)(2) probe in solution. The detection limits were 0.68, 0.92 and 0.35 mu M for P1, P2 and P3, respectively. Stern-Volmer studies at different temperatures indicate that collisional quenching dominates for Azinphous ethyl, Malathion and Heptachlor. The binding constants (K) and thermodynamic parameters (Delta S degrees, Delta H degrees and Delta G degrees) of the interaction of pesticides with the complex were evaluated. (C) 2014 Elsevier B.V. All rights reserved.