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 0.35µM 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 (ΔS°, ∆H° and ∆G°) of the interaction of pesticides with the complex were evaluated.