A fluorescent probe was developed and characterized, it consisted of terbium(III) with 3-ally-salicylohydrazide in ethanol, in which the 1:2 [Tb :S ] molar ratio was the best stoichiometric ratio for the probe. The ligand 3-ally-salicylohydrazide (S ) was synthesized, then was confirmed by IR, CHN, LC-MS and H NMR. The sensitivity of the probe's fluorescence spectra towards the presence of eight organophosphorus pesticides in ethanolic solution was studied, in which the probe showed marked sensitivity towards dichlorvos pesticide. A tangible enhancement of the probe's fluorescence intensity was observed as a consequence of the gradual addition of dichlorvos pesticide. The calculated limit of detection (LOD) was 1.183 μM and limit of quantitation (LOQ) was 3.94 μM. Further characterization of the nature of forces acting in the interaction of the probe with dichlorvos was performed by calculation of binding constants at different temperatures according to the Benesi - Hildebrand equation, and the thermodynamic parameters ΔH, ΔS and ΔG. In order to assess the analytical applicability of the method, the influence of various potentially interfering anion and cations that naturally occur in water and soil were calculated.

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Luminescent Europium complex based on7-hydroxy-coumarin-4-aceticas ligand was investigated as a probe for the detection of organophosphorus pesticides. The complex exhibited an interesting action towards Crotoxyphos pesticide. The luminescence of the Eu(III)-7-hydroxy-coumarin-4-acetic was remarkably enhanced by gradual addition of Crotoxyphos. Limit of detection (LOD) = 1.86 µM and limit of quantitation (LOQ) = 6.19µM. Binding constant at different temperatures was calculated according to Benesi-Hildebrand equation. The thermodynamic parameters DH, DS and DG were calculated for characterization of the nature of force due to interaction of the complex with Crotoxyphos. Finally, the effect of interfering anion and cations that naturally occur in water and soil was studied, in addition; interference of some pesticides was studied.