Azab, Hassan A. and Duerkop, Axel and Mogahed, E. M. and Awad, F. K. and Abd El Aal, R. M. and Kamel, Rasha M. (2012) Fluorescence and Electrochemical Sensing of Pesticides Methomyl, Aldicarb and Prometryne by the Luminescent Europium-3-Carboxycoumarin Probe. JOURNAL OF FLUORESCENCE, 22 (2). pp. 659-676. ISSN 1053-0509,
Full text not available from this repository. (Request a copy)Abstract
This work describes the application of time resolved fluorescence in microtiterplates and electrochemical methods on glassy carbon electrode for investigating the interactions of europium-3-carboxycoumarin with pesticides aldicarb, methomyl and prometryne. Stern-volmer studies at different temperatures indicate that static quenching dominates for methomyl, aldicarb and prometryne. By using Lineweaver-Burk equation binding constants were determined at 303 K, 308 K and 313 K. A thermodynamic analysis showed that the reaction is spontaneous with Delta G being negative. The enthalpy Delta H and the entropy Delta S of reactions were all determined. A time-resolved (gated) luminescence-based method for determination of pesticides in microtiterplate format using the long-lived europium-3-carboxycoumarin has been developed. The limit of detection is 4.80, 5.06 and 8.01 mu mol L-1 for methomyl, prometryne and aldicarb, respectively. This is the lowest limit of detection achieved so far for luminescent lanthanide-based probes for pesticides. The interaction of the probe with the pesticides has been investigated using cyclic voltammetry (CV), differential pulse polarography (DPP), square wave voltammetry (SWV) and linear sweep voltammetry (LSV) on a glassy carbon electrode in I = 0.1 mol L-1 p-toluenesulfonate at 25 A degrees C. The diffusion coefficients of the reduced species are calculated. The main properties of the electrode reaction occurring in a finite diffusion space are the quasireversible maximum and the splitting of the net SWV peak for Eu(III) ions in the ternary complex formed . It was observed that the increase of the cathodic peak currents using LSV is linear with the increase of pesticides concentration in the range 5 x 10(-7) to 1 x 10(-5) mol L-1. The detection limit (DL) were about 1.01, 2.23 and 1.89 mu molL(-1) for aldicarb, methomyl and prometryne, respectively. In order to assess the analytical applicability of the method, the influence of various potentially interfering species was examined. Influence of interfering species on the recovery of 10 mu mol L-1 pesticides has been investigated.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | SQUARE-WAVE VOLTAMMETRY; ORGANOPHOSPHORUS PESTICIDES; ENERGY-TRANSFER; EUROPIUM; EMISSION; SYSTEMS; ASSAYS; Europium-3-carboxycoumarin; Time resolved fluorescence; Pesticides aldicarb; Methomyl; Prometryne; Cyclic voltammetry; Differential pulse voltammetry; Linear sweep voltammetry; Glassy carbon electrode |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Analytische Chemie, Chemo- und Biosensorik |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 25 May 2020 04:55 |
| Last Modified: | 25 May 2020 04:55 |
| URI: | https://pred.uni-regensburg.de/id/eprint/19088 |
Actions (login required)
 |
View Item |
