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B9-OP: REFRESHABLE MERCURY FILM SILVER BASED ELECTRODE FOR VOLTAMMETRIC MONITORING OF THIAMETHOXAM INSECTICIDE IN HONEY, ACTARA 25-WG AND DANUBE WATER SAMPLES

V. Guzsvány (1), M. Putek (2), B. Tasić (1), Z. Papp (1), A. Bobrowski (2)

1 Department of Chemistry, Biochemistry and Environmental Protection, Faculty of Sciences, University of Novi Sad,
Trg D. Obradovića 3, 21000 Novi Sad, Republic of Serbia

2 Department of Building Materials Technology, Faculty of Materials Science and Ceramics,
AGH-University of Science and Technology, Mickiewicza 30, 30-059 Krakow, Poland

 

As a continuation of voltammetric studies of thiamethoxam at mercury-based electrodes [1, 2], a method has been developed for its characterization and determination by sqare wave voltammetry (SWV) using a refreshable mercury film silver based electrode (Hg(Ag)FE) [3] in aqueous solutions. The voltammetric behavior of thiamethoxam was investigated in wide pH-range of Britton-Robinson buffer (pH 2.0–9.0), as a supporting electrolyte. The most intense signals and favorable baselines were obtained in neutral and slightly alkaline solutions. Two reduction peaks of thiamethoxam appeared in an interval of approx. -0.8 to -1.4 V. The first one, probably due to the reduction of the nitro-group to hydroxylamine, was chosen for the analytical purposes. Hg(Ag)FE exhibited good analytical characteristics in respect of the peak shape and signal intensity. The optimal measuring parameters were as follows: pulse amplitude 25 mV; and polarization rate 100 mV/s. The developed direct SWV method was used to determine thiamethoxam in model solutions and selected real samples such as honey, commercial formulation Actara 25-WG and Danube water samples. Thiamethoxam could be determined at the low ppm level, while the relative standard deviation (RSD) did not exceed 2.56 %. It can be concluded that the developed metod can be used to obtain rapid information on the concentration of thiamethoxam in various complex samples.

References

1. V. Guzsvány, M. Kádár, F. Gaál, K. Tóth, L. Bjelica, Microchim. Acta, 2006, 154, 321-328.
2. V. Guzsvány, M. Kádár, F. Gaál, L. Bjelica, K. Tóth, Electroanal. 2006, 18, 1363-1371.
3. B. Bás, Z. Kowalski, Electroanal. 2002, 14, 1067-1071.