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A simple and rapid electrochemical sensing method for metribuzin determination in tap and river water samples

Stojanović, Zorica, Đurović, Ana, Kravić, Snežana, Grahovac, Nada, Suturović, Zvonimir, Bursić, Vojislava, Vuković, Gorica, Brezo, Tanja
Analytical methods 2016 v.8 no.12 pp. 2698-2705
buffers, detection limit, electrochemistry, electrodes, liquid chromatography, mercury, metribuzin, pH, potassium chloride, quality control, river water, silver, silver chloride, standard deviation, tandem mass spectrometry
This paper describes an electroanalytical method for the determination of metribuzin using a thin film mercury electrode by chronopotentiometry. Research included optimization of the most important parameters of chronopotentiometric analysis and the best responses were achieved in Britton–Robinson buffer at pH 5.0, using an initial potential of −0.21 V, ending potential of −1.1 V, and reduction current in the range from −4 μA to −15 μA. Under these conditions, metribuzin was reduced in an irreversible electrode reaction process with one well-defined reduction wave at −0.83 V (vs. Ag/AgCl, KCl, 3.5 mol dm⁻³). A linear response was observed for three concentration ranges 1–5, 5–15 and 15–30 mg dm⁻³, with an achieved limit of detection of 0.042 mg dm⁻³. The precision was determined as a function of repeatability and reproducibility, which showed relative standard deviation values not higher than 3.18%. Various interfering substances did not interfere with metribuzin determination. The proposed method was successfully applied to tap and river water samples. The recovery values obtained for spiked river water samples were in good statistical agreement with those obtained by the LC-MS/MS method. Accordingly, the proposed chronopotentiometric methodology can be conveniently applied in the quality control of environmental water samples as a simple, sensitive, reliable and low cost method.