A novel carbon paste electrode based on nitrogen-doped hydrothermal carbon for electrochemical determination of carbendazim [Supplementary Material]

Abstract

In this work, a new carbon paste electrode, prepared from nitrogen-doped hydrothermal carbon (CHTCN) was applied for the electrochemical detection and determination of carbendazim fungicide. CHTCN samples with the nominal nitrogen content 0.05-0.5 wt.% in glucose precursor were prepared by simple, low-cost synthesis with the accompanying carbonization to 1273 K. Presence of nitrogen in CHTCN samples was confirmed by elemental analysis. Characterization of CHTCN as material for carbon paste electrode was achieved by measurement of the Fe(CN)₆^3-/4- redox couple. The results showed that best electrochemical response was obtained for the sample with a nominal nitrogen concentration of 0.1 wt.% and tricresyl phosphate as a binder. During the development of a differential pulse stripping voltammetric method for carbendazim determination applying new electrode following experimental parameters were studied: the sort and amount of binding liquid, the effect of pH, accumulation potential and accumulation time. Under optimal conditions, electrode offered linearity in the wide concentration range from 25 to 490 ng cm^-3 and an estimated detection limit of 1.21 ng cm^-3. Moreover, the electrode showed good stability, high selectivity and satisfactory anti-interference ability. Finally, the developed method has successfully applied for the determination of carbendazim traces in spiked tap and river water samples.