Simultaneous determination of carbendazim and carbaryl pesticides in water bodies samples using a new voltammetric sensor based on Moringa oleifera biochar.

For the first time, a modified electrochemical sensor based on carbon paste was developed using biochar derived from the husks of Moringa oleifera pods to detect successfully and simultaneously carbendazim (CBZ) and carbaryl (CBR) pesticides. Biochar was obtained via pyrolysis at 400 °C, which required no additional activation or modification processes. The incorporation of the biochar modifier enabled the preconcentration of both pesticides under open potential circuit conditions, resulting in a significant enhancement in sensitivity compared to bare electrode. Under the optimized experimental conditions, the developed sensor exhibited excellent sensitivity to the target analytes, showing a linear relationship within the concentration range of 0.29-6.00 μM for CBZ and 29.9-502 μM for CBR. The limits of detection were calculated to be 0.12 μM for CBZ and 10.4 μM for CBR. The proposed method demonstrated remarkable selectivity for analytes even in the presence of diverse organic and inorganic species. Furthermore, the method was successfully applied to the determination of CBZ and CBR pesticides in various water matrices, including river, sea, drinking, and groundwater samples, without the need for any sample pretreatment, such as extraction or filtration. The observed recoveries ranged from 87% to 111%, indicating the efficiency and reliability of this method.