An ultra-sensitive aptasensor based on carbon nanohorns/gold nanoparticles composites for impedimetric detection of carbendazim at picogram levels.

We reported a carbon nanohorns/gold nanoparticles composites-based impedimetric aptasensor for carbendazim (CBZ) detection in lettuce and orange juice at picogram levels. The increased electron-transfer resistance, resulting from the formation of CBZ-aptamer complex, was recorded by electrochemical impedance spectroscopy as the aptasensor response for CBZ. Under the optimal conditions, the proposed aptasensor displayed a linear response for CBZ ranging from 1 to 1000 pg mL-1 with a detection limit of 0.5 pg mL-1. Noteworthy, the as-developed aptasensor displayed the lowest detection limit for CBZ among the previously reported methods. Common pesticides (atrazine, thiamethoxam, etc.) with 100-fold concentration did not interfere the CBZ detection. For CBZ detection in lettuce and orange juice, satisfactory recoveries were obtained with standard addition method. Statistics demonstrated that no significant differences were found between the data provided by standard HPLC-MS reference method and developed aptasensing method in term of accuracy and precision. We believe that the proposed aptasensor possesses a potential application for CBZ monitoring in agricultural product and food.