Non-enzymatic specific detection of carbamate pesticides based on monodisperse gold-rhodium alloy nanocrystals

For the first time, monodisperse AuRh bimetallic nanocrystals are employed for the non-enzymatic specific detection of carbamate pesticides. Compared with other Au based bimetallic nanocrystals and monometallic analogues, AuRh nanocrystals show their advances in specific electrocatalytic reaction toward carbamate pesticides at nano-molar (nM) level without the assistance of acetylcholinesterase (AchE) or other biochemical recognition elements. According to the electrochemical assessments, we discover that AuRh nanocrystals have considerable response toward 1 nM carbaryl, while there is no response to organophosphorus pesticides over AuRh nanocrystals. The ultra-sensitive and highly selective detection of carbamate pesticides could be attributed to the great catalytic activity of AuRh nanocrystals toward -NH₂ group in carbamate pesticides.