Cys-AgNPs modified gold electrode as an ultrasensitive electrochemical sensor for the detection of 3-chloropropane-1,2-diol

Abstract A highly sensitive modified gold (Au) electrode using cysteine-coated silver nanoparticles (Cys-AgNPs) is designed. The electrochemical activity of this designed sensor has exhibited an excellent response for the detection of 3-chloropropane-1,2-diol (3-MCPD). Indeed, the investigation of electrochemical behavior of 3-MCPD at the Cys-AgNPs/Au electrode has shown that the electrocatalytic activity for the 3-MCPD oxidation in NaOH solution is enhanced by three-fold with the presence of Cys-AgNPs film. This Cys-AgNPs film is found to be stable on the Au electrode and the developed electrode can be reused several times while obtaining excellent results. Furthermore, using differential pulse voltammetry technique, the oxidation current peak shows a linear relationship with 3-MCPD concentration between 2.5 ng/mL and 200 ng/mL. The calculated limit of detection (LOD) and limit of quantification (LOQ) are found to be 2.4 ng/mL and 8.6 ng/mL, respectively. A recovery rate ranging from 96% to 105% in the presence of interfering compounds with similar structure to 3-MCPD or not are observed for the determination of 3-MCPD. Moreover, the developed sensor is successfully applied to the determination of 3-MCPD in smoked mackerel and palm oil samples with results which show 3-MCPD concentration ranging from 174 to 439 μg/kg and 895 to 1280 μg/kg in smoked mackerel and palm oil samples, respectively. In addition to the reusability and stability of the electrode, these results suggest that this Cys-AgNPs/Au electrode can be used as an effective sensor to monitor and determine trace level of 3-MCPD in foodstuffs.