Novel amperometric sensor using metolcarb-imprinted film as the recognition element on a gold electrode and its application NMing-Fei PanDKey Laboratory of Food Nutrition and Safety, Ministry of Education of China, Tianjin University of Science and Technology, Tianjin 300457, ChinaMpmf2006@126.com

摘要

A molecularly imprinted film is electrochemically synthesized on a gold electrode using cyclic voltam-metry to electropolymerize o-aitiinothiophenol in the presence of metolcarb (MTMC). The mechanism of the imprinting process and a number of factors affecting the activity of the imprinted film are discussed and optimized. Scanning electron microscope observations and binding measurements have proved that an MTMC-imprinted film (with a thickness of nearly l00nm) was formed on the surface of the gold electrode. The film exhibited high binding affinity and selectivity towards the template MTMC, as well as good penetrability, reproducibility and stability. A novel amperometry sensor using the imprinted film as recognition element was developed for MTMC determination in food samples. Under the experimental conditions, the MTMC standard is linear within the concentration range studied (r~2 = 0.9906). The limit of detection (S/N=3) of the modified electrode was achieved to 1.34 x 10~(-8)molL~(_1). Recoveries of MTMC from spiked apple juice, cabbage and cucumber samples for the developed electrochemical assay ranged from 94.80% to 102.43%, which was with great correlation coefficient (0.9929) with results from high-performance liquid chromatography. In practical application, the prepared amperometric sensor also showed good reproducibility and long lifetime for storage. The research in this study has offered a rapid, accurate and sensitive electrochemical method for quantitative determination of MTMC in food products.