科研之友
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摘要
A novel, fast and sensitive electrochemical biosensor based on biometallization and silver-enhancing for continuous signal amplification was described for the detection of organophosphate pesticide (OP). Malathion was used as a model to confirm our strategy. In this method, the immobilized acetylcholinesterase (AChE) mediated the hydrolysis of acetylthiocholine (ATCl) to yield a reducing agent thiocholine which reduced AuCl4- to form gold nanoparticles (AuNPs). The electrode was then immersed in the silver enhancer solution containing 1. 0 mol/L NH3 and 2. 0x10(-3) mol/L AgNO3, and under the condition of -0. 10 V as deposition potential, the metal silver was only deposited on the surface of AuNPs instead of the electrode surface for continuous signal amplification. The deposited silver was then quantified by linear sweep voltammetry (LSV). In the presence of malathion, the decrease in the stripping peak currents of silver was proportional to the concentration of malathion from 0. 1 mu g/L to 1000 mu g/L, and the linear equation is i(pa) = 149. 9-40. 49lgC (r = 0. 9963). The detection limit was found to be as low as 0. 05 mu g/L. The utilization of biometallization and silver deposition for continuous signal amplification to detect OP dramatically enhanced the sensitivity of AChE electrochemical biosensors. The sensor has been applied to analysis of OP in the water of Xiangjiang River with a satisfactory recovery rates ranging from 95. 5% to 102. 2%, showing a great potential for the OP assay.
- 出版日期2013-10
- 单位化学生物传感与计量学国家重点实验室; 湖南大学
