Analytical Sciences

Abstract − Analytical Sciences, 25(4), 511 (2009).

Detection of Organophosphorus Pesticides Using Potentiometric Enzymatic Membrane Biosensor Based on Methylcellulose Immobilization
Jinzhong ZHANG,*1,*2 Aimin LUO,*3 Ping LIU,*1 Shaping WEI,*4 Guomin WANG,*5 and Shiqiang WEI*1,*2
*1 College of Resources and Environment, Southwest University, Chongqing 400716, P. R. China
*2 Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing 400716, P. R. China
*3 College of Light Industry, Textile & Food Engineering, Sichuan University, Chengdu 610065, P. R. China
*4 College of Chemistry and Chemical Engineering, Southwest University, Chongqing 400716, P. R. China
*5 Chongqing Entry-Exit Inspection and Quarantine Bureau, Chongqing 400020, P. R. China
In this research, a new potentiometric enzymatic membrane biosensor for the detection of organophosphorus pesticides (OPs) was constructed. The basic element of this biosensor was a pH electrode modified with an immobilized acetylcholinesterase layer formed by entrapment with methylcellulose, N,N-dimethylformamide, and bovine serum albumin. The response characteristics of the biosensor were measured and discussed. It was shown that there is a good linear relationship between the inhibition rate and the negative logarithm of OPs concentration in the range from 10-7 to 10-5 mol/L, with the detection limits of 10-7 mol/L for the five pesticides. Moreover, the biosensor could resist the disturbances of below 10-6 mol/L of Cu2+ and Pb2+, and below 10-5 mol/L of Cd2+. In addition, the measurement results obtained by the biosensor method were in good agreement with those obtained by the gas chromatography method. This method was successfully applied to detect OPs that remained in the potted lettuce.