The influencing factors of disposable acetylcholinesterase biosensor for in situ detection of organophosphorus pesticides

摘要

An amperometric biosensor based on acetylcholinesterase (AChE) is assembled by simple adsorption of the enzyme on screen printed electrodes. This biosensor is used to detect the inhibitory effect of organophosphorus pesticides on acetylcholinesterase activity. The detection of organophosphorus pesticides is done with acetylthiocholine chloride (ATCh) as substrate. In order to obtain the optimized response to substrate, the influencing factors of the biosensor are investigated, including temperature, pH, incubation time, substrate concentration and enzyme concentration. Under the optimized condition, that is, 500U/ml enzyme concentration, pH 7.2, 10 min incubation time, 2mM substrate concentration and temperature of 35°C, the linear range is obtained from 10"7 to I.9xlO'5M, which corresponds to 12.5~40% enzyme inhibition. The lowest detectable amount of parathion methyl is 26 ppb.