A novel acetylcholinesterase biosensor based on ionic liquids-AuNPs-porous carbon composite matrix for detection of organophosphate pesticides

A novel acetylcholinesterase (AChE) biosensor, based on honeycomb-like hierarchically ion liquids ([BSmim]HSO4)-AuNPs-porous carbon composite modified boron-doped diamond (BDD) electrode, was developed for the detection of organophosphate pesticides. The surface morphology of the prepared ([BSmim]HSO4-AuNPs-porous carbon composite was characterized by scanning electron microscopy and transmission electron microscopy. The [BSmim] HSO4-AuNPs-porous carbon modified BDD electrode was confirmed by cyclic voltammogram and electrochemical impedance spectroscopy. For the oxidation of thiocholine, hydrolysis product of acetylthiocholine, the peak current at AChE/[BSmim] HSO4-AuNPs- porous carbon/BDD electrode is more than 4.5 times that at AChE/BDD electrode. The inhibition of dichlorvos is linearly proportional to its concentration in the range of 10(-10)-10(-6) g/L (4.5 x 10(-13)-4.5 x 10(-9) M), with the detection limit of 6.61 x 10(-11) g/L (2.99 x 10(-13) M) (calculated for 10% inhibition). The proposed biosensor provided an efficient and promising platform for the immobilization of AChE and exhibited higher sensitivity and acceptable stability for the detection of organophosphate pesticides. (C) 2015 Elsevier B.V. All rights reserved.