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

• The [BSmim]HSO4-AuNPs-porous carbon was firstly prepared to develop AChE biosensor.
• The lower Rct of the [BSmim]HSO4-AuNPs-porous carbon/BDD than that of the bare BDD.
• The AChE/[BSmim]HSO4-AuNPs-porous carbon/BDD biosensor showed higher sensitivity for thiocholine oxidation.
• The AChE/[BSmim]HSO4-AuNPs-porous carbon/BDD biosensor showed lower detection limit toward dichlorvos detection.
• The AChE/[BSmim]HSO4-AuNPs-porous carbon/BDD biosensor showed good repeatability and favorable stability.

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 × 10−13–4.5 × 10−9 M), with the detection limit of 6.61 × 10−11 g/L (2.99 × 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.