Development of quantum dots modified acetylcholinesterase biosensor for the detection of trichlorfon

Poly (N-vinyl-2-pyrrolidone) (PVP)-capped CdS quantum dots (QCdS-PVP) was synthesized with CdCl₂ and Na₂S in the presence of PVP. QCdS-PVP has been used for the immobilization and stabilization of the acetylcholinesterase (AChE). The electrocatalytic activity of QCdS-PVP leads to a greatly improved electrochemical detection of the enzymatically generated thiocholine product, and higher sensitivity and stability. The GCE/QCdS-PVP/AChE biosensor was used for the detection of organophosphate pesticides (OPs), such as trichlorfon. The sensor performance, including pH and inhibition time, was optimized with respect to operating conditions. Under the optimal conditions, the biosensor was used to measure as low as 12 ppb trichlorfon with a 5-min inhibition time.