Sponge-like CuInS2 microspheres on reduced graphene oxide as an electrocatalyst to construct an immobilized acetylcholinesterase electrochemical biosensor for chlorpyrifos detection in vegetables

We report a practical electrochemical biosensor for the detection of chlorpyrifos from vegetables using a new type of microsphere of CuInS2 (CIS)-linked reduced graphene oxide (rGO). The CIS microspheres offer a redox center (Cu+/In3+), large number of active sites, and high surface area. Moreover, rGO exhibits good conductivity. Thus, the microspheres of CIS and rGO can synergistically possess high affinity to acetylthiocholine chloride, decrease the number of diffusion pathways, and increase electron transfer between the thiocholine and electrode surface. The fabricated electrode showed significant sensitivity for chlorpyrifos with excellent electrochemical sensing performance, a low detection limit of 0.023 ng mL-1, and a wide linear range of 0.5?470 ng mL-1. In practice, with real samples, the CIS/rGO-based electrochemical biosensor can be successfully employed to detect chlorpyrifos in vegetables with satisfactory accuracy and acceptable recovery in the range of 96?106 %. This facile and efficient electrochemical biosensor has wide application prospects for laboratory and field experiments.

Automated summary

A practical electrochemical biosensor using copper indium sulfide and reduced graphene oxide microspheres was reported for detecting chlorpyrifos in vegetables. The sensor showed high sensitivity, low detection limit, wide linear range, and satisfactory accuracy in detecting chlorpyrifos in vegetable samples.