A simple and sensitive fluorescence biosensor for detection of organophosphorus pesticides using H2O2-sensitive quantum dots/bi-enzyme

• A simple and fast biosensor for detection of OPs was proposed.
• The biosensor does not need any complex process of assembly and pretreatment.
• A possible mechanism is put forward on the fluorescence quenching of CdTe QDs.
• The biosensor is suitable for the detection of residues of OPs in real examples.

In this paper, we have developed a simple, fast, convenient and sensitive method for determination of organophosphorus pesticides in real samples based on inhibition mechanism of acetylcholinesterase (AChE). The biosensor is composed of enzymes (AChE and ChOx (choline oxidase)), QDs and acetylcholine (ACh), without any complex process of assembly for biosensor. After the experimental conditions are optimized, the limit of detection (LOD) for dichlorvos (DDVP) is found to be 4.49 nM. Two linear ranges allow a wide determination of DDVP concentration from 4.49 nM to 6780 nM. Furthermore, a possible mechanism is put forward to explain the fluorescence quenching of CdTe QDs in the presence of H2O2. More importantly, the obtained biosensor is proven to be suitable for the detection of residues of organophosphorus pesticides (OPs) in real examples. The excellent performance of this biosensor will facilitate future development of rapid and high-throughput detection of organophosphorus pesticides.