A rapid and sensitive fluoroimmunoassay based on quantum dot for the detection of chlorpyrifos residue in drinking water

Abstract

A rapid and sensitive indirect competitive fluorescence-linked immunosorbent assay (cFLISA) method based on quantum dots as the fluorescence label coupled with secondary antibody (Ab₂) for the detection of chlorpyrifos in drinking water has been developed. The cFLISA method allowed for chlorpyrifos determination in a liner working range of 15.2–205.5 ng mL⁻¹. The 50 % inhibition value (IC₅₀) and the limit of detection (LOD) of the cFLISA were 50.2 ng mL⁻¹ and 8.4 ng mL⁻¹, while the IC₅₀ and the LOD of the conventhional enzyme linked immunosorbent assay (ELISA) were 95.3 ng- mL⁻¹ and 16.2 ng mL⁻¹, respectively. When the concentrations of chlorpyrifos were 200, 100 and 50 ng mL⁻¹, the recoveries ranged from 90.8 % to 108.2 % with a coefficient of variation (CV) of 7.5 %–15.2 %. In water sample analysis, the results of cFLISA were similar to those obtained from a cELISA and a high performance liquid chromatography (HPLC) method, while the detection time by cFLISA was reduced 0.5 h compared with ELISA. It showed that cFLISA could be used as a new screening method for the detection of pesticide residue.

Keywords:

• Quantum dots
• fluorescence immunoassay
• chlorpyrifos
• drinking water

Acknowledgments

The authors gratefully acknowledge the financial support by National High Technology R&D Program of China (No. 2007AA06Z419), Natural Science Foundation of China (No. 30771810) and Science and Technology Program of Tianjin(No.09ZCKFSH02700. This work was also supported by the Cancer Institute of Tianjin, China.

Yi Ping Chen and Baoan Ning contributed equally to this work and should be treated as co-first authors.