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Molecules. 2017 Aug 28;22(9). pii: E1421. doi: 10.3390/molecules22091421.

Sensitive and Selective Detection of Oxo-Form Organophosphorus Pesticides Based on CdSe/ZnS Quantum Dots.

Wei J1, Cao J2, Hu H3,4, Yang Q5, Yang F6, Wan J7, Su H8, He C9, Li P10, Wang Y11.

Author information

1
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. wjc551@sina.com.
2
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. caojiliang126@126.com.
3
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. haohu_um@163.com.
4
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610000, Sichuan, China. haohu_um@163.com.
5
State Key Laboratory of Hydraulics and Mountain River Engineering, Sichuan University, Chengdu 610000, Sichuan, China. yuan_jia_hu@126.com.
6
School of Chemistry and Chemical Engineering, Chongqing University, Chongqing 400015, China. fengqingyang_cq@126.com.
7
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. wjbcpu@sina.com.
8
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. huanxinsu@yeah.net.
9
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. chengweihe038@163.com.
10
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. pli1978@hotmail.com.
11
State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau 999078, China. ytwang@umac.mo.

Abstract

A rapid, sensitive and enzyme-based optical biosensor was applied for the determination of seven organophosphorus pesticides (OPPs), including the oxo forms (malaoxon, paraoxon, dibrom, and dichlorvos), the thio forms (malathion and parathion) and the mixed form (demeton) in Panax ginseng. The principal of the proposed method is that the fluorescence quenching effect of quantum dots (QDs) can be observed by enzyme-generated H₂O₂. The active centers of acetylcholinesterase (AChE) could be inhibited in the presence of pesticides, which caused decrease of the generated H₂O₂. Then, the inhibition efficiency of pesticide to AChE activity could be evaluated by measuring the fluorescence changes. Different from biosensors based on immobilized enzyme or self-assembling technique, the proposed biosensor demonstrated a good selectivity for the detection of oxo forms of OPPs. In the present study, the important experimental conditions of the proposed biosensor were investigated. Under the optimized conditions (incubation temperature, 35 °C; incubation time, 20 min; pH value, 8.0; detection time, 30 min; AChE concentration, 40.9 U/L; and choline oxidase (ChOx) concentration, 637.5 U/L), the limit of detection for the investigated oxo-form OPPs was no more than 0.05 μM, which suggested that the proposed method could be used for sensitive and selective determination of trace amounts of OPPs residues in real samples with complex matrices.

KEYWORDS:

Panax ginseng; acetylcholinesterase; biosensor; organophosphorus pesticide; quantum dots

PMID:
28846648
PMCID:
PMC6151729
DOI:
10.3390/molecules22091421
[Indexed for MEDLINE]
Free PMC Article

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