Yang Yixia,Hou Jingzhou,Huo Danqun,Wang Xianfeng,Li Jiawei,Xu Guoli,Bian Minghong,He Qiang,Hou Changjun,Yang Mei
A fluorometric method was developed for the determination of the insecticide cartap. It is based on the use of green emitting carbon dots (CDs) and gold nanoparticles (Au NPs). The CDs were prepared from phenol and ethylene diamine by a hydrothermal route. They have excitation/emission maxima at 410/513 nm) and a fluorescence quantum yield of 29%. They were characterized by TEM, Raman, XRD, XPS, FT-IR, UV and fluorescence spectroscopies. The green fluorescence of the CDs is strongly reduced by the red-colored Au NPs because of an inner filter effect. Upon addition of cartap, it will cause the aggregation of the Au NPs owing to Au-N interaction between Au NPs and cartap to form purple colored aggregates with spectra that do not overlap the green emission of the CDs. Hence, their fluorescence is restored. Under optimum conditions, the method allows for the quantitation of cartap in the 5–300 nM concentration range, and the detection limit is 3.8 nM. The method was successfully applied to the determination of cartap in spiked real samples and gave satisfactory results.
Schematic presentation of green emitting carbon dots for sensitive fluorometric determination of cartap based on its aggregation effect on gold nanoparticles.
Huixiang Wu,Changjun Hou,Huanbao Fa,Liang Dong,Yi Ma,Mei Yang,Caihong Shen,Jun Zhou,Danqun Huo
Cartap is among the most popular pesticides that are widely used to boost food production, however, its residues pose a great threat to human health and the environment. We presented simple and effective colorimetric sensor based on aggregation of gold nanoparticles (AuNPs) with appropriate diameter and fluorescent sensor via inner filter effect (IFE) of AuNPs on cadmium telluride quantum dots (CdTe QDs), respectively. Firstly, effect of diameter of AuNPs was investigated and the results indicated that AuNPs with diameter of 13 nm (AuNPs 1 3 nm ) showed better sensitivity toward cartap. Thus, AuNPs 1 3 nm was chosen for colorimetric and fluorescent cartap assay. On one hand, mercaptoacetic acid (MA) was functionalized on AuNPs 1 3 nm for the improvement of anti-disturbance ability for discrimination study. A decent linear relationship for cartap was obtained in the range from 1 μ M to 50 μ M with detection limit of 1.32 μ M for colorimetric readout; on the other hand, fluorescent sensor based on AuNPs 1 3 nm displayed excellent linear relationship with cartap concentration varying from 20 nM to 100 nM with low detection limit of 4.02 nM. And the above-mentioned sensor showed acceptable anti-disturbance ability for cartap discrimination. These results demonstrated that the sensor as-developed would be a great potential candidate for cartap detection in real application.
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