| Carbon quantum dots are widely used in virous areas, such as analysis detection, environmental monitoring, biological imaging, drug delivery and release, diagnosis and treatment of the disease due to its excellent optical properties, good biological compatibility and low cell toxicity. In order to further expand the range of its application, especially in biomedical applications, we must continue to improve the synthetic method and technique to prepare carbon quantum dots with excellent fluorescent properties, high fluorescence quantum yield, low toxicity and good biological compatibility. At the same time, we need to study of the luminescence mechanism to provide sufficient theoretical basis for the application. In recent years, food and drug issues continue to be exposed,such as pesticide and veterinary drug residues, drug production and sale of counterfeit goods, exceeds of food additives are seriously threat to the human life and health. Therefore, it is urgent to establish accurate, rapid and sensitive detection method to common drugs and food additives. Based on the above problems, work has been carried out in this paper as follows:The fluorescent carbon quantum dots(C-dots) were synthesized by hydrothermal method using L(+)-arginine as raw material. The synthesis conditions were investigated simply. The C-dots were characterized by UV-vis absorption spectra、fluorescence spectra、fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The fluorescence of the C-dots was gradually decreased with the increase of dopamine(DA) concentrations. Based on the above phenomenon, a fluorescence sensor was designed for DA detection. A good linear relationship could be obtained between the fluorescence quenching and the concentration of DA in the range of 0.50-100.00 μM with a correlation coefficient of 0.9995 and the detection limit was 93 nM. The recoveries and relative standard deviation(RSD) were 100.29%-104.21% and 0.47%-5.42% respectively when determination the concentrations of DA in dopamine hydrochloride injection and urine.Strong fluorescent C-dots were synthesized using Gardenia as carbon source through one-step hydrothermal method. And the C-dots were characterized by UV-vis absorption spectra、fluorescence spectra、fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. Take advantage of the fluoresceng quenching induced by metronidazole(MNZ), we developed a nanosensor for sensitive detection of MNZ. Under the optimum conditions, fluorescence quenching was linearly related to the concentration of melamine in the range of 2.50-225.00 μM with a correlation coefficient of 0.9971, the detection limit was 279 nM. The recovery and precision(RSD) were 91.32%-104.37% and 0.44%-1.20%, respectively when two brands of metronidazole tablets were detected.Carbon quantum dots with yellowgreen fluorescence were synthesized by hydrothermal method using green plants aloe as carbon source. And the C-dots were characterized by UV-vis absorption spectra、fluorescence spectra、fourier transform infrared spectroscopy、 transmission electron microscopy and atomic force microscopy. With C-dots as the fluorescent molecule, the tartrazine(TZ) as a quenching agent, a simple, rapid detection of TZ fluorescent probe was established based on the principle of static quenching between the two. A good linear relationship could be obtained between the fluorescence quenching and the concentration of TZ in the range of 0.25-32.50 μM with a correlation coefficient of 0.9993 and the detection limit was 73 nM. The intra-day and inter-day recoveries were in the range of 88.56%-103.74% and 87.27%-106.60%, respectively. The intra-day and inter-day relative standard deviation(RSD) were 0.18%-3.90% and 0.37%-5.82%, respectively when determination the concentrations of TZ in real food samples. |
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