| Chemiluminescence?CL?is a conventional analytical technique with the advantages of high sensitivity,simple operation,simple instrument,no background light interference,and wide linear analysis range.It was widely used in food,chemistry,biology,environment and other fields.However,less chemiluminescence reactions limits its scope of application.Recently,nano materials as sensitizers were introduced into the weak chemiluminescent systems with the obvious enhancement.In this thesis,the effects of carbon dots?CDs?on some chemiluminescence systems was achieved for different CL system.Several analytical methods were established based on the enhancement effect of CDs on the CL systems.The main contents of this paper were as follows:?1?Europium-doped carbon quantum dots?Eu-CDs?were prepared by one-step hydrothermal method with disodium ethylenediaminetetraacetic acid?EDTA-2Na?as the carbon source,and were used in subsequent experiments.The material characterization results show that the prepared Eu-CDs had a strong ultraviolet absorption peak at 320 nm,and the optimal excitation and emission wavelengths were 320 and 390 nm.The results showed that Eu-CDs could significantly enhance the intensity of the Luminol/KMnO4 chemiluminescent system in alkaline phosphate buffered?PB?solution.Based on the strong sensitization of Ag+to the chemiluminescence system of Luminol/KMnO4/Eu-CDs,a new chemiluminescence method for the determination of trace Ag+was established.In the Luminol/KMnO4/Eu-CDs chemiluminescence system,the optimal pH of the buffer solution PB was 9.5,while the optimal concentrations of Luminol and KMnO4 were 1.0×10-55 mol L-1 and 5.0×10-66 mol L-1,respectively.In the linear range of 0.5?30 ng mL-1,the difference??I?of the chemiluminescence system had a good linear relationship with the concentration of Ag+,and its standard curve was?I=651.1+2469.2C(ng mL-1).The detection limit?3??was 0.08 ng mL-1and the relative standard deviation?RSD?was 2.1%(n=11,c=15 ng mL-1).This method was successfully applied to the detection of trace silver ions in food packaging materials,and the recovery rate was between 90.7%and 117%.?2?OVA-CDs?O-CDs?were prepared by one-step hydrothermal method using egg albumin?OVA?as carbon source,and purified for subsequent experiments.The material characterization results showed that the prepared O-CDs had weak ultraviolet absorption peaks at 270 and 320 nm.In addition,the optimal excitation and emission wavelengths of O-CDs were 300 and 420 nm,respectively.The results showed that O-CDs can significantly sensitize the ultra-weak chemiluminescence system of NaHSO3)/H2O2.Based on the inhibitory effect of tert-Butylhydroquinone?TBHQ?on the NaHSO3/H2O2/O-CDs chemiluminescence system,a new chemiluminescence method for the determination of TBHQ was established.In the NaHSO3/H2O2/O-CDs chemiluminescence system,the optimal concentration of H2O2 and NaHSO3 was 8 mmol L-1 and the concentration ratio was 1:1.The optimal dilution factor of O-CDs was 80.In the concentration range of 1.0×10-7?1.0×10-5 mol L-1,the linear relationship between the system log?I0/I?and TBHQ concentration was divided into two stages.The first standard curve was log?I0/I?=0.0649+0.0025CTBHQ(1.0×10-8 mol L-1)and the correlation coefficient?R2?was 0.9977,while the linear range was 1.0×10-7 to1.0×10-6 mol L-1.The second standard curve was log?I0/I?=0.2949+0.0005CTBHQ(1.0×10-8mol L-1)with a R2 of 0.9847,and the linear range was 1.0×10-6 to 1.0×10-5 mol L-1.The results showed that the NaHSO3/H2O2/O-CDs chemiluminescence system can be used for the detection of TBHQ.?3?Carbon quantum dots?G-CDs?were prepared by one-step hydrothermal method using ginger juice as carbon source,and purified by dialysis for subsequent experiments.The material characterization results showed that the prepared G-CDs had a strong ultraviolet absorption peak at 280 nm.In addition,the optimal excitation and emission wavelengths of G-CDs were 370 and 450 nm,respectively.X-ray photoelectron spectroscopy?XPS?results showed that G-CDs are mainly composed of carbon,nitrogen,oxygen,and sulfur.The results showed that G-CDs are significantly sensitized to the ultra-weak chemiluminescence system of sodium bicarbonate/hydrogen peroxide.Based on the inhibition effect of I–on the chemiluminescence system of NaHCO3/H2O2/G-CDs,a new method for chemiluminescence determination of I–was established.In the NaHSO3/H2O2/G-CDs chemiluminescence system,the optimized concentrations of NaHSO3 and H2O2 were 0.4 and 0.1 mol L-1,respectively.The optimal dilution ratio of G-CDs was 20.In the concentration range of 1.0×10-7?2.0×10-5 mol L-1,the linear relationship between the system log?I0/I?and I–concentration was divided into two stages.In the linear range of 1.0×10-7?4.0×10-6 mol L-1,the first standard curve was log?I0/I?=0.025+1.8×10-3C(10-7 mol/L)and the determination coefficient R2 was 0.9997.In the linear range of 4.0×10-6?2.0×10-5 mol L-1,the second standard curve was log?I0/I?=0.067+8.36×10-3C(10-7 mol/L)and the determination coefficient R2 was 0.9946.According to IUPAC regulations,the detection limit of this method was 2.6×10-8 mol L-1,and the relative standard deviation?RSD?was 2.4%(C=1.0×10-6 mol L-1,n=13).This method had been successfully applied to the detection of I–in vegetables with a recovery rate of between 93.2% and 117%. |
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