Study On The Applications Of Graphene Oxide And Graphene Quantum Dots In Chemiluminescence

Chemiluminescence(CL)method has widely used in the fields of clinical,medical,food and environmental science due to its advantages of high sensitivity,wide linear range and no external light source.Graphene oxide(GO)and graphene quantum dots(GQDs)as carbon-based nanomaterials have considerably low toxicity,low cost and eco-friendliness in addition to their comparable optical properties with other quantum dots.The combination of carbon materials and CL not only improves the sensitivity of CL but also widens the application of carbon materials.In this paper,we successfully establish the GO/GQDs-enhanced systems based on flow injection chemiluminescence(FI-CL).The results are as follows:1.GO was synthesized by Hummers method and characterization results of GO was consistent with literature reports.A new chemiluminescence(CL)system was established based on a strong CL signal between GO and luminol in alkaline solution.The possible mechanism of the GO-luminol CL system was discussed by UV-vis spectra,fluorescence spectra,CL spectra as well as some chemical experiments,the results showed that GO was possible as catalyst,oxidant or acceptor of lone pair electron to initiate the luminol CL reaction.The inhibition of the CL arised from the added puerarin(PUE)in GO-luminol CL system.So a new method for the determination of PUE was developed.Under the optimum conditions,the decrease of CL intensity was linear with the logarithm of PUE concentration in the range of 0.01–6.00 μM.The limit of detection was 2.8 nM,the relative standard deviation for 0.40 μM of PUE(n = 11)was 1.94 %.The analytical recoveries ranged from 98.0 to 102.0 % in Gegen samples and 97.0–101.5 % in human urine samples,which suggested that the proposed method can be satisfactorily used for the determination of PUE in Gegen and urine samples.2.The GQDs obtained from pyrolysis of glucose at high temperature.The fluorescent behavior of GQDs was affected by heating time,and it was found that the fluorescence quantum yield at 90 s was higher than other time.GQDs significantly enhanced the CL of KMnO4-NaHSO3 weak system under acidic conditions,so a new CL system KMnO4-NaHSO3-GQDs was established.Pefloxacin could remarkably enhance the CL intensity of KMnO4-NaHSO3-GQDs CL system.Based on the enhancing effect,a method for the determination of pefloxacin was established.Under the optimum conditions,the linear range of the net CL intensity and the concentration of pefloxacin was in the range from 0.04 to 8.00 μM,with a detection limit of 0.01 μM.The proposed method had been successfully used for the determination of pefloxacin in tables samples,the recovery were in the range of 97.5–101.8%.3.A new Ce(IV)-NaHSO3-GQDs CL system was established based on GQDs enhancing ultraweak CL system of Ce(IV)-NaHSO3 in an acidic medium.It was observed that tyrosine could inhibit the CL intensity of the Ce(IV)-NaHSO3-GQDs system.Based on this phenomenon,a new CL method for the determination of tyrosine was built.Under the optimum conditions,the CL intensity was found to be proportional to the concentration of tyrosine in the range of 0.02–8.00 μM with a detection limit of 4.1 nM.