Spectral Measurements Of Three Kinds Of Drugs,riboflavin,aminophylline And Rutin

In this thesis,fluorescence sensors,fluorescent analysis using graphene quantum dots?GQDs?and graphene quantum dot derivatives?GQDs derivatives?as probes,Fenton chemistry and its applications were summarized.Three spectral sensors for the measurements of riboflavin?Rf?,aminophylline?AP?and rutin?RT?were developed.The amino-functionalized graphene quantum dots?afGQDs?with excellent water solubility and fluorescence properties were prepared.The quantitative analysis of Rf and AP were achieved based on the phenomenon of fluorescence quenching,and sensitive detection of RT was performed due to Fenton-like reaction and spectrophotometry.The main research contents are listed as follows.1.GQDs were synthesized via pyrolysis by using citric acid as the carbon source and the modification of amino groups generated afGQDs.AfGQDs were characterized by transmission electron microscope?TEM?,UV-vis absorption spectrum and Fourier transform infrared spectrum?FTIR?.Due to both dynamic quenching and inner filter effect,Rf could effectively quench the fluorescence of afGQDs.In the afGQDs-Rf mixture,the fluorescence intensity of afGQDs at 442 nm gradually decreased,and that at 530 nm gradually increased with the increase of Rf concentration.In pH 7.0 PBS,the ratio of the fluorescence intensity at the above two wavelengths,I₅₃₀/I₄₄₂,was linearly related to the Rf concentration in the range of 0.1-30?M with a detection limit of 0.077?M.Hence,a ratiometric fluorescent sensor for the detection of Rf was proposed.It was used to measure the content of vitamin B2 in a commercial tablet,and the recovery rate was between 97%and 106%,indicating a good accuracy.2.A new fluorescence method for the sensitive determination of AP,an antiasthmatic drug,was developed.The fluorescence of afGQDs was quenched by Rf via both dynamic quenching and inner filter effect.Photo-induced electron transfer,PET,took place between electron-abundant afGQDs and electron-deficient·OH,and it led to the further fluorescence decline.Under optimal experimental conditions,pH 7.5 PBS and 30?M Rf,the changing extent of the fluorescence intensity was found to be proportional to the concentration of AP in the range of 0.10-10?g mL^-11 and the limit of detection arrived at 40 ng mL^-1.The proposed method was successfully employed for the determination of AP in a pharmaceutical sample and the recovery rate varied in the range of 99%-106%.It suggested a high accuracy.3.A simple spectroscopic method for the measurement of rutin was developed.Fenton-like reaction between Cu²⁺and H₂O₂ could generate·OH.The latter resulted in the oxidation of 3,3',5,5'-tetramethylbenzidine?TMB?under the neutral condition and the oxidized product,TMB_ox,exhibited a new absorption peak at 652 nm.The absorption spectrum revealed that complexation reaction of RT with Cu²⁺was present.Fenton-like reaction was inhibited and the oxidation of TMB was limited when free copper ions in the solution decreased,which led to the decline of the absorbance of TMB_ox.Under the optimal experimental conditions,pH 5.5 ABS,0.3 mM c_TMB and 40-min reaction time,the absorbance change??35?A?of TMB_ox was proportional to the concentration of Rf in the range of 0.30-30?M,and the limit of detection was 0.10?M.The content of RT in a commercial tablet was determined by the developed method,and the recovery rate varied in the range of 96%-106%.Therefore,the measurement accuracy was satisfactory.