| The methods commonly used to detect drugs are chromatographic analysis,immunoassay,sensing analysis and so on.These methods have good sensitivity and accuracy,but they also have their inherent disadvantages.The pretreatment of samples by these methods is complex,time-consuming and requires expensive instruments.Therefore,in the field of food safety and environmental protection,it is very necessary to establish a cheap,simple,rapid and sensitive drug determination method.Quantum dots(QDs)have many advantages,such as wide and continuous excitation spectrum,narrow and symmetrical emission spectrum,adjustable color and high photochemical stability.Because QDs are easy to be synthesized and characterized They can also be surface-modified and have special properties,making quantum dots gain extensive attention and research in the field of pharmaceutical analysis.However,there are few substances that can emit fluorescence and those that cannot emit fluorescence usually need to be combined with fluorescent probes or some fluorescent complexes for analysis and detection,which greatly hinders the direct use of fluorescence analysis.Because QDs contain unique fluorescent properties,they have become a new type of probe for scientists to use fluorescent labeling methods for analysis and detection.In this paper,three kinds of QDs are mainly used as luminescent materials to construct quantum dots fluorescent probes.The three drugs of sparfloxacin,methamidophos,and captopril were detected quantitatively or qualitatively,quickly and easily.The main research contents are as follows.(1)CuInS2 quantum dots modified with thioglycolic acid were prepared by hydrothermal method,and CuInS2 quantum dots were characterized by various methods such as TEM,XRD,UV-vis and so on.Based on the characteristic that CuInS2 quantum dot fluorescence intensity can be significantly quenched by sparfloxacin,a reaction system for detecting sparfloxacin was established.Meanwhile,the influence of reaction conditions(CuInS2 quantum dot concentration,pH,temperature,mixing sequence and reaction time)on the detection system was explored.The method of CuInS2 ternary quantum dot fluorescent probe for determination of sparfloxacin was established under the optimal detection conditions.This method can be used for the detection of actual samples.(2)Using citric acid as a carbon source,a one-step hydrothermal method is used to rapidly synthesize sulfur and nitrogen doping carbon quantum dots(S,N-CQDs)with good water solubility,high photoluminescence stability,and uniform size.The interaction between captopril and Cu2+forms a complex.The Cu-Captopril complex further reduces the fluorescence intensity of the system due to self-absorption,thus establishing a reaction system.According to the experimental results,there is a linear relationship between the fluorescence intensity ratio of the system before and after the addition of captopril and the concentration of the added captopril,thus establishing a new,quick and simple method for detecting captopril.(3)Carbon quantum dots functionalized with L-tyrosine methyl ester were synthesized by hydrothermal method.The experimental results show that the fluorescence intensity of L-tyrosine methyl ester functionalized carbon quantum dots can be selectively quenched by tyrosinase(TYR)and acephate inhibits the activity of tyrosinase and reduces the fluorescence quenching rate.Based on the above system,a linear equation was established to quantitatively detect Acephate,and the optimal detection conditions were discussed.At the same time,a linear equation of quenching rate with respect to the concentration of acephate Q=-0.116261gC+0.11036(C is the concentration of acephate,mg/L)was established.The detection method is convenient and efficient and can be used for actual detection... |
PDF Full Text Request