The Synthesis Of Doped ZnS QDs And Its Application In Trace Analysis

In recent years，with the quantum dots (QDs) being more andmore studied by people, doped QDs also showed unique advantagesin chemical, biological, medical, materials, electronics and manyother research areas, because of its novel, unique physical andchemical properties. Over the past decade, the fluorescenceproperty of QDs has always been the focus of attention, but inpresent, the phosphorescence property also began to be concernedabout. This article focus on the synthesis of water soluble dopedZnS QDs, and take anvantage of its room-temperaturephosphorescence property to apply in detection of drugs and foodsafety.In Chapter1, the concept, luminescence properties of QDs,water soluble doped ZnS QDs, and the application of QDs in drugsand food safety have been briefly introduced.In Chapter2, a novel, rapid, simple, sensitive, preciseroom-temperature phosphorescence (RTP) quenching method wasdeveloped by Mn-doped ZnS quantum dots (QDs). The developedmethod is employed for detection of the raceanisodaminehydrochloride and atropine sulfate in biological fluids. Here, the Mn-doped ZnS QDs was capped by L-cysteine. Under the optimizedexperimental conditions, the linear range for raceanisodaminehydrochloride was0.3-9.0μM, correlation coefficient was0.9979,the detection limits (LOD) was0.11μM. The results for atropinesulfate were0.3-9.1μM,0.9974,0.09μM, respectively. Besides, therecovery of spiked solutions in human urine and serum samplesranged from95﹪to104﹪.In Chapter3, a new type of Eu (Ⅲ)-doped ZnS quantum dotscapped by L-cysteine (QDs) were synthesized in aqueous solutionand characterized through fluorescence spectrum, X-ray diffraction(XRD) and transmission electron microscope (TEM), the resultsshowed that the mean particle sizes of the QDs were about4nm,the QDs showed preferable luminescence properties and be morestable over Mn-doped ZnS QDs. In this part, a RTP method basedupon measuring the quenching of the phosphorescence intensity ofthe Eu (Ⅲ)-doped ZnS QDs was developed to detect melamine in milkproducts was also developed. The results showed that the linearrange of melamine was5-250ng·mL-1, correlation coefficient was0.9987, LOD was2.88ng·mL-1. Besides, the recovery of spikedsolutions in several milk products was96%-103%.This method hasmany advantages, such as simple, economic, precise, wider linearrange, lower LOD, and so on. It indicates that the method is full ofdevelopment prospects.