Preparation of cysteine surface modified CdTe or CdTe/CdS quantum dot and method for detecting arsenic by using quantum dot

Abstract

The invention discloses a preparation method of a cysteine surface modified CdTe or CdTe / CdS quantum dot, which comprises the following steps of: under the condition of room temperature, mixing a cadmium-containing compound powder with cysteine, fully stirring and regulating the pH value to obtain a Cd precursor solution; then adding NaBH4 in Te powder, injecting an acid liquor, bringing H2Te gas generated by acidization under the action of a nitrogen flow out and introducing into the Cd precursor solution, heating for reaction and refluxing to obtain a CdTe quantum dot solution, adding Na2S solution in the CdTe quantum dot solution, and standing to obtain the cysteine surface modified CdTe / CdS nuclear shell quantum dot. The quantum dot disclosed by the invention is added in an arsenic ion-containing solution, and is subjected to fluorescent quantitative characterization by using a fluorospectro photometer to obtain a fluorescent response curve, and therefore, the qualitative or quantitative detection of the concentration of trivalent arsenic ions in a solution to be detected can be realized. The preparation method has the advantages of simpleness in operation, high sensitivity, good selectivity and the like.

Description

technical field [0001] The invention relates to the preparation of a nanometer material and its application in the detection of arsenic ions, in particular to a preparation method of a quantum dot modified on the surface of cysteine ​​and its application in the detection of arsenic. Background technique [0002] Arsenic is a non-metallic element and is one of the essential trace elements for some animals, but excessive arsenic enrichment in the body will cause poisoning, and severe cases may even be fatal. Arsenic pollution in surface water and drinking water has become one of the culprits that seriously threaten human health around the world. Relevant data show that as many as 140 million people worldwide have been exposed to arsenic-containing drinking water that exceeds the World Health Organization standard (10 ppb). Therefore, the monitoring of arsenic content in natural water bodies has attracted more and more attention. [0003] Arsenic exists in nature in the form ...

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Problems solved by technology

At the same time, the preparation of cysteine-CdTe / CdS core-shell quantum dots generally adopts a hydrothermal method (Zhang H Y, Sun P, Liu C, et al. L-Cysteine ​​capped CdTe-CdS core-shell quantum dots: preparation, characterization and immuno-labeling of HeLa cells. Luminescence, 2011, 26(2): 86-92) encapsulate water-soluble cysteine-CdTe quantum dots, but this encapsulation method has cumbersome steps, time-consuming, It is easy to cause defects such as waste of reagents, and the method used is to directly inject the Te solution reduced by NaBH4 into the Cd precursor solution, which may also introduce impurities such as boron compounds

[0006] In addition, there is no relevant report on the current method of detecting arsenic ions based on fluorescent quantum dots

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