CdSe/CdS量子点荧光探针检测大米中的镉  

Determination of cadmium in rice by functionalized CdSe /CdS quantum dots as fluorescence probe

作　　者：孟元华[1] 陶冠红[2] 

机构地区：[1]无锡市疾病预防控制中心,江苏无锡214023 [2]苏州大学材料与化学化工学部,江苏苏州215123

出　　处：《中国卫生检验杂志》2014年第2期180-182,193,共4页Chinese Journal of Health Laboratory Technology

摘　　要：目的建立一种快速测定大米中镉的方法。方法用硒粉、氧化镉、石蜡、油酸以及硫单质在有机相中合成核壳结构的CdSe/CdS,加入巯基乙酸使得油溶性的CdSe/CdS转移成水溶性的CdSe/CdS量子点。牛血清蛋白(BSA)经NaBH4还原成dBSA,然后将dBSA修饰在CdSe/CdS表面,形成dBSA-QDs。而dBSA-QDs在待测的Cd2+作用下发生荧光增强,且荧光增强程度与Cd2+的浓度之间符合Langmuir公式。实验考察了pH、温度、C dBSA/C QDs摩尔比以及高浓度的Ag+、Cu2+、Al3+、Cl-、F-、NO3-、FeF63-、Mg2+、Ca2+、Zn2+干扰离子对测定结果的影响。同时还研究了dBSA-QDs检测Cd2+的机理。结果在最优化实验条件下,方法的检出限达到8.3μg/kg,标准偏差为2.7%。将该方法用于实际大米样品的检测,与原子吸收光谱法测定结果相比,两种方法具有良好的一致性。结论该方法简单、快速且廉价,可以用大米中镉的检测。Objective To develop a new method for rapid determination of cadmium in rice samples. Methods The core - shell CdSe/CdS QDs were synthesized by using selenium powders, cadmium oxide powders, liquid paraffin, oleic acid and sul- fur power. The synthesized oil - soluble CdSe/CdS QDs was transferred into water - soluble QDs by adding mercaptoacetic acid. The dBSA was obtained by chemical reaction of BSA and NaBH4. Then dBSA was coupled to CdSe/CdS core - shell QDs to form the dBSA - QDs bioconjugates. It was found that the enhanced luminescence intensity of the dBSA - coated QDs bioconju- gates in a concentration of Cd2 ＋ dependence is best described by a Langmuir binding isotherm equation. The effect of the pH, temperature, CdBSA/CQDs molar ratio and the interference of Ag＋, Cu2＋, Al3＋, Cl-, F-, NO3 -, FeF63-, Mg2＋, Ca2＋, Zn2＋ on the fluorescence intensity of dBSA- QDs bioconjugates was investigated in the present study. In addition, the mecha- nism of Cd2 ＋ detection by dBSA - QDs was also studied. Results Under the optimized conditions, the dBSA - QDs bioconju- gates were used to detect Cd2＋ with a detection limit of 8.3μg/kg and a relative standard deviation of 2.7%. It can be used for direct analysis of rice samples, and the results were very close to those detected by AAS. Conclusion The method is simple, rapid and low -cost, it can be used to detect cadmium in rice samples.

关 键 词：量子点 大米 镉 荧光 

分 类 号：R155.51[医药卫生—营养与食品卫生学]