Room Temperature Cation Exchange Reaction in Nanocrystals for Ultrasensitive Speciation Analysis of Silver Ions and Silver Nanoparticles
Room Temperature Cation Exchange Reaction in Nanocrystals for Ultrasensitive Speciation Analysis of Silver Ions and Silver Nanoparticles
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DOI：
10.1021/acs.analchem.5b00511
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发表时间：
2015-07-07
影响因子：
7.4
通讯作者：
Zheng, Chengbin
中科院分区：
文献类型：
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作者：
Huang, Ke;Xu, Kailai;Zheng, Chengbin
为了评估银纳米颗粒（AgNP）和Ag+的毒性并深入了解AgNP在环境或生物体中的转化，需要超灵敏的分析方法对其进行形态分析。在室温下，将CdTe离子纳米晶与Ag+溶液混合，在1 min内，CdTe离子纳米晶中约有40倍的Cd 2+被“轰击-爆炸”（交换），而当只存在银纳米粒子时，没有发生这种阳离子交换反应。基于这一显著差异，开发了一种用于复杂基质中Ag+和AgNPs形态分析的超灵敏方法。释放的Cd ~（2+）被四氢硼钠还原为挥发性的Cd ~（2+），分离后的Cd ~（2+）被电感耦合等离子体质谱仪（ICPMS）或原子荧光光谱仪（AFS）扫过，用于Ag ~+的间接但超灵敏的检测。ICPMS对Ag+的检测限为0.0003 μ g/L，与常规方法相比提高了100倍。相对标准偏差优于2.5%，在浓度为0.5 μ g L-1银或AgNPs，无论检测器。该方法具有灵敏度高、形态分析简单、无需有机试剂等优点，已成功应用于环境水样和草履虫细胞中Ag+和AgNPs的形态分析。
To evaluate the toxicity of silver nanoparticles (AgNPs) and Ag+ and gain deep insight into the transformation of AgNPs in the environment or organisms, ultrasensitive analytical methods are needed for their speciation analysis. About 40-fold of Cd2+ in CdTe ionic nanocrystals can be "bombarded-and-exploded" (exchanged) in less than 1 min simply by mixing the nanocrystals with Ag+ solution at room temperature, while this cation exchange reaction did not occur when only silver nanopartides were present. On the basis of this striking difference, an ultrasensitive method was developed for speciation analysis of Ag+ and AgNPs in complex matrices. The released Cd2+ was reduced to its volatile species by sodium tetrahydroborate, which was separated and swept to an inductively coupled plasma mass spectrometer (ICPMS) or an atomic fluorescence spectrometer (AFS) for the indirect but ultrasensitive detection of Ag+ Owing to the remarkable signal amplification via the cation exchange reaction and the advantages of chemical vapor generation for sampling, the limit of detection was 0.0003 mu g L-1 for Ag+ by ICPMS, which was improved by 100-fold compared to the conventional method. Relative standard deviations are better than 2.5% at a concentration of 0.5 mu g L-1 Ag or AgNPs regardless of the detector. The proposed method retains several unique advantages, including ultrahigh sensitivity, speciation analysis, simplicity and being organic reagent-free, and has been successfully utilized for speciation analysis of Ag+ and AgNPs in environmental water samples and paramecium cells.