Borovinskaya Olga, Gschwind Sabrina, Hattendorf Bodo, Tanner Martin, Günther Detlef
Department of Chemistry and Applied Biosciences, Laboratory of Inorganic Chemistry, ETH Zurich , Vladimir-Prelog-Weg 1, CH-8093 Zurich, Switzerland.
Anal Chem. 2014 Aug 19;86(16):8142-8. doi: 10.1021/ac501150c. Epub 2014 Jul 30.
This work investigated the potential of a high temporal resolution inductively coupled plasma time-of-flight mass spectrometer (ICPTOFMS) in combination with a microdroplet generator (MDG) for simultaneous mass quantification of different nanoparticles (NPs) in a mixture. For this purpose, a test system containing certified Au NPs, well characterized Ag NPs, and core-shell NPs composed of an Au core and an Ag shell was employed. Thanks to the full spectra coverage and rapid simultaneous detection of the TOFMS, the element composition of individual particles can be determined. The pure Ag NPs and the core-shell NPs could be differentiated despite the same mass of Ag they contain. Calibration with monodisperse droplets consisting of standard solutions allowed for the mass quantification of NPs without the use of NP certified materials. On the basis of this mass quantification, the sizes of NPs originating from the same aqueous suspension were simultaneously determined with an accuracy of 7-12%. The size-equivalent limits of detection estimated with the 3*σ criterion were 13 nm for Au and 16 nm for Ag. Estimation of the LODs using Poisson statistics resulted in 19 and 27 nm, respectively. In addition, the 30 μs temporal resolution of the ICPTOFMS allowed studying interactions of NPs with the ICP based on their transient MS signals. The results demonstrated a difference in vaporization behavior of the core-shell NPs and solutions and indicated that vaporization of the Ag shell takes place prior to the Au core.
本研究考察了高时间分辨率电感耦合等离子体飞行时间质谱仪（ICP-TOFMS）与微滴发生器（MDG）联用，对混合物中不同纳米颗粒（NP）进行同时定量分析的潜力。为此，采用了一个测试系统，其中包含经过认证的金纳米颗粒、表征良好的银纳米颗粒以及由金核和银壳组成的核壳纳米颗粒。借助飞行时间质谱仪的全谱覆盖和快速同时检测功能，可以确定单个颗粒的元素组成。尽管纯银纳米颗粒和核壳纳米颗粒所含银的质量相同，但仍可将它们区分开来。使用由标准溶液组成的单分散液滴进行校准，无需使用经过认证的纳米颗粒材料即可对纳米颗粒进行质量定量。基于这种质量定量，同时测定了来自同一水悬浮液的纳米颗粒的尺寸，准确度为7%-12%。用3*σ标准估计的尺寸等效检测限，金为13 nm，银为16 nm。用泊松统计估计检测限时，结果分别为19 nm和27 nm。此外，ICP-TOFMS的30 μs时间分辨率使得能够基于纳米颗粒的瞬态质谱信号研究其与电感耦合等离子体的相互作用。结果表明，核壳纳米颗粒与溶液的汽化行为存在差异，且银壳的汽化先于金核发生。
