Determination of the structure and composition of Au-Ag bimetallic spherical nanoparticles using single particle ICP-MS measurements performed with normal and high temporal resolution

Albert Kéri; Ildikó Kálomista; Ditta Ungor; Ádám Bélteki; Edit Csapó; Imre Dékány; Thomas Prohaska; Gábor Galbács

doi:10.1016/j.talanta.2017.10.056

Determination of the structure and composition of Au-Ag bimetallic spherical nanoparticles using single particle ICP-MS measurements performed with normal and high temporal resolution

Talanta. 2018 Mar 1:179:193-199. doi: 10.1016/j.talanta.2017.10.056. Epub 2017 Oct 27.

Authors

Albert Kéri¹, Ildikó Kálomista¹, Ditta Ungor², Ádám Bélteki¹, Edit Csapó³, Imre Dékány⁴, Thomas Prohaska⁵, Gábor Galbács⁶

Affiliations

¹ Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm square 7, 6720 Szeged, Hungary.
² Department of Medical Chemistry, University of Szeged, Dóm square 8, 6720 Szeged, Hungary.
³ Department of Physical Chemistry and Materials Science, University of Szeged, Aradi V. square 1, 6720 Szeged, Hungary; MTA-SZTE Biomimetic Systems Research Group, Department of Medical Chemistry, University of Szeged, Dóm square 8, 6720 Szeged, Hungary.
⁴ Department of Physical Chemistry and Materials Science, University of Szeged, Aradi V. square 1, 6720 Szeged, Hungary.
⁵ Division of Analytical Chemistry, University of Natural Resources and Life Sciences, Gregor-Mendel-Straße 33, 1180 Vienna, Austria.
⁶ Department of Inorganic and Analytical Chemistry, University of Szeged, Dóm square 7, 6720 Szeged, Hungary. Electronic address: galbx@chem.u-szeged.hu.

PMID: 29310221
DOI: 10.1016/j.talanta.2017.10.056

Abstract

In this study, the information that can be obtained by combining normal and high resolution single particle ICP-MS (spICP-MS) measurements for spherical bimetallic nanoparticles (BNPs) was assessed. One commercial certified core-shell Au-Ag nanoparticle and three newly synthesized and fully characterized homogenous alloy Au-Ag nanoparticle batches of different composition were used in the experiments as BNP samples. By scrutinizing the high resolution spICP-MS signal time profiles, it was revealed that the width of the signal peak linearly correlates with the diameter of nanoparticles. It was also observed that the width of the peak for same-size nanoparticles is always significantly larger for Au than for Ag. It was also found that it can be reliably determined whether a BNP is of homogeneus alloy or core-shell structure and that, in the case of the latter, the core comprises of which element. We also assessed the performance of several ICP-MS based analytical methods in the analysis of the quantitative composition of bimetallic nanoparticles. Out of the three methods (normal resolution spICP-MS, direct NP nebulization with solution-mode ICP-MS, and solution-mode ICP-MS after the acid dissolution of the nanoparticles), the best accuracy and precision was achieved by spICP-MS. This method allows the determination of the composition with less than 10% relative inaccuracy and better than 3% precision. The analysis is fast and only requires the usual standard colloids for size calibration. Combining the results from both quantitative and structural analyses, the core diameter and shell thickness of core-shell particles can also be calculated.

Keywords: Alloy; Bimetallic nanoparticles; Core-shell; Gold; Inductively coupled plasma mass spectrometry; Silver.