Mass spectrometric identification of water-soluble gold nanocluster fractions from sequential size-selective precipitation

Xiupei Yang*, Yan Su, Man Chin Paau, Martin M F CHOI

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

This paper presents a simple and convenient methodology to separate and characterize water-soluble gold nanocluster stabilized with penicillamine ligands (AuNC-SR) in aqueous medium by sequential size-selective precipitation (SSSP) and mass spectrometry (MS). The highly polydisperse crude AuNC-SR product with an average core diameter of 2.1 nm was initially synthesized by a one-phase solution method. AuNCs were then precipitated and separated successively from larger to smaller ones by progressively increasing the concentration of acetone in the aqueous AuNCs solution. The SSSP fractions were analyzed by UV-vis spectroscopy, matrix-assisted laser desorption/ionization time-of-flight-MS, and thermogravimetric analysis (TGA). The MS and TGA data confirmed that the fractions precipitated from 36, 54, 72, and 90% v/v acetone (F 36%, F 54%, F 72%, and F 90%) comprised families of close core size AuNCs with average molecular formulas of Au 38(SR) 18, Au 28(SR) 15, Au 18(SR) 12, and Au 11(SR) 8, respectively. In addition, F 36%, F 54%, F 72%, and F 90% contained also the typical magic-sized gold nanoparticles of Au 38, Au 25, Au 18, and Au 11, respectively, together with some other AuNCs. This study shed light on the potential use of SSSP for simple and large-scale preliminary separation of polydisperse water-soluble AuNCs into different fractions with a relatively narrower size distribution.

Original languageEnglish
Pages (from-to)1765-1771
Number of pages7
JournalAnalytical Chemistry
Volume84
Issue number3
DOIs
Publication statusPublished - 7 Feb 2012

Scopus Subject Areas

  • Analytical Chemistry

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