Original Paper

Analytical and Bioanalytical Chemistry

, Volume 396, Issue 3, pp 1025-1035

Laser desorption/ionization mass spectrometry analysis of monolayer-protected gold nanoparticles

  • Bo YanAffiliated withDepartment of Chemistry, University of Massachusetts
  • , Zheng-Jiang ZhuAffiliated withDepartment of Chemistry, University of Massachusetts
  • , Oscar R. MirandaAffiliated withDepartment of Chemistry, University of Massachusetts
  • , Apiwat ChompoosorAffiliated withDepartment of Chemistry, University of Massachusetts
  • , Vincent M. RotelloAffiliated withDepartment of Chemistry, University of Massachusetts Email author 
  • , Richard W. VachetAffiliated withDepartment of Chemistry, University of Massachusetts Email author 

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Abstract

Monolayer-protected gold nanoparticles (AuNPs) feature unique surface properties that enable numerous applications. Thus, there is a need for simple, rapid, and accurate methods to confirm the surface structures of these materials. Here, we describe how laser desorption/ionization mass spectrometry (LDI-MS) can be used to characterize AuNPs with neutral, positively, and negatively charged surface functional groups. LDI readily desorbs and ionizes the gold-bound ligands to produce both free thiols and disulfide ions in pure and complex samples. We also find that LDI-MS can provide a semi-quantitative measure of the ligand composition of mixed-monolayer AuNPs by monitoring mixed disulfide ions that are formed. Overall, the LDI-MS approach requires very little sample, provides an accurate measure of the surface ligands, and can be used to monitor AuNPs in complex mixtures.

http://static-content.springer.com/image/art%3A10.1007%2Fs00216-009-3250-6/MediaObjects/216_2009_3250_Figa_HTML.gif
Figure

LDI-MS analysis of ligand percentage on mixed monolayer AuNPs.

Keywords

Nanoparticles Laser desorption/ionization Mass spectrometry Surface ligands