Laser desorption/ionization mass spectrometry analysis of monolayer-protected gold nanoparticles.
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.
Yan
Bo
B
Department of Chemistry, University of Massachusetts, Amherst, MA 01003, USA.
Zhu
Zheng-Jiang
ZJ
Miranda
Oscar R
OR
Chompoosor
Apiwat
A
Rotello
Vincent M
VM
Vachet
Richard W
RW