Nanoparticle MALDI-TOF Mass Spectrometry without Fragmentation: Au25(SCH2CH2Ph)18 and Mixed Monolayer Au25(SCH2CH2Ph)18−x(L)x
Citations Over TimeTop 1% of 2008 papers
Abstract
Intact molecular ions of the organothiolate-protected nanoparticle Au25(SCH2CH2Ph)18, including their isotopic resolution, can be observed at 7391 Da as 1- and 1+ ions in negative and positive mode, respectively, by MALDI-TOF mass spectrometry when using a tactic of threshold laser pulse intensities and trans-2-[3-(4-tert-butylphenyl)-2-methyl-2-propenylidene]malononitrile (DCTB) as matrix. Previous MALDI-TOF studies of Au nanoparticles using other matrices have encountered extensive fragmentation of nanoparticle as well as thiolate ligands. Absence of fragmentation enables precise determination of the distribution of mixed monolayer compositions on nanoparticles prepared by ligand exchange reactions and by synthesis using thiol mixtures. Reaction conditions producing mixed monolayers containing only one or a small number of usefully functional ligands can be readily identified. At increased laser pulse intensity, the first fragmentation step(s) for the Au25(SCH 2CH2Ph)18 nanoparticle results in losses of AuL units and, in particular, loss of Au4(SCH2CH2Ph)4.
Related Papers
- → Monolayer Behavior of Cyclic and Linear Forms of Surfactins: Thermodynamic Analysis of Langmuir Monolayers and AFM Study of Langmuir-Blodgett Monolayers(2014)13 cited
- → Stabilization of Langmuir monolayer of hydrophobic thiocholesterol molecules(2008)8 cited
- → Direct observation of defect-diminished fatty acid monolayers and their optical applications(1996)12 cited
- → On The Properties Of Surfactant Monolayers At Low Surface Tensions(2009)
- Metal-incorporated Langmuir Monolayers and Langmuir-Blodgett Films(2004)