Enhanced Single Molecule Mass Spectrometry Via Charged Metallic Clusters

Water-soluble metallic clusters have been used for a number of important applications. One of the most stable clusters is Au25(SG)18, which are negatively charged in solution and highly monodisperse making them ideal for characterization and analysis applications. We present here a new application where these clusters are shown to increase the mean residence time of polyethylene glycol (PEG) molecules within an alpha hemolysin (αHL) nanopore. The effect appears over a range of PEG sizes and ionic strengths. This increases the resolution of the peaks in the single molecule mass spectrometry (SMMS) current blockade distribution and suggests a means for reducing the ionic strength of the nanopore solute in the SMMS protocol.https://scholarscompass.vcu.edu/uresposters/1041/thumbnail.jp