Electrospray from Nanostructured Tungsten Oxide Surfaces with Ultralow Sample Volume

This study demonstrated the feasibility of performing protein analysis with ultralow sample volume by combining a tungsten oxide nanowire (TON) fiber with a miniaturized electrospray ionization interface. An increase in wettability of the tugsten surface after growing randomly oriented TON on its surface allows strong adhesion of ∼50 nL of the methanol solution at its tip. Under the influence of a high electric field, electrospray from a Taylor cone on the adhered methanol solution was observed and the multiply charged ions of protein molecules predissolved in the solution were detected.