Solid probe assisted nanoelectrospray ionization mass spectrometry for biological tissue diagnostics.

To perform remote and direct sampling for mass spectrometry, solid probe assisted nanoelectrospray ionization (SPA-nanoESI) has been newly developed. After capturing the sample on the tip of the needle by sticking it to the biological tissue, the needle was inserted into the solvent-preloaded nanoESI capillary from the backside. NanoESI gave abundant ion signals for human kidney tissues and the liver of a living mouse. The method is easy to operate and versatile because any biological specimen could be sampled away from the mass spectrometer. Minimal invasiveness is another merit of this method.