Scanning probe electrospray ionization for ambient mass spectrometry

Abstract

The method, named scanning probe electrospray ionization (SPESI), promises to be a simple and unique approach toward direct sampling and ionization methodology.

Towards Practical Endoscopic Mass Spectrometry

“…By using a suitable solvent, the compound on the surface dissolves into the solvent formed in the liquid junction interface, or liquid bridge, and is transported to the ion source such as ESI. is method has been used in "liquid sampling probe ESI" by Van Berkel et al, 22) nano desorption electrospray ionization ("nano-DESI") by Julia Laskin et al, 23) scanning probe ESI by Arakawa, 24,25) and "theta" capillary ESI probe (a double-barrel capillary that resembles the Greek letter θ "theta" when turned on end). 26) ii) Gas phase/aerosols sampling e sample is vaporized using heater or laser and the thermally desorbed sample vapor or the ablated aerosols, or both, are carried by compressed air ow or suction to the suitable ion source.…”

Reduced Sampling Size with Nanopipette for Tapping-Mode Scanning Probe Electrospray Ionization Mass Spectrometry Imaging

“…e interval between sampling and ionization can be estimated from the oscillation frequency. 10) In this study, it was assumed to be approximately 244 µs, based on the oscillation frequency of the nanopipette (4093 Hz). is interval is much shorter than that of the silica tip emitter.…”

“…9) In 2012, tapping-mode scanning probe electrospray ionization (t-SPESI), which is an ambient sampling/ionization technique that uses a single capillary probe, was reported. 10) In t-SPESI, sampling/ionization is performed by oscillating a capillary probe in which a charged solvent is owing. Sampling occurs in a liquid bridge formed between the probe apex and the sample surface, and the solution, including the chemical components that are extracted from the sample, undergoes ESI on the probe as the probe approaches the inlet of the mass spectrometer (MS inlet).…”

When API Mass Spectrometry Meets Super Atmospheric Pressure Ion Sources

“…11a, the protein solvent is 2 v/v% formic acid aqueous solution which has recently become a standard reagent for the chemical digestion. Except for the peptide fragment [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18], all other hydrolysis products are due to the cleavage at the Asp sites. Comparison was also done with acetic acids (Fig.…”

“…Although commercial instrument usually comes with an ESI or APCI source housed inside a robust chamber guarded with safety interlock, one can always open it up and turn it into an "open ion source," or replacing the original sprayer with a custom made ESI or APCI variant with novel functionality. [6][7][8][9][10][11] Such modi cation does not disturb the vacuum operating pressure, and what needs to be done is to trick the instrument so ware into believing that the "ion source is safely closed. "…”