Nanospray desorption electrospray ionization: an ambient method for liquid-extraction surface sampling in mass spectrometry

TLDR

Nano‑DESI mass spectrometry is introduced as an ambient pressure liquid‑extraction ionization technique for analyzing organic and biological molecules on substrates. The study presents the analytical capabilities of nano‑DESI and discusses its potential for imaging applications. Nano‑DESI desorbs analytes into a solvent bridge between two capillaries, one supplying solvent to maintain the bridge and the other transporting the dissolved analyte to the mass spectrometer, while a high voltage between the inlet and primary capillary generates a self‑aspirating nanospray. The method separates desorption and ionization, enabling independent control of these steps, and demonstrates analytical capabilities with potential for imaging applications.

Abstract

Nanospray desorption electrospray ionization (nano-DESI) mass spectrometry is presented as an ambient pressure liquid extraction-ionization technique for analysis of organic and biological molecules on substrates. Analyte is desorbed into a solvent bridge formed between two capillaries and the analysis surface. One capillary supplies solvent to create and maintain the bridge, while the second capillary transports the dissolved analyte from the bridge to the mass spectrometer. A high voltage applied between the inlet of mass spectrometer and the primary capillary creates a self-aspirating nanospray. This approach enables the separation of desorption and ionization events, thus providing independent control of desorption, ionization, and transport of the analyte. We present analytical capabilities of the method and discuss its potential for imaging applications.