Abstract: The microfluidic probe is configured for nano spray desorption electro spray ionization (nano-DESI) with fixed positioning of the channels therein for consistent and stable formation of a liquid bridge for nano-DESI and mass spectrometry imaging (MSI). The microfluidic probe may incorporate a shear force probe for sensing and maintaining a desired distance between the probe and the sample surface being analyzed. The microfluidic probe includes a primary solvent channel and a spray channel intersecting at a fixed orientation relative to each other at an opening in a tip of the probe. The microfluidic probe is constructed from a plastic material.

Abstract: The invention generally relates to mass spectral analysis. In certain embodiments, methods of the invention involve a probe for nano spray desorption electro spray ionization (nano-DESI) with fixed positioning of the channels therein for consistent and stable formation of a liquid bridge for nano-DESI and mass spectrometry imaging (MSI). Probes may incorporate a shear force probe for sensing and maintaining a desired distance between the probe and the sample surface being analyzed.