ABSTRACT
Liquid extraction surface analysis (LESA) is a surface extraction method via a liquid droplet held in suspension allowing a novel approach for spatially resolved analysis of biological and technical surfaces of interest. LESA is a new, high-throughput tool for ambient mass spectrometry. LESA is a commercial variant of the liquid microjunction surface sampling probe developed by Van Berkel and made available on the Triversa Nanomate nanoelectrospray platform. LESA, coupled with infusion nano-electrospray high-resolution mass spectrometry and tandem mass spectrometry, is described and applied by Eikel and Henion to the qualitative determination of surface chemical residues resulting from the artificial spraying of selected fresh fruits and vegetables with representative pesticides. LESA-MS methodology is implemented to analyze five types of thermally treated meat species, namely, beef, pork, horse, chicken, and turkey meat, to select and identify heat-stable and species-specific peptide markers. The most abundant skeletal muscle proteins were identified and correctly classified according to the species following MS/MS analysis.
