Development of Nano-extractive Electrospray Ionization Mass Spectrometry for in Situ Analyses of Biological Samples

A nano-extractive electrospray ionization (nanoEESI) source was developed and coupled to a commercially linear ion trap mass spectrometer for rapid detection of amino acids and protein in complex matrices, which were manually sprayed into the electrospray plume. The limit of determination is less than 10 ng•L^－1. Experimental data show that nano-EESI-MS is a simple, fast method for in situ applications in multiple disciplines.