Setup and Demonstration of a Nanoelectrospray Ionization Source and Tandem Mass Spectrometry

INTRODUCTION

In this protocol, an electrospray ionization source is assembled and an empty pulled microcapillary column is connected to the assembly for infusion of a peptide sample. The microcapillary column is positioned directly in front of the opening to the mass spectrometer. Angiotensin I peptide is infused using a nanoelectrospray ionization (nanoESI) source to demonstrate the fundamentals of electrospray ionization and tandem mass spectrometry (MS/MS). The setup can also be used to tune the mass spectrometer for liquid chromatography (LC)-MS/MS experiments. After being tuned, the ion trap mass spectrometer is operated manually so that precursor scans can be performed to detect and analyze precursor ions. A selected ion is trapped and fragmented to demonstrate the principles of MS/MS.