Protein Sequence Analysis by Tandem Quadrupole Fourier Transform Mass Spectrometry

Abstract

Protein sequence analysis by tandem mass spectrometry (Hunt et al 1981) involves digestion of the sample by site specific reagents such as cyanogen bromide or proteolytic enzymes, partial fractionation of the resulting mixture of oligopeptides by microbore, reverse-phase, high-performance, liquid chromatography (HPLC) and direct analysis of peptides in each HPLC fraction by particle-bombardment, collision activated dissociation (Hunt et al 1986) or laser photodissociation (Hunt et al 1987), mass spectrometry on a multianalyzer instrument. Here we describe results obtained by laser photodissociation on a newly developed tandem quadrupole Fourier transform mass spectrometer (TQ-FTMS) (Hunt et al 1987). This instrument is shown schematically in Fig. 1A and consists of a standard ion source, two sets of quadrupole rods, an ion cyclotron resonance (ICR) cell housed within a 7 Tesla superconducting magnet, and an argon fluoride excimer laser for photodissociation of trapped ions.