Identification of microorganisms using superconducting tunnel junctions and time-of-flight mass spectrometry

Abstract

We present time-of-flight measurements of biological material ejected from complete bacterial spores following laser irradiation.Ion impacts are registered on a microchannel plate and on a Superconducting Tunnel Junction (STJ) detector. We compare mass spectra obtained with the two detectors. The STJ has better sensitivity to massive ions and also measures the energy of each ion. We show evidence that spores of different bacillus species produce distinctive mass spectra and associate the observed mass peaks with coat proteins identified through ion-exchange extraction and gel electrophoresis.