Ion sources for mass spectrometry. II. Filaments for low temperature ion sources

Abstract

Two low power filaments (thin wire rhenium-and LaB₆) have been designed to allow a chemical-ionization ion source to operate below 100°C. Both filaments simplified analysis of the thermally sensitive compound flurazepam using negative chemical-ionization mass spectrometry. The Lab₆ cathode is susceptible to poisoning from solvents with temporary loss of thermionic emission. This effect has been studied using various organic solvents.