?Interference? peaks in the DADI-MIKE spectra of methyl esters of benzenepolycarboxylic acids

Abstract

1. The spectra of the metastable ions (DADI spectra) of 34 benzenepolycarboxylic acid methyl esters have been studied. 2. The DADI spectra contain intense peaks of the metastable ions I-1 and I-2 with nonintegral values of the mass numbers. 3. The appearance of the I-1 and I-2 peaks in the DADI spectra of the compounds investigated is explained by the superposition on the DADI spectrum (decomposition of ions in the second field-free region) of the spectrum of ions formed as a result of processes taking place in the first field-free region of the doublefocussing mass spectrometer.