isotope pattern

in mass spectrometry
Set of peaks related to ions with the same chemical formula but containing different isotopes; e.g. the 16 and 17 mass/charge peaks in a CH4 sample arising from 12CH4+ and 13CH4+ ions.
PAC, 1990, 62, 2167. 'Glossary of atmospheric chemistry terms (Recommendations 1990)' on page 2198 (