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The effects of heating rate and sample size on the direct exposure/chemical ionization mass spectra of some biological conjugates
Author(s) -
Cotter Robert J.,
Fenselau Catherine
Publication year - 1979
Publication title -
biomedical mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0306-042X
DOI - 10.1002/bms.1200060705
Subject(s) - chemistry , mass spectrum , ion , ionization , chemical ionization , analytical chemistry (journal) , electron ionization , ambient ionization , protonation , guanosine , mass spectrometry , chromatography , organic chemistry , biochemistry
A direct exposure probe has been used to obtain mass spectra of underivatized guanosine, deoxyguanosine, sucrose and the p ‐nitrophenyl‐β‐ D ‐glucronide. In all cases, a protonated molecular ion is produced with good relative abundance. The effects of heating rate and sample size on the production of the [MH] + ion are examined in detail from total ion and single ion currents produced during rapid, repetitive scanning of the spectra after probe insertion. From this data we conclude that protonated molecular ions are produced as a result of the enhanced volatility of neutral molecules on the probe surface, followed by chemical ionization, and not by surface ionization.