Hydrogen-deuterium exchange at non-labile sites is reported. The conjugate bases of isophthalic acid (m-C6H4(CO2H)2), 2-oxoglutaric acid (HO2CCOCH2CH2CO2H), and 2-methylisophthalic acid (2-CH3-1,3-C6H4(CO2H)2) undergo scrambling with 1, 2, and 3 carbon-centered hydrogens under a variety of conditions. Likewise, protonated 2-(m-methoxyphenyl)ethylamine ((m-CH3OC6H4)CH2CH2NH2) undergoes up to 5 H/D exchanges upon gentle activation whereas the conjugate acid of 2-phenylethylamine (C6H5CH2CH2NH2) requires the presence of ammonia-d3 in order to be pushed to undergo up to 8 H/D exchanges. The very act of electrospraying ions can result in extensive movement of deuterium to carbon centers and, in some cases, could not be prevented. These findings offer great promise for future exploitation but also suggest that the interpretation of many H/D exchange experiments using mass spectrometry as the analytical tool could be in error.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of the American Society for Mass Spectrometry|
|State||Published - 2001|
Bibliographical noteFunding Information:
Support from the National Science Foundation, the donors of the Petroleum Research Foundation, as administered by the American Chemical Society, and the Minnesota Supercomputer Institute are gratefully acknowledged.