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The optical stability of chiral 2-hydroxy-2-phenylacetic acid in electron ionization mass spectrometry(EIMS) process has been detected directly by deuterium labelling technique. From the EI mass spectrum of deuterated 2-hydroxy-2-phenylacetic acid, the major characteristic fragment ion at m/z 108(the capture of the carbonyl group) and the corresponding isotopic ion(13C) at m/z 109 can be observed, and the ratio of m/z=109 to m/z=108 is about 8%(the calculated value is 7.8%). As enolization of deuterated 2-hydroxy-2-phenylacetic acid in mass spectrometry can yield the characteristic fragment ion at m/z 109 and results in much higher ratio of 109/108 than 8%; this study shows that no enolization takes place during the EI-MS process of 2-hydroxy-2-phenylacetic acid. This results can be concluded that these compounds are optically stable in the process of instantaneous vaporization at high temperature and electron impact ionization.
The optical stability of chiral 2-hydroxy-2-phenylacetic acid in electron ionization mass spectrometry (EIMS) process has been detected directly by deuterium labeling technique. From the EI mass spectrum of deuterated 2-hydroxy-2-phenylacetic acid, the major characteristic fragment ion at m / z 108 (the capture of the carbonyl group) and the corresponding isotopic ion (13C) at m / z 109 can be observed, and the ratio of m / z = 109 to m / z = 108 is about 8 % (calculated value is 7.8%). As enolization of deuterated 2-hydroxy-2-phenylacetic acid in mass spectrometry can yield the characteristic fragment ion at m / z 109 and results in much higher ratio of 109/108 than 8%; This study shows that no enolization takes place during the EI-MS process of 2-hydroxy-2-phenylacetic acid. This result can be concluded that these compounds are optically stable in the process of instantaneous vaporization at high temperature and electron impact ionization.