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High‐temperature reversed‐phase liquid chromatography coupled to isotope ratio mass spectrometry
Author(s) -
Zhang Lijun,
Kujawinski Dorothea M.,
Jochmann Maik A.,
Schmidt Torsten C.
Publication year - 2011
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.5069
Subject(s) - chemistry , chromatography , isotope ratio mass spectrometry , mass spectrometry , analytical chemistry (journal) , detection limit , solid phase extraction , isothermal process , liquid chromatography–mass spectrometry , isotope , physics , quantum mechanics , thermodynamics
Compound‐specific isotope analysis (CSIA) by liquid chromatography coupled to isotope ratio mass spectrometry (LC/IRMS) has until now been based on ion‐exchange separation. In this work, high‐temperature reversed‐phase liquid chromatography was coupled to, and for the first time carefully evaluated for, isotope ratio mass spectrometry (HT‐LC/IRMS) with four different stationary phases. Under isothermal and temperature gradient conditions, the column bleed of XBridge C 18 (up to 180 °C), Acquity C 18 (up to 200 °C), Triart C 18 (up to 150 °C), and Zirchrom PBD (up to 150 °C) had no influence on the precision and accuracy of δ 13 C measurements, demonstrating the suitability of these columns for HT‐LC/IRMS analysis. Increasing the temperature during the LC/IRMS analysis of caffeine on two C 18 columns was observed to result in shortened analysis time. The detection limit of HT‐RPLC/IRMS obtained for caffeine was 30 mg L –1 (corresponding to 12.4 nmol carbon on‐column). Temperature‐programmed LC/IRMS (i) accomplished complete separation of a mixture of caffeine derivatives and a mixture of phenols and (ii) did not affect the precision and accuracy of δ 13 C measurements compared with flow injection analysis without a column. With temperature‐programmed LC/IRMS, some compounds that coelute at room temperature could be baseline resolved and analyzed for their individual δ 13 C values, leading to an important extension of the application range of CSIA. Copyright © 2011 John Wiley & Sons, Ltd.