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High‐sensitivity liquid chromatography–combustion isotope ratio mass spectrometry of fat‐soluble vitamins
Author(s) -
Caimi Richard J.,
Brenna J. Thomas
Publication year - 1995
Publication title -
journal of mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 1076-5174
DOI - 10.1002/jms.1190300311
Subject(s) - chemistry , chromatography , mass spectrometry , combustion , isotope ratio mass spectrometry , gas chromatography , isotope , organic chemistry , physics , quantum mechanics
The sensitivity of high‐precision liquid chromatography/combustion isotope ratio mass spectrometry (LC/C‐IRMS) was improved by more than two orders of magnitude by modifications which permit optimization of flows. The lower limits for high precision are about 3 μg of analyte on‐column for flow injection and LC modes. Pneumatic aerosol spray coating was implemented and compared with simple dip coating. The signal enhancement for aerosol compared with dip coating is up fourfold at higher levels but drops to less than twofold at lower levels, while the dynamic range is extended at higher levels by fourfold at high sample load levels. LC separations for underivatized tocopherols, retinyl acetate and ergocalciferol are demonstrated with precision and accuracy of about δ 13 C < 2.5% for replicates. This work demonstrates sensitivity useful for a wide range of LC analyses and extends high‐precision LC/C‐IRMS to the determination of several fat‐soluble vitamins.