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Instability of hexane–acetonitrile mobile phases used for the chromatographic analysis of triacylglycerides
Author(s) -
Harfmann Robert G.,
Julka Samir,
Cortes Hernan J.
Publication year - 2008
Publication title -
journal of separation science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.72
H-Index - 102
eISSN - 1615-9314
pISSN - 1615-9306
DOI - 10.1002/jssc.200700578
Subject(s) - chromatography , hexane , chemistry , acetonitrile , solvent , heptane , chromatographic separation , high performance liquid chromatography , organic chemistry
Comprehensive 2‐D LC is an emerging separation technique that has seen a rapid increase in applications in the last decade. The technique has been applied for the separation of numerous complex mixtures including triacylglycerides (TAG). Determination of TAG in food products such as rice, palm, and canola oils have been previously described and the technique of choice utilizes a silver‐modified silica column with hexane–ACN as the mobile phase. Repeated retention time inconsistencies were experienced in our studies when this mobile phase was applied to the separation of natural and synthetic mixtures containing TAG. The present report summarizes a study performed to determine the relative stability of ACN, propionitrile (PCN), and butyronitrile (BCN) at concentrations ranging from 0.43 to 2.8% in hexane and heptane. The data obtained suggest that unless evaporative loss of the mobile phase is prevented, TAG retention time irreproducibility can be significant when using mobile‐phase mixtures prepared with ACN or PCN. BCN should be used as the solvent modifier in cases where evaporation cannot be prevented.