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Considerations on the possibilities and limitations of comprehensive normal phase–reversed phase liquid chromatography (NPLC×RPLC)
Author(s) -
François Isabelle,
de Villiers André,
Sandra Pat
Publication year - 2006
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.200500451
Subject(s) - chromatography , chemistry , reversed phase chromatography , solvent , analytical chemistry (journal) , high performance liquid chromatography , phase (matter) , sample preparation , organic chemistry
A comprehensive normal phase system LC‐reversed phase LC (NPLC× RPLC) was evaluated for the separation of a pharmaceutical mixture and citrus oil extracts. NPLC was performed on a 25 cm×1 mm ID×5 μm d p diol phase. In the second dimension, an RP 18 monolithic column (10 cm L×4.6 mm ID×2 μm macropore size) and an octadecyl silicagel‐packed column (5 cm L×4.6 mm ID×3.5 μm d p ) were applied for the analyses of the pharmaceutical sample and the citrus oil extracts, respectively. A two‐position/ten‐port switching valve was used as interface. Under optimised LC conditions, the high degree of orthogonality between NP and RP resulted in peak capacities of 300 for the pharmaceutical sample and of 450 for the citrus oil extract composed of lemon and orange oil. Despite the features of NPLC×RPLC, several shortcomings related with the solvent incompatibility between the two LC modes were identified and the practical consequences were discussed.