title: The assessment of pi-pi selective stationary phases for two-dimensional HPLC analysis of foods: application to the analysis of coffee.
abstract: Differences between alkyl, dipole-dipole, hydrogen bonding, and pi-pi selective surfaces represented by non-resonance and resonance pi-stationary phases have been assessed for the separation of 'Ristretto' café espresso by employing 2DHPLC techniques with C18 phase selectivity detection. Geometric approach to factor analysis (GAFA) was used to measure the detected peaks (N), spreading angle (beta), correlation, practical peak capacity (n(p)) and percentage usage of the separations space, as an assessment of selectivity differences between regional quadrants of the two-dimensional separation plane. Although all tested systems were correlated to some degree to the C18 dimension, regional measurement of separation divergence revealed that performance of specific systems was better for certain sample components. The results illustrate that because of the complexity of the 'real' sample obtaining a truly orthogonal two-dimensional system for complex samples of natural origin may be practically impossible.
authors.affiliation: Australian Centre for Research on Separation Science, University of Western Sydney Node, School of Natural Sciences, Parramatta, NSW, Australia.
authors.forename: Mariam
authors.initials: M
authors.lastname: Mnatsakanyan
authors.forename: Paul G
authors.initials: PG
authors.lastname: Stevenson
authors.forename: David
authors.initials: D
authors.lastname: Shock
authors.forename: Xavier A
authors.initials: XA
authors.lastname: Conlan
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Goodie
authors.forename: Kylie N
authors.initials: KN
authors.lastname: Spencer
authors.forename: Neil W
authors.initials: NW
authors.lastname: Barnett
authors.forename: Paul S
authors.initials: PS
authors.lastname: Francis
authors.forename: R Andrew
authors.initials: RA
authors.lastname: Shalliker
mesh_terms: D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D003069:Coffee / Q000737:chemistry*; D013058:Mass Spectrometry
chemical_list: D003069:Coffee