Investigating retention characteristics of a mixed‐mode stationary phase and the enhancement of monolith selectivity for high‐performance liquid chromatography

• Published in: Journal of separation science Vol. 37; no. 15; pp. 1937 - 1943
• Main Authors: Bassanese, Danielle N, Soliven, Arianne, Stevenson, Paul G, Dennis, Gary R, Barnett, Neil W, Shalliker, Ross A, Conlan, Xavier A
• Format: Journal Article
• Language: English
• Published: Weinheim Wiley-VCH 01.08.2014; Blackwell Publishing Ltd; Wiley; Wiley Subscription Services, Inc
• Subjects: acetonitrile; Analytical chemistry; Aromatic Selectivity; Bonding; Chemical synthesis; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography; Cyano columns; Exact sciences and technology; high performance liquid chromatography; Ligands; methanol; Methyl alcohol; Methylene Selectivity; Mixed-mode columns; Other chromatographic methods; Phenyl columns; Phenyls; Polycyclic aromatic hydrocarbons; Selectivity; Separation; Silanes; Silica; Silicon dioxide; Aromatic Selectivity; Nitrile; Phase composition; Hydrocarbon; Monolithic column; HPLC chromatography; Selectivity; Phenyl columns; Polycyclic aromatic compound; Mobile phase; Cyano columns; Persistent organic pollutant; Reversed phase chromatography; Ultraviolet detector; Functionalization; Mixed-mode columns; Property structure relationship; Methylene Selectivity; Mixed adsorbent; Lipophilicity; Bonded stationary phase; Physicochemical properties; Stationary phase
• ISSN: 1615-9306; 1615-9314
• DOI: 10.1002/jssc.201400201

The synthesis and chromatographic behavior of an analytical size mixed‐mode bonded silica monolith was investigated. The monolith was functionalized by an in situ modification process of a bare silica rod with chloro(3‐cyanopropyl)dimethyl silane and chlorodimethyl propyl phenyl silane solutions. These ligands were selected in order to combine both resonance and nonresonance π‐type bonding within a single separation environment. Selectivity studies were undertaken using n‐alkyl benzenes and polycyclic aromatic hydrocarbons in aqueous methanol and acetonitrile mobile phases to assess the methylene and aromatic selectivities of the column. The results fit with the linear solvent strength theory suggesting excellent selectivity of the column was achieved. Comparison studies were performed on monolithic columns that were functionalized separately with cyano and phenyl ligands, suggesting highly conjugated molecules were able to successfully exploit both of the π‐type selectivities afforded by the two different ligands on the mixed‐mode column.