Evaluation of a C18 hybrid stationary phase using high-temperature chromatography

• Published in: Analytica chimica acta Vol. 554; no. 1; pp. 144 - 151
• Main Authors: Liu, Y., Grinberg, N., Thompson, K.C., Wenslow, R.M., Neue, U.D., Morrison, D., Walter, T.H., O’Gara, J.E., Wyndham, K.D.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04.12.2005; Elsevier
• Subjects: Alkyl benzenes; Analytical chemistry; Aromatic alcohols; Chemistry; Exact sciences and technology; High-temperature chromatography; Hybrid stationary phase; Thermodynamics; van Deemter plot; Thermodynamics; Hybrid stationary phase; Alkyl benzenes; Aromatic alcohols; van Deemter plot; High-temperature chromatography; Water; Differential scanning calorimetry; Stability; Toluene; Retention factor; Alcohol; High temperature; Mobile phase; Phase transitions; Chromatography; Chemical modification; Alkyl; Benzene; Thermodynamic parameter; Acetonitrile; Height equivalent to a theoretical plate; Stationary phase
• ISSN: 0003-2670; 1873-4324
• DOI: 10.1016/j.aca.2005.08.026

Alkyl benzenes and aromatic alcohols were used as model analytes in a chromatographic separation on a new type of hybrid C18 stationary phase. The stationary phase was characterized from the point of view of its interaction with the mentioned analytes. The thermodynamic parameters such as Δ H° and Δ S° showed that there are very few differences in the interactions of the alkyl benzenes and aromatic alcohols with the stationary phase in the temperature interval from 150 to 200 °C. A temperature study in the range from 30 to 200 °C using toluene as an analyte revealed that the van’t Hoff plot is non-linear. Differential scanning calorimetry studies on this stationary phase indicated a phase transition at ∼90 °C. Studies on the influence of organic modifier concentrations indicated that the retention of the analytes at 150 °C varied linearly with the volume fraction of acetonitrile in the mobile phase. At 150 °C the van Deemter plot showed that a minimum was reached for the reduced plate height at ∼1.6 mL/min which was constant up to 5 mL/min. A 1-month stability study of the column using pure water as a mobile phase, at 200 °C indicated that analyte retention factor changed by 10% during this period of time.