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Recent developments in the manufacturing of high performance liquid chromatography stationary phases have created polar stationary phases that have the ability to retain certain polar species. However, these stationary phases still require highly aqueous mobile phases, which cause reduced mass spectrometry (MS) sensitivity. Hydrophilic interaction liquid chromatography (HILIC), which uses a polar stationary phase, has proved to be an effective approach in improving MS sensitivity, while presenting certain drawbacks. Porous graphitic carbon can retain very polar and ionic species as well as hydrophobic analytes. Here we focus on the challenges faced with the retention of "problematic" polar species and consider the options available for their analysis. [ABSTRACT FROM AUTHOR]

The article discusses the applications of Thermo Electron Corp.'s Porous Graphitic Carbon column for ultra high temperature high performance liquid chromatography (HPLC) processes. In HPLC, the mobile phase reaches the ion source at elevated temperature which aids the vaporization and desolvation processes, thus increasing the ionization efficiency and consequently, the sensitivity of the analysis.

This article reports that limitations in the current use of 3- and 5-μm particles in high performance liquid chromatography has lead to interesting theories of how an expanded van Deemter curve can be utilized with smaller particles to increase efficiency and analysis speed. Columns packed with small particles can be operated over a wide flow-rate range, maintaining high efficiencies. Therefore, these high efficiencies enable considerable improvements in speed of analysis or in resolution. To ensure that this increase in efficiency can be converted into an increase in speed of analysis without a loss in resolution, excellent peak shapes must also be achieved. The 1.9-μm particles used in this study are built on the latest silica and bonding technology of Hypersil GOLD, already acclaimed to give excellent peaks shapes for basic pharmaceutical analytes.