β Scribed by Mark M. Robson; Mark W. Raynor; Keith D. Bartle; Anthony A. Clifford
No coin nor oath required. For personal study only.
Recent advances in techniques for the packing of microcolumns of down to 50 ΞΌm inner diameter using supercritical CO~2~ have led to rapid growth in the use of high efficiency packed capillary columns in SFC. Maximization of the usefulness and applications of these techniques requires gradient elution chromatography and the development of pumps capable of delivering 0.1 to 1 ΞΌl per minute of modifier. A micro SFCβLC pump has been tested in the isocratic and gradient elution mode with CO~2~ as the supercritical fluid and methanol as the modifier. The pump was tested using the EPA priority PAHs as the test mixture with a specially treated ODS column and UV detection. Results are presented for testing in the isocratic and gradient elution modes and the retention times are shown to have a coefficient of variation of less than 2%. The application of this system to the analysis of PAHs in coal derivatives is shown. The problems encountered in the use of formic acid as a modifier in SFC are discussed. Β© 1995 John Wiley & Sons, Inc.
π SIMILAR VOLUMES
## Abstract The need for mixed mobile phases at low flow rates suitable for capillary and packed capillary supercritical fluid chromatography (SFC) has led to the use of an air actuated high pressure prime/purge valve for onβline modifier introduction. This valve can consistently deliver small amou
## Abstract A new method to accurately deliver small amounts (0.5 to 20 mol%) of modifier into CO~2~ was used to study the effects of three different modifiers (methanol, water, and formic acid) in packed capillary column SFC. The method allows the use of different modifiers, with minimal instrumen
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