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ELUTION OF ORGANIC SOLUTES FROM DIFFERENT POLARITY SORBENTS USING SUBCRITICAL WATER. (R825394)
Citation:
Yang, Y., M. Belghazi, A. Lagadec, D. J. Miller, AND S. B. Hawthorne. ELUTION OF ORGANIC SOLUTES FROM DIFFERENT POLARITY SORBENTS USING SUBCRITICAL WATER. (R825394). JOURNAL OF CHROMATOGRAPHY A. Elsevier Science Ltd, New York, NY, 810(1-2):149-159, (1998).
Description:
The intermolecular interactions between organic solutes and sorbent matrices under subcritical water conditions have been investigated at a pressure of 50 bar and temperatures ranging from 50 to 250°C. Both polar and nonpolar organics (chlorophenols, amines, n-alkanes, and polycyclic aromatic hydrocarbons) and five different sorbent matrices (glass beads, alumina, Florisil, silica-bonded C18, and polymeric XAD-4 resins) were used. From the same matrix, the polar solutes always eluted at lower temperatures, while the moderately polar and nonpolar solutes only eluted at higher temperatures. Similar to matrix effects previously observed using supercritical carbon dioxide, the sorbent type greatly influenced the elution efficiency under subcritical water conditions. Lower temperatures are sufficient to elute a particular solute from glass beads, alumina, and Florisil, but higher temperatures (less polar water) are needed to elute the same solute from silica-bonded C18. The highest temperatures were required to elute aromatic organics from XAD-4. These matrix effects demonstrate that, while low temperature water can break inert or dipole interactions between solutes and glass beads, alumina, and Florisil, higher temperature water is required to interrupt the van der Waals attractions between solutes and silica-bonded C18, and even higher temperatures needed to overcome the 
-electron interactions between aromatic solutes and XAD-4.
Author Keywords: Chlorophenols; Amines; Polynuclear aromatic hydrocarbons; n-Alkanes; Water, subcritical
Subject-index terms: Mobile phase composition; Stationary phases, SFC; Extraction methods