Structural radial heterogeneity of a silica-based wide-bore monolithic column

Journal Article · Tue Jan 01 00:00:00 EST 2008 · Journal of Chromatography A

DOI:https://doi.org/10.1016/j.chroma.2008.04.004· OSTI ID:1041455

Mriziq, Khaled S ^[1]; Guiochon, Georges A ^[1]

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1. ORNL

The radial distribution of the main characteristics (elution time and standard deviation) of the elution profiles of a flat injected band recorded at the exit of a monolithic column were determined. These distributions provide the radial distributions of the average mobile phase velocity, the elution time and the maximum height of the peak of an analyte, the column efficiency and the analyte concentration. The band profiles were measured at the exit of a 10-mm i.d., 100-mm long silica-based monolithic column. An on-column local electrochemical amperometric detector allowed the recording of the elution profiles at different spatial positions throughout the column cross-section. The local spatial distribution of the mobile phase velocity does not follow a piston-flow behavior but exhibits radial heterogeneity. The local efficiency near the wall is lower than that near the column center. The radial distribution of the maximum concentration of the peaks varies throughout the column exit section, partially due to the radial variations of the column efficiency. These results might explain the rather large value of the A term of the Van Deemter or the Knox equations reported previously for monolithic columns.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 1041455
• Journal Information: Journal of Chromatography A, Vol. 1193, Issue 1-2; ISSN 0021-9673
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
EFFICIENCY
PHASE VELOCITY
SPATIAL DISTRIBUTION