Physical evidence of two wall effects in liquid chromatography

• Published in: Journal of Chromatography Vol. 888; no. 1; pp. 1 - 12
• Main Authors: Shalliker, R.Andrew, Broyles, B.Scott, Guiochon, Georges
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 04.08.2000; Elsevier
• Subjects: Analytical chemistry; Chemistry; Chromatographic methods and physical methods associated with chromatography; Chromatography, Liquid - instrumentation; EVALUATION; Exact sciences and technology; INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; LIQUID COLUMN CHROMATOGRAPHY; Other chromatographic methods; WALL EFFECTS; Visualisation of wall effects; Wall effects; Photography; Visualization; Elution; HPLC chromatography; Optical method; Spectral band profile; Experimental study; Wall effect
• ISSN: 0021-9673
• DOI: 10.1016/S0021-9673(00)00517-3

Using optical on-column visualization for the study of the migration of sample bands, the radial variations of the local migration rate were studied in the region near the column wall. Photographs of small sample bands migrating along the column at various radial locations were obtained. On-column chromatograms extracted from these photographs showed evidence of two wall effects. The first of these effects was present only within the immediate vicinity of the wall. It is a direct result of the inability of the packing material to form a close packed configuration against the rigid column wall surface. The second wall effect causes a systematic variation of the migration rate of the sample band in the region of the wall, this rate increasing from the wall to the central region of the column. The corresponding images portrayed the classical “wall effect” that chromatographers have long discussed. They also show that this effect extends further into the column than anticipated. As to what are the relative contributions to the results of our observations of the wall effect and of a frit effect discussed in previous publications, this could not be ascertained.