ISSN:
0173-0835
Keywords:
Capillary electrophoresis
;
Capillary surface
;
Atomic force microscope
;
Chemistry
;
Biochemistry and Biotechnology
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
The inner surface of a fused silica capillary for zone electrophoresis was probed by the atomic force microscope (AFM) in the contact mode. Only uncoated surfaces were analyzed, after a simple washing cycle with detergent, NaOH and HCl, and final equilibration in distilled water. Three progressively larger surface areas were probed: 0.5 × 0.5 μ, 2 × 2 μm and 4 × 4 μm. In all cases, it was found that the surface is remarkably smooth, with a median height increasing from 1.3 to 5.6 nm; mean height, from 1.3 to 5.8 nm; root-mean-squared roughness, from 0.35 to 1.5 nm; and average roughness, from 0.28 to 0.67 nm (the lower values referring to the smaller area, the larger to the largest area probed). The lowest “peaks” detected are of the order of 1-2 nm; some scattered peaks as high as 16 nm are occasionally found. It is concluded that the inner surface of a capillary is not a serrate or notchy structure, but is indeed quite smooth. Since the average roughness is comprised within the thickness of the diffuse double layer (〉 10 nm) existing on the silica wall as a result of silanol ionization (and, in fact, it is on the average considerably smaller), it is concluded that it cannot possibly influence peak shape and contribute to peak decay in an electrophoretic run.
Additional Material:
5 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/elps.11501601239
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