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 X 0.5 mu m, 2 X 2 mu m and 4 X 4 mu m. 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

Probing the inner surface of a capillary with the atomic force microscope

BARBERI, Riccardo Cristoforo;BARTOLINO, Roberto;
1995

Abstract

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 X 0.5 mu m, 2 X 2 mu m and 4 X 4 mu m. 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
SILICA CAPILLARIES,; ELECTROPHORESIS,; PROTEINS
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/20.500.11770/134112
 Attenzione

Attenzione! I dati visualizzati non sono stati sottoposti a validazione da parte dell'ateneo

Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 19
  • ???jsp.display-item.citation.isi??? 18
social impact