ISSN:
0935-6304
Schlagwort(e):
Chromatography, theory
;
Peak width as a function of retention time and capacity ratio “abt” concept
;
Real plate height and theoretical plate height Extra-column contributions to band broadening and “abt” concept
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Kaiser's “abt” concept rests on the experimental establishment of a linear relation between band width at half height, b0.5, and capacity ratio, k, according to \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm b}_{{\rm 0}{\rm .5}} = {\rm b}_{\rm o} + {\rm ak} $$\end{document} His column specification quantity, hreal, is dependent on the square of the slope a, obtained from a linear regression analysis based on this relation. It is shown in the present paper that an improvement of the experimental conditions leading to a lower extra-column contribution to band broadening, bex2, introduces a tendency towards a negative curvature in the plot at low k values. The mean slope increases, and an uncritical linear regression would yield an hreal-value which is higher than before and which would be in the opposite direction to the requirements of a reliable column specification. Generally the linear regression analysis has to be moved to higher k regions in cases of curvature, especially as it is also shown that hreal is an estimation of the traditional HETP value, H∞, that would be obtained when k approaches infinity. This theoretically expected relation \documentclass{article}\pagestyle{empty}\begin{document}$$ {\rm h}_{{\rm real}} = {\rm H}_\infty $$\end{document} is a strong motivation for the use of hreal as a column specification, since the b0.5-value associated with H∞ is expected to be practically independent of bex2.
Zusätzliches Material:
1 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/jhrc.1240021205
Permalink
