35-5/Trengove.../Comparison of SFC and HPLC Separations of p-tert...

Published: Journal of Chromatographic Science, Volume 35, Number 5, May 1997, pp. 232–236.

Comparison of Supercritical Fluid Chromatographic and High-Performance Liquid Chromatographic Separations of p-tert-Butylcalix[n]arenes
B.F. Graham, J.M. Harrowfield, R.D. Trengove, I. Rodriguez, and S.F.Y. Li

Supercritical fluid chromatography (SFC) using packed analytical columns is compared with high-performance liquid chromatography (HPLC) for the separation of the readily available calixarenes, p-tert-butylcalix[4]arene, p-tert-butylcalix[6]arene, and p-tert-butylcalix[8]arene. With methanol as a modifier in supercritical carbon dioxide, p-tert-butylcalix[8]arene fails to elute from any of the four different columns used (ODS, RP-18, Cyano, and Diol), although the smaller calixarenes elute; p-tert-butylcalix[4]arene always precedes p-tert-butylcalix[6]arene. By using chloroform modifier under gradient conditions, all three can be resolved, and a retention time as short as 1.4 min is obtained for p-tert-butylcalix[8]arene on an RP-18 column. The total run time including re-equilibration is slightly over 3 min. In contrast, the shortest retention time obtained for p-tert-butylcalix[8]arene by HPLC (150-mm ODS column, 3-µm particle size, isocratic conditions, acetonitrile–ethyl acetate mobile phase [80:20]) is approximately 5 min. Peaks are both narrower and more symmetrical under SFC rather than HPLC conditions.

Reproduction of editorial content of this journal is prohibited without publisher’s permission.

This article is available in its entirety by fax for $4.00 per page.
Visa or MasterCard accepted.

To order electronically click here
or call: 847-647-2900 ext. 1323
or fax request to: 847-647-1155.

Please indicate JCS volume and issue along with page numbers.