Structural Elucidation of Sterols by Reversed-Phase Liquid Chromatography: I. Assignment of Retention Coefficients to Various Groups

High Performance Liquid Chromatography of Molecular Species from Free Sterols and Sterylglycosides Isolated from Oat Leaves and Seeds1

“…5). The elution sequence is in accordance with DiBussolo and Nes (1982). Striking differences concerning the avenasterols and stigmasterol are seen comparing free sterols from oat leaves with those from oat seeds.…”

“…The eluting solvents often contained higher concentrations of MeOH or other admixtures, which prevent the detection at the maximum absorption wavelength or lead to a high ground noise (Rees et al 1976, Kikuchi and Miki 1978, Colin et al 1979, Thowsen and Schroepfer 1979, Lin et al 1981. DiBussolo and Nes (1982) used acetonitrile containing 5% MeOH on a C-8 column and pure acetonitrile on a C-18 column, thus allowing a more optimal detection at Abbreviations: SG, jterylglycosides; ASG, acylsterylglycosides; MeOH, methanol; TLC, thin layer chromatography; HPLC, high performance liquid chromatography; GLC, gas liquid chromatography. " l Preliminary reports have been presented on the "4.…”

Silver ion high pressure liquid chromatography provides unprecedented separation of sterols: application to the enzymatic formation of cholesta-5,8-dien-3 beta-ol.

“…3 (14), A8, A7, and A5 sterols (42), no separations of the A8 (14) and A7 C27 sterols (43), and only slight differences in the relative retention times of the A8 and A7 C27 sterols (44). Other reports indicated little or no differences in the retention times of the A5,7, A5,24, and A8(14) sterols and little differences between the A7 and A5 sterols (45) and between A5'7'24, A7'24, A5'24, and A8 C27 sterols (46).…”

Analysis of Steryl Esters

“…These columns have led to increased sensitivity and greater resolution because of increased sterol-column interaction, which results in greater efficiency. Recently, high-performance liquid chromatography (HPLC) has proven to be a powerful tool in sterol and fatty acid research (DiBussolo and Nes, 1982;Lin et «/., 1981;Rodriguez and Parks, 1982;Taylor and Parks, 1981). However, with complex mixtures or in the interest of improving the resolution for simple mixtures, sterols are converted to trimethylsilyl ether (TMSE) derivatives (Patterson, 1984;Thompson et al, 1981).…”

“…Reverse phase refers to the finding that, contrary to conventional Chromatographie methods, the more-polar sterols have retention coefficients lower than nonpolar sterols and thus elute earlier (DiBussolo and Nes, 1982). Figure 3 illustrates how a mixture of sterols is resolved by RPLC.…”