cytellin and octadecane

Increasing the column temperature accelerates markedly elution in HPLC. The separation of five free sterols was studied on three packing materials that can withstand high temperatures. These stationary phases included graphitic carbon, a polymeric C18 silica, and a zirconia-based adsorbent. Measurements of retention data were made at up to 150 degrees C with mobile phases of different compositions. Since the columns tested afford different retention mechanisms, a variety of elution patterns were observed, with some being more advantageous than others for certain sterol separations. Effects observed include some selectivity improvements and some elution order reversals. The separation of free sterols in selected fruit juices is also presented. Albeit at the expense of a longer analysis time, the graphitic carbon column produced the best separation of the sterols in this study.

Topics: Alkanes; Beverages; Cholesterol; Chromatography, High Pressure Liquid; Citrus; Ergosterol; Graphite; Hot Temperature; Lanosterol; Sitosterols; Sterols; Stigmasterol; Zirconium

Thirteen constituents were identified from Girardinia palmata ssp ciliata C. J. Chen by using GC-MS, which amounted to 84.5% of the total peaks, the main constituent were linoleic acid (52.01%) and dimethyl fumarate (10.05%). The dissociated amino acids and KNO(3) in the sample amounted to 43.30 mg/100 g and 3.0%. Five compounds were isolated and elucidated as octadecane, hexadecylic acid, beta-sitosterol, p-coumaric acid and potasium nitrate.

Topics: Alkanes; Coumaric Acids; Dimethyl Fumarate; Fumarates; Gas Chromatography-Mass Spectrometry; Linoleic Acid; Plants, Medicinal; Propionates; Sitosterols; Urticaceae