Simultaneous measurement of phytosterols (campesterol and β-sitosterol) and 7-ketocholesterol in human lipoproteins by capillary column gas chromatography
| Autor: | R.G. Dyer, C.S. Hetherington, K. G. M. M. Alberti, Michael F. Laker |
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| Rok vydání: | 1995 |
| Předmět: |
Male
Chromatography Gas Chromatography Cholesterol Lipoproteins Campesterol Phytosterols Reproducibility of Results General Chemistry BSTFA Sitosterols Sterol chemistry.chemical_compound chemistry Humans lipids (amino acids peptides and proteins) Lipoprotein oxidation Gas chromatography Ketocholesterols Oxidation-Reduction Capillary Action Saponification Lipoprotein |
| Zdroj: | Journal of Chromatography B: Biomedical Sciences and Applications. 663:1-7 |
| ISSN: | 0378-4347 |
| Popis: | 7-Ketocholesterol (a major cholesterol oxidation product) and phytosterols are important indicators of lipoprotein oxidation and lipoprotein metabolism respectively. We describe a simple, sensitive and reproducible method for the simultaneous measurement of these sterols in human lipoprotein samples by capillary column gas liquid chromatography. The method is suitable for clinical studies as small quantities of lipoprotein are required. Sterols are analysed after extraction from lipoprotein samples obtained by sequential flotation ultracentrifugation. The method involves briefly: extraction from lipoprotein samples using chloroform-methanol, saponification of sterol esters using cold potassium hydroxide, purification and derivatisation to trimethylsilyl ethers using BSTFA and 1% TMCS. Oxidation is prevented by drying under nitrogen and the use of powerful antioxidants. Separation is achieved using a DB-1 capillary column and a two-stage temperature ramp from 180-250 degrees C and detection using FID. The identity of sterols can be confirmed by GC-MS. Phytosterols and 7-ketocholesterol are present at low concentration in all the major lipoproteins. Using [3,4-13C]cholesterol and GC-MS we present evidence that cholesterol oxidation does not occur during the processing of lipoproteins using this technique. |
| Databáze: | OpenAIRE |
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