High performance liquid chromatographic determination of alpha-tocopherol in fish liver
Hung, S.S.; Cho, Y.C.; Slinger, S.J.
Journal - Association of Official Analytical Chemists 63(4): 889-893
1980
ISSN/ISBN: 0004-5756 PMID: 7400090 Document Number: 167622
A simple method is described for the determination of .alpha.-tocopherol in fish liver by high performance liquid chromatography. This method does not involve saponification or TLC and avoids the destruction of .alpha.-tocopherol during sample preparation. The homogenized liver sample is extracted twice with dioxane-isooctane (20 + 80, vol/vol), and the combined extracts are dried under vacuum. The residue is extracted 3 times with acetonitrile from which .alpha.-tocopherol is then extracted with isooctane. The residue from the dried isooctane solution is dissolved in methanol-water (90 + 10, vol/vol) which is injected directly onto a micro Bondapak C18 high performance liquid chromatograph. The detection response to .alpha.-tocopherol at 280 nm was measured by peak height which was linear from 1 to 10 .mu.g/25 .mu.l injection. The coefficients of variation for retention time and peak height for 5 replicate analyses of the standard during 2 wk were 1.4 and 2.4%, respectively. Recovery of .alpha.-tocopherol added to the sample before homogenization was 80-92% with a mean of 86.2% and a coefficient of variation of 4.9%. The minimum amount of sample and the concentration of .alpha.-tocopherol that can be accurately determined by the method are 0.5 g liver and 1 .mu.g .alpha.-tocopherol/g liver, respectively.