Quantitative Determination of Underivatized alpha-Tocopherol in Cow Milk, Vitamin and Multivitamin Drugs by GC-FID

A simple and rapid method for direct determination of alpha-tocopherol (alpha-T, vitamin E) in pharmaceutical preparations (vitamin and multivitamin tablets) and cow milk obtained from different villages of Erzurum in Turkey was developed and validated by GC-FID. Separation of underivatized alpha-T in pure substance, milk samples, vitamin and multivitamin tablets was performed in about 8.4 min, using an HP-5 capillary column. The range of quantification for the GC-FID was 1-30 mu g mL(-1). Within-day and between-day precision (RSD %) were less than 8.5%, and accuracy (relative error) was less than 11.0% (n = 6). LOQ and LOD values were found to be 0.35 and 0.30 mu g mL(-1), respectively. The developed method was applied directly and easily to the analysis of alpha-T in vitamin and multivitamin preparations and cow milk. RSD values were found to be 6.59% (Grandpherol soft gelatine capsule: 200 I.U.), 0.59% (Megadyn film tablet: 10 mg) and 1.54% (Supradyn drage: 10 I.U.). The developed method was also applied to cow milk samples and mean values of alpha-T content was found 2.99 mu g mL(-1) in cow milk samples. This developed and validated GC-FID method, in conjunction with other methods, could be successfully applied for routine laboratory because of its simplicity, rapidity, sensitivity, precision and accuracy.