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

A simple and rapid method for direct determination of α-tocopherol (α-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 α-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 μg 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 μg mL−1, respectively. The developed method was applied directly and easily to the analysis of α-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 α-T content was found 2.99 μg 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.