A modified simple method for determination of serum α-tocopherol (vitamin E).

ABSTRACT

BACKGROUND: Vitamin E is one of the important antioxidants linked to regulate various diseases, such as atherosclerosis, hypertension, and male infertility. A relatively simple and economic biochemical modified method has been developed to determine serum α-tocopherol concentration. METHODS: The current modified method is based on previous Baker and Frank method and the method of Martinek by using 2,2'-bipyridyl, ferric chloride, and xylene. The complex of ferrous ions generated in this reaction with 2,2'-bipyridyl is determined by using a plain enzyme-linked immunosorbent assay microplate (non-antibody coated) at 492 nm. RESULTS: The standard curve of this new modified method shows a linearity with correlation r=0.997 (concentration vs. absorbance). The absorbance of this color complex is directly proportional to the α-tocopherol concentration. The sensitivity of this new modified method has been compared and correlated with Baker and Frank method by using 15 human samples (r=0.99, p<0.0001). CONCLUSIONS: This simple and economic method may be routinely used to analyze α-tocopherol concentration in serum.