A Spectrophotometric Method for the Determination of α-Tocopherol in Food and Pharmaceutical Samples Using 2-Phenyl-3-(2-Thiazolyl)-5-(2-Thiophene) Tetrazolium Bromide

Abstract

The novel reagent 2-Phenyl-3-(2-thiazolyl)-5-(2-thiophene)tetrazolium bromide (PTTT) is used in the proposed method to measure α-tocopherol in various edibles. FTIR, NMR, and mass spectral analysis were used to first synthesize and characterize PTTT. The colorless tetrazolium salt is reduced by α-tocopherol to colored formazan, which was measured quantitatively at its λmax of 537 nm. This is the only way to accurately measure α-tocopherol in different food samples. This innovative approach is used to quantitatively estimate vitamin E in a variety of edible samples because the previous methods were only applicable to pure samples and edible oils. In order to reduce tetrazolium salt by vitamin E, the sample is saponified for two hours at 70 °C in a slightly basic medium (pH 8-9). Beer's law was followed between 0.1 and 4.0 μg/mL. Sandell's sensitivity was 4.5 × 10-3 and the molar absorptivity was 9.5 × 104 L mol-1cm-1. The limits of quantification and detection were determined to be 0.21 and 0.067, respectively. The method's directness and instantaneous quantitation result make it superior to earlier approaches.