1H NMR Quantification of Astaxanthin and Vitamin E in Nutritional Supplement

Astaxanthin (AX) and vitamin E (VE) are widely consumed nutritional supplements in China, with its beneficial effects predominantly attributed to all-trans AX and VE. The aim of this study is to develop and validate a rapid and accurate method for quantifying the content of AX and VE in nutritional supplement products using highly sensitive 1 H NMR method. Coumarin was chosen as the internal standard. Specific signals from AX was optimal at H-7,7′ in the chemical shift range of δ 6.17–6.24 ppm, whereas the signals of VE at δ 2.59 ppm. To demonstrate the reliability of this analytical approach the proposed method underwent rigorous validation, specificity, limit of detection (LOD), limit of quantitation (LOQ), linearity, accuracy, precision, and recovery. The accuracy of the validation method was 3.10% for AX and 1.99% for VE. The results indicated that the method was precise and reliable. The method has been successfully applied to simultaneous quantification of AX and VE in nutritional supplements products.