Modification of Chromatographic Method for the Determination of Benzoquinones in Cereal Products

The 2,6-dimethoxy-p-benzoquinone (2,6DMBQ) derived from different plant species is of special interest. The wheat (Triticum vulgaris) is one of the largest known natural sources of these compounds. These compounds occur in glucoside form, and are located in the embryo. In the present work we aimed at developing chromatographic method for precise, sensitive and reliable analysis with high stability of benzoquinones. In the newly worked out method RP-amide C16 column was used with 20% acetonitrile in phosphate buffer as the mobile phase. The method was validated according to calibration curve, precision and recovery tests, limit of detection and quantitation. The results indicated that as low as 0.27 lg/mL can be quantitatively determined by this method with 100.5–101%, and 97% for recovery and precision, respectively. There was significant reduction in the time required for the complete elution of phenol compounds with substantial improvement on the symmetry of their peaks as compared to those noticed with other methods. The standard and sample solutions showed higher stability at refrigeration storage for more than 4 months. As an application of the new method, fermented wheat germ, germinated wheat and extract of wheat seedlings were analysed for their benzoquinone content. The highest level was found in the fermented wheat germ, while minute quantities could be detected in the other samples.