Comparison of determination methods for proanthocyanidin from grape-seed extracts

Three methods,n butyl alcohol hydrochloric acid,vanillin hydrochloric acid and vanillin sulfuric acid,were used to determine the proanthocyanidin from grape seed extracts.The different methods were compared according to the choice of standard samples and the reaction theory.As a result,the vanillin hydrochloric acid method was shown to be the best for the determination of proanthocyanidin wherein catechin was used as the standard sample,the test wavelength was 500nm,the linearity range was 10～150μg/ml,the reaction was finished at 20±1℃ for 15h,the relative standard deviation being 0.79% and the recovery was 98.1%.