Daidzin analysis

Murphy (1981) reported the analysis of genistin, daidzin and their aglycones and coumestrol in toasted, defatted soy flakes by HPLC without the use of external standards. Twelve extraction combinations with methanol, chloroform-methanol, acetonitrile and acetone, with or without water, and HC1 were compared. The addition of water or HC1 to the extraction solvents improved recoveries. Acetonitrile-HCl-water was found to co-extract less impurity. Based on the studies, three best... 

Eldridge (1982a,b) reported analysis of soybean and soy products using HPLC with an external standard method. They found 80% ethanol extraction for 4 hr was suitable for extraction of isoflavones from soybean, soy protein concentrate and protein isolate. They also found that daidzin and genistin accounted for 50-75% of the total isoflavones. Eldridge and Kwolek (1983) reported analysis using selected external standards and n-butyrophenone as an internal standard. 

Jones et al. (1989) developed an HPLC-UV (262 nm) method (C18 column) for analysis of phytoestrogens and coumestrol. Ethyl benzoate was used as an internal standard. The recovery rate was from 90% to 105% for daidzin and daidzein. The detection limit was approximately 20 ng based on a signal-to-noise ratio of 3 1. 

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