Determination of Isoflavones Using Liquid Chromatography with Electrochemical Detection

Radka Mikelová,a Petr Hodek,b Pavel Hanustiak,c,d Vojtech Adam,b Sona Krizkova,b Ladislav Havel,e Marie Stiborova,b Ales Horna,f Miroslava Beklova,d Libuse Trnkova,a Rene Kizekc,*

a Masaryk University, Department of Theoretical and Physical Chemistry, Faculty of Science, Brno, Czech Republic
Charles University, Department of Biochemistry, Faculty of Science, Prague, Czech Republic
Mendel University of Agriculture and Forestry, Department of Chemistry and Biochemistry, and
Department of Plant Biology, Faculty of Agronomy, Czech Republic.
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University of Veterinary and Pharmaceutical Sciences, Department of Veterinary Ecology and Environmental Protection, Brno, Czech Republic
Tomas Bata University, Department of Food Engineering and Chemistry, Faculty of Technology, Zlin, Czech Republic

Paper based on a presentation at the 12th International Symposium on Separation Sciences, Lipica, Slovenia,
September 27–29, 2006.

Among the biologically important roles of isoflavones is also their effect on carcinogenesis. We used flow injection analysis and high performance liquid W with electrochemical detection to simultaneously determine certain isoflavones (biochanin A, formononetin, sissotrin, daidzin, daidzein, glycitin, glycitein and genistein). The most suitable chromatographic conditions were: mobile phase: 0.2 mol L–1 acetate buffer (pH 5.0); flow rate 2.0 mL min–1; column and detector temperature: 26 °C; detection potential: 800 mV. Under the optimal conditions, the detection limits were in the range of several ng mL–1. Their simultaneous determination takes 15 min.

Keywords: isoflavone, electrochemical detection, coulometry, estrogen-like compounds, carbon paste electrode