A reversed-phase high-performance liquid chromatographic method for the determination of soya bean proteins in bovine milks.

A reversed-phase high-performance liquid chromatographic method was designed for the quantitation of soya bean proteins in bovine milks. The method consisted of a linear binary gradient, acetonitrile-water-0.1% trifluoroacetic acid, at a flow rate of 1 mL/min and a temperature of 50 degrees C which resulted in a separation time for soya bean proteins of 11 min. Calibration by the external standard method using a soya bean protein isolate as standard was employed, and the method was validated by evaluating precision, accuracy, and robustness. This method was shown to be useful for the analysis of soya bean proteins in bovine milks spiked with soya bean protein isolate; soya bean protein concentrations of approximately 13 microg/g of bovine milk could be detected by using the optimized method. The results obtained for some of the bovine milks were compared with those obtained by the method of standard additions.