Determination by perfusion reversed-phase high-performance liquid chromatography of the soybean protein content of commercial soybean products prepared directly from whole soybeans

The use of soybean flour as external standard for the determination of soyb ean proteins in soybean products directly prepared from whole soybeans is i nvestigated. For that purpose a perfusion reversed-phase high-performance l iquid chromatography method consisting of a linear binary gradient acetonit rile-water (both with 0.1% trifluoroacetic acid) in 3 min at a flow-rate of 3 ml/min, and a temperature of 60 degrees C is used. Samples dissolved in water are directly injected in the chromatographic system. The method is va lidated by evaluating detection limits, precision, and accuracy and applied to the quantitation of soybean proteins in soybean products directly prepa red from whole soybeans. (C) 2000 Elsevier Science B.V. All rights reserved .