Analysis of aromatic plant acids by capillary zone electrophoresis

The use of capillary zone electrophoresis is described for the separation and identification of selected mixtures of aromatic plant acids. The influence of voltage, temperature, buffer systems and buffer pH on the migration order and migration times was investigated. The best separation was obtained with a fused-silica capillary column (64.5 cmX50 mu m I.D.), a running buffer of 20 mM sodium phosphate (pH 7.0), an applied voltage of 25 kV and a temperature of 40 degrees C, combined with diode array detection. Using a methanolic-aqueous extract of Epilobium angustifolium L. as an example, the possibility of using the method developed for the identification of plant acids in plant material is demonstrated. Ferulic, gallic, protocatechuic, cinnamic, caffeic, gentisic and chlorogenic acids could be identified. (C) 1998 Elsevier Science B.V.