Determination of indole-3-acetic acid and indole-3-acetylaspartic acid in pea plant with capillary electrophoresis and fluorescence detection

Abstract

A method for the simultaneous separation and determination of indole-3-acetic acid (IAA) and its primary metabolite, indole-3-acetylaspartic acid (IAAsp), in an extract from pea ( Pisum sativum), is described. The technique used is capillary electrophoresis with fluorescence detection, the finally selected analytical parameters being: buffer 30 m M acetate, pH 4.5, injection volume 26 nl, high voltage 30 kV and excitation and emission wavelengths of 254 and 360 nm, respectively. The detection limits obtained were 18 n M (0.39 fmol) for IAA and 28 n M (0.73 fmol) for IAAsp. Sample preparation procedures have also been examined. The amounts of IAA and IAAsp in shoot apices of pea were determined to 1.9·10 −10 and 1.1·10 −10 mol/g fresh mass, respectively, corresponding to 33 ng/g fresh mass for both, using indole-3-butyric acid as an internal standard.