Leaf analysis for abscisic, phaseic and 3-indolylacetic acids by high-performance liquid chromatography

Abstract High-performance liquid chromatography (HLPC) is described for the purification and analysis of abscisic acid (AbA), phaseic acid (PA) and 3-indolylacetic acid (IAA) extracted from Sorghum bicolor leaves . The method is rapid, suitable for automation and capable of accommodating large numbers of samples. Detection limits are less than 1 ng for each hormone. Recovery efficiency is 75% for AbA and PA and 64% for IAA. After initial extraction and partition, AbA, PA and IAA were purified together as ammonium salts (ion pairs) on polyvinylpyrrolidone. This was followed by further purification and separation of the three hormones on preparative C 18 reversed-phase HPLC (5-μm spherical particles). Analysis of AbA and PA was by absorption phase silica HPLC (5-μm spherical particles) with detection by UV absorption. Analysis of IAA was by C 18 reversed-phase HPLC (5-μm spherical particles), with fluorescence detection.