A simplified method for the quantitative determination of indoleacetic acid by high performance liquid chromatography with a fluorometric detector

Quantitative analysis of endogenous IAA contents of radish plant extracts by high performance liquid chromatography with a fluorometric detector was refined by using a C-18 SEP-PAK cartridge for the purification procedure and indolepropionic acid as the internal standard. The C-18 SEP-PAK cartridge efficiently purified the IAA from the acidic ether-soluble fraction of the plant extracts when the pH of the fraction injected into the cartridge was kept under 3.5. Both of the recovery rates for IAA and indolepropionic acid were over 90% for the extraction and purification procedure. The endogenous IAA content in green radish seedlings, corrected by internal standard methods with indolepropionic acid, was 20.2 ng/g fr wt. This was in good agreement with the value corrected with radiolabeled 14C-IAA, 20.8 ng/g fr wt.