Auxin Analysis

Plant hormones are present and active in minor concentrations in plant tissue. To allow quantification in a restricted amount of material, i.e., protoplasts, chloroplasts, seedlings, seeds, buds, or apical root- and stem regions, a sensitive analytical technique is a prerequisite. During the last two decades, procedures for phytohormone analysis as well as the available hardware have improved substantially. Fluorimetry is widely used for the analysis of indole-3-acetic acid (IAA) because it is more specific and therefore more sensitive than ultraviolet detection (for a review see ref. 1 ). Good detection limits for derivatized IAA are obtained in Electron Impact (EI⁺ ) (2 ,3 ) or negative ion chemical ionization (NICI) GC-MS (4 ,5 ).