A renewable amperometric immunosensor for phytohormone β-indole acetic acid assay

A rapid, convenient and accurate method using a sol-gel-alginate-carbon composite electrode (SACE) is described for the determination of p-indole acetic acid (IAA) in plant samples. The determination is based on an enzyme-linked competitive immunoreaction between free IAA and IAA labeled with HRP to bind on the anti-IAA IgG immobilized on the SACE surface. The response signal expressed as percentage current reduction (CR%, y) is linearly related to the logarithm of the concentration of lAA (x) in range of 5-500 mug ml(-1) with a regression equation of the form y = 37.80 x -22.47 and correlation coefficient of 0.9922. The immunosensor was used to determine the lAA content in the hybrid rice grain samples taken in the growing period. (C) 2003 Published by Elsevier B.V.