The Amperometric Determination of Indole-3-acetic Acid Based on CeCl3-DHP Film Modified Gold Electrode

An amperometric sensor for the determination of indole-3-acetic acid (IAA) based on the CeCl3-DHP film modified gold electrode was developed. CeCl3 was dissolved into water in the presence of dihexadecyl hydrogen phosphate (DHP). The IAA sensor was prepared via evaporating solvent of the CeCl3-DHP dispersion on the gold electrode surface. The amperometric response of IAA on the CeCl3-DHP film modified gold electrode was investigated. The experimental results indicate that the passivation of the electrode due to the adsorption of the oxidation product of IAA decreases significantly at the CeCl3-DHP film modified gold electrode, in contrast to that at the bare and the DHP modified gold electrode. The experimental parameters were optimized and an electrochemical method for the determination of IAA was established. The oxidation peak current is linearly with the concentration of IAA from 1 x 10(-7) to 2 x 10(-5) mol l(-1) and the detection limit is 3 x 10(-8) mol l(-1). The relative standard deviation of eight measurements is 3.2% for 5 x 10(-7) mol l(-1) IAA. The IAA in plant leaves were extracted and determined by the IAA sensor.