| Indole-3-acetic acid (IAA) has a great significance in the regulation of plants'growth and development. The content of IAA in plants is very low, which is easily decomposed by heat, light or oxygen. Hence, both agricultural production and the research of IAA call for an efficient, convenient and precise measurement method for the detection of IAA in plants. In this paper, two electrochemical biosensors were developed for the detection of IAA content in plants, main results are as follows:1. Application of enzyme sensor:An electrochemical amperometric enzyme sensor based on poly-thionine modified platinum electrode for the detection of IAA was proposed in this paper. The new sensor was developed mainly according to the oxidation reaction of IAA catalyzed by horseradish peroxidase (HRP). Since this oxidation reaction is substantially the electron transfer process, the current changes when electron transfer reaction occurs on the surface of electrode. Thus, it can provide a general electrochemical method for the direct detection of IAA. The results indicated that this enzyme sensor had satisfactory linearity with the content of IAA in the range of lng·mL-1-30ng-mL"1 with a detection limit of 0.1ng·mL-1.2. Application of Immunosensor:A novel immunosensor for indole-3-acetic acid detection based on immobilizing antibody by yeast cell was proposed in this paper. The proposed sensor was mainly according to the immunoreaction of IAA and anti-IAA antibody. The new method of immobilization based on yeast cell can enhance the detecting limit and sensitivity observably. The results indicated that this immunosensor had satisfactory linearity with the content of IAA in the range of lng·mL-1-125ng·mL-1 with a detection limit of 0.05ng·mL-1. It is a new technology for the rapid determination for the IAA. |
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