Studies On The Fabrication Of Nano-composite ZrO2/Au Film And Its Application For Voltammetric Detection Of Organophosphate Pesticides

Extensive usage of pesticides in agriculture, which lead to accumulation of pesticide residue in soil, water and food, has imposed a serious risk to human health and environment worldwide. In fact, most (70%) pesticides in the market are organophosphates, which have high toxic effect on the nerve of human beings or animals. So many efforts have been made to develop sensitive, convenient and effective methods for organophosphate pesticides (OPs) analysis in environmental samples.As electrochemically active compounds, OPs are very suitable for electrochemical detection. Compared with the instrumental analysis techniques or test-kit methods, electrochemical approach can provide electronic signals directly with a lower cost and reduced analysis time, and electrochemical systems can be easily miniaturized and integrated. However, in the recent reports, the complicated fabrication process, the short lifetime or the poor anti-interference on its surface of the working electrodes prohibit wide usage of these electrochemical sensors in real practice.Based on the high surface area of nanoparticles and its selective affinity for phosphate groups of zirconia, this paper reports on the fabrication of ZrO₂/Au nano-composite electroless coating film electrode on alumina substrate and its application for OPs voltammetric detection. The fabrication and performance of the ZrO₂/Au film electrode are discussed and optimized.The paper consists of five chapters. In chapter 1, studies on OPs detection, especially on its electrochemical detection, are classified and summarized. Then the existing problems and its development in voltammetric detection of OPs are analyzed. Based on which, the objectives and the applications program of the present study in this paper are offered.In chapter 2, synthesis of zirconia nano particles used to fabricate the nano-composite ZrO₂/Au film electrode through a modified sol-gel technique is elaborated. Factors influencing the size of nano zirconia are discussed and optimized. In chapter 3, fabrication of nano-composite ZrO₂/Au film electrode used to voltammetric detection of OPs is described. Factors influencing nano-composite electroless plating and its basic electrochemical performance are discussed and optimized.In chapter 4, voltammetric detection of OPs with nano-composite ZrO₂/Au film electrode as the working electrode is discussed. The sensitivity, long-term stability, interference studies prove the good performance of the nano-composite ZrO₂/Au film electrode for OPs tests.In chapter 5, the fabrication process of the nano-composite ZrO₂/Au film electrode as well as its application in voltammetric detection of OPs is summarized. And the prospect of its development is described.