A Potentionmetric H₂O₂Biosensor Based On Prussian Blue Composite Material And The Determination Of Organphosphorus Pesticide

Hydrogen peroxide(H2O2) can be widely used in manufacture and life. But ecological environment and human health can be affected thanks to its excessive concentration. Instrumental method has been utilized for detection of H2O2. Rapid detection of H2O2can’t be achieved with these methods. Nowadays, the application of biosensor technique to detect H2O2has become a hot issue because of the excellent performance. The application of biosensor to detect pesticide residue has received significant attention.Pesticide plays an important role in keeping the food production. However, the percentages of cancer disease are dramatic increased because of the residues of excessive pesticide in food. Thus, it is the urgent question must be envolved for environmental protection and food quality in determination of pesticide residues rapidly and accurately. The enzyme activity inhibition-based on organophosphorous pesticide(OP) biosensor has received attention. But the enzyme cost expensive, easy inactivate and unstable. Thus, the research of like-enzyme catalyzer has received attention.In this thesis, a novel simple and non-enzyme potentiometric H2O2sensor consistes of gold electrode modified with nano colloid gold-multi-wall carbon nanotube-chitosan(GNPs-MWCNTs-CS) and PB@Au was fabricated. Trace amounts of parathion and folimate are analyzed, according to the enzyme ALP inhibition by organophosphorus pesticide. Results show that this biosensor prepares simply, possesses high performance and rapid detection of organophosphorus pesticide residue can be achieved under non-enzyme condition. In this thesis the major contents include three sections as follows:1. A H2O2sensor based on two magnetic nanoparticles and horseradish peroxidase synergistic catalyze effectsAu@PB MNPs and Au@Fe3O4MNPs are electrodepositied on magnetic carbon paste electrode(MCPE) by applying constant potential. Then horseradish peroxidase(HRP) is immobilized on the modified electrode. Thus, a potentiometric H2O2sensor is prepared. The resulting sensor is used to detect the H2O2contents in the rain. Result shows that the resulting biosensor possesses the excellent selectivity and good stability, which has potential application.2. A potentiometric H2O2sensor based on composite material and PB@Au modified the gold disk electrode (GE) A novel potentiometric H2O2sensor consistes of gold electrode modified with nano colloid gold-multiwall carbon nanotube-chitosan(GNPs-MWCNTs-CS) and PB@Au was fabricated. Trace H2O2has detected by using synergistic effects of GNPs, MWCNTs and CS, the enzyme-like catalytic activity of PB@Au which catalyze H2O2and oxidate. The function of o-phenylenediamine (OPD) is researched in the absence of OPD and the prescence of OPD. Results show that the H2O2sensor shows excellent performance, selectivity and good stability, which can be used in trace detection of H2O2under non-enzyme condition.3. The detection of organophosphorus pesticide residue.The H2O2producted in the system of catalyze3-IP by ALP is detected, trace parathion and folimate are analyzed based on the catalytic activity of ALP is drastically inhibited, a detection limit is10-6mol/L and the response time are50s and70s, accordingly. As a result, the method realizes the detection of trace organophosphate pesticides residue.Actual samples resluts for each kg of parathion residues in pakchoi is0.21mg, each kg of folimate residues in pakchoi is8.5mg, recovery is berween70%and90%.