The Rapid Detection Of Nematocides Based On Quartz Crystal Microbalance

Plant nematodes has become the world one of the important diseases in agricultural production, causing serious economic losses each year. So far, the control of plant nematodes disease prevention and control of chemical pesticides is still the main means, but the pesticide residues not only affects the health of people and livestock, but also seriously damage the ecological environment. Piezoelectric biosensor is a new pesticide residue detection methods, is sensitive, specific, real-time micro-and fast that detection of food and the advantages of pesticide residues in agricultural products, thus becoming a new hot spot and direction of research. However, the piezoelectric biosensor are still exist re-use rate is low for immobilized enzyme, fixed amount of enzyme is low, poor stability, not easy to achieve multi-component detection and non-specific adsorption of signal interference and other shortcomings. In this experiment, using quartz crystal microbalance sensitivity to quality,studies for the detection of nematicide, and fixed new methods to improve the fixed amount of acetylcholinesterase and stability. Further research and development for rapid, sensitive, highly specific and can detect a new type of pesticide residues in AChE piezoelectric biosensor provides a theoretical basis.Experiment with poly diallyl dimethyl amine hydrochloride (PDDA) and polystyrene sulfonate (PSS) for the assembly of materials, quartz crystal microbalance electrodes on the layer self-assembly. Test in the outermost layer of self-assembled films assembled multi-walled carbon nanotubes with carboxylic group (MWNTs-COOH) carboxyl after the multi-walled carbon nanotubes on the surface fixation technology of acetylcholinesterase. Layers of PDDA and PSS on the concentration of self-assembly, multi-walled carbon nanotubes with carboxylic group concentration of the buffer, pH and concentration of acetylcholinesterase were optimized. Selected by the study of poly diallyl dimethyl amine hydrochloride (PDDA) and polystyrene sulfonate (PSS) of the optimum concentration of 1 mg/mL; concentration of carboxyl carbon nanotubes was 0.3 mg/mL; acetylcholinesterase best fixed conditions was 0.1mg/mL; buffer solution pH 7.0. Confirmed the stability of acetylcholinesterase electrodes, clear the 4°C conditions save 7d at least. Proved that the introduction of carbon nanotubes can greatly enhance a fixed amount of acetylcholinesterase. Quartz crystal microbalance (QCM) was used to detect chlorpyrifos and phoxim nematicide standard, and draw a standard curve of chlorpyrifos and phoxim for quantitative analysis of real samples.Application of layer self-assembly immobilized enzyme technology, establishment of the quartz crystal microbalance (QCM) assay nematicide applications were detected. Grow pot of radish (Raphanus) in greenhouse, post-emergence spraying pesticide chlorpyrifos or phoxim, 4d and 8d after treatment with the current international standard by gas chromatography (GC) detection of residues of chlorpyrifos and the phoxim comparison, QCM detection limits up to 0.1 ng/mL, and the GC method are basically the same results. Show that the test preparation piezoelectric biosensor can effectively detect pesticide residues.