| In this paper, the feasibility of application of biosensor to determine the contamination in the complex compost system is basically reviewed. With the work we have accomplished by far, enzyme biosensor and immunosensor based on the immunochemical analysis which is used to detect the pollutant in the complex compost system were studied.Composting technology is applied to disposal of the municipal solid waste increasingly. With the enhancement of the demand of environment quality, there should be a set of detecting methods to match the correlative standard of environment protection. Due to the complexity, diversification and uncertain characteristics of the complex compost system, the commonly used analytical methods, such as spectrophotometry, gas chromatography and high performance liquid chromatography (HPLC) based on the absorbance spectra, are probably interfered by the interference of substrate turbidity and light disturbance, and the pretreatment of the samples is cumbrous and time-consuming, and the instruments are expensive and ponderous. However, biosensor is known for its superior sensitivity, stability, reusability, selectivity, portablity and other obvious advantages. The operation efficiency of compost system will be improved much if biosensor is applied to detect the pollutant in compost.First, a biosensor was developed and used to analyze the concentration of phenols in compost extracts based on the immobilization of laccase on the surface of modified magnetic core-shall (Fe3O4-SiO2) nanoparticles. Laccase does not need H2O2 as co-substrate or any other co-factors for its catalysis. It can directly catalyse the oxidation of phenols accompanied by the reduction of oxygen. Laccase was convalently immobilized by glutaraldehyde on the magnetic nanoparticles which were modified with amino groups on the surface. The obtained magnetic bio-nanoparticles were attached to the surface of carbon paste electrode with the help of a permanent magnet to respectively determine catechol and hydroquinone. The immobilization matrix provided a good microenvironment for retaining the bioactivity of laccase. The linear range for catechol and hydroquinone determination are 7.5×10-72.75×10-4 mol/L and 1×10-71.375×10-4 mol/L separately, with a detection limit of 7.5×10-7 mol/L and 1.5×10-8 mol/L, respectively. The current reaches 95% of the steady-state current within about 70 s. Catechol and hydroquinone concentration in compost extracts were determined by laccase biosensor and HPLC, the results of the two methods were approximately the same.Next, an on-line system of detection and prediction by artificial neural network (ANN) as a chemometric tool was built to determine the contamination in compost system more effectively. It was a further study based on the laccase biosensor which we have developed. ANN model is a so-called"black box"as it does not need any model structure specification, and due to the strong learning capability and adaptability of ANN, it can be applied to treat the dynamic, nonlinear and uncertain properties of the complex composting system to realize the soft-determination. The performance of the ANN model was compared with the regression model in respect to simulation accuracy, adaptability to uncertainty, etc. All the results show that the combination of amperometric enzyme sensor and artificial neural networks is a rapid, sensitive and robust method in the quantitative study of composting system. Though the ANN model we obtained is a primary model, it can pave the way for further model of more complex system.Finally, the immunochemical analysis was used to detect picloram, an environmental hormone. Picloram as a hapten was coupled with BSA through 1-Ethyl-3-(3-dimethyllaminopropyl)carbodiimide hydrochloride (EDC), obtaining an antigen with immunogenicity and reactogenicity. We injected the obtained antigen into rabbit to get immunity, and then got the antibody of picloram. The double immunodiffusion test and ELISA assay were used to identify the titer and performance of the antibody. In the future, we are ready to develop an immunosensor to determine the picloram in the compost and XiangJiang River. The antibody is immobilized on the slide glass, and then the Fluorscence (FITC) is embed into the liposome modified with the picloram-antibody. The liposome embed with FITC can be used as a signal magnifier to realize the fluorescent detecting technique.
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