| With the rapid development of industrialization, urbanization and the continuous improvement ofpeople’s living standard, environmental pollution problems increased seriously, which brought greatdangerous for human life and health. Therefore, human beings gradually realized the importance ofenvironmental protection. Environmental protection had become one of the focus problems around theworld. In order to manage and protect environment, our country had a series of policies and regulations tobuilding a resource-conserving and environment-friendly society, and had promoted environmentalprotection and economic development to national strategic height. Environmental pollution control was animportant content of environmental protection, and analysis and monitoring of pollutants was an essentialmeans for pollution control. So, development sensitive and accurate methods for pollution analysis werevery important.Phenolic pollutants were a kind of common environmental pollutants, which were mainly derivedfrom industrial wastewater. This article mainly discussed the application of laccase electrochemicalbiosensor for detection catechol and hydroquinone, and studied the effective fixed method of laccase andthe mechanism of laccase electrochemical biosensor for detection catechol and hydroquinone. Thosebiosensors were applied to detect catechol and hydroquinone successfully. Specific works were as follows: 1. Preparation of a New Laccase Biosensor Based on Bimetallic Pt/Au Particles and Chitosan/silicaSol-gel Bybrid Films for Determination of CatecholA novel laccase (Lac) biosensor was fabricated successfully by means of entrapping Lac in bimetallicPt/Au particles and chitosan/silica (CS-SiO2) sol-gel hybrid films, and was applied to determine catecholconcentration. The experiments showed that the biosensor can electrocatalyze the reduction of catechol,and the peak current of catechol increased significantly with its concentration in the range of8.0×10-7~1.0×10-4mol/L (r=0.9993) with a detection limit of7.9×10-8mol/L by cyclic voltammetric response. Thebiosensor exhibited good sensitivity and stability, with broad linear range for potential applications.2. A Novel Laccase Biosensor Based on ZnO Sol-gel for Determination of CatecholIn this work, a laccase biosensor was prepared by entrapping Lac in ZnO sol-gel with chitosan (CS) asa matrix, and was used to detect the concentration of catechol. ZnO nanoparticles were characterized byX-ray diffraction (XRD) and atomic force microscopy (AFM). The conductivity of CS/ZnO/GC film wasinvestigated by AC impedance. Experiments showed that the biosensor can electrocatalyze catechol and thelinear range was from1.0×10-6to1.0×10-4mol/L (r=0.9993) with the detection limit of2.9×10-7mol/L.The proposed biosensor exhibited good stability, reproducibility and certain anti-interference ability.3. A Laccase Biosensor Based on Graphene-Chitosan Composite Film for Determination ofHydroquinoneA novel laccase biosensor was obtained by means of entrapping laccase in graphene–chitosancomposite materials. Graphene–chitosan composite had good conductivity, high stability and goodbiocompatibility. Laccase can be firmly embedded into the composite without the aid of other cross-linkingreagents. Morphology and electrical conductivity of graphene-chitosan film were measured by scanning electron microscope (SEM) and electrochemical impedance spectra (EIS) techniques. This biosensorcatalyzed the oxidation of hydroquinone to p-quinone, and p-quinone electrochemical reduced back tohydroquinone. This biosensor response to hydroquinone in the linear range of2.0×10-6~1.0×10-4mol/L(r=0.9975) with a detection limit of2.6×10-7mol/L. The response time of the biosensor to reach95%steady-state current was less than10s. Moreover, the biosensor exhibited good stability, reproducibility andcertain anti-interference ability.4. Simultaneous Determination of Catechol and Hydroquinone Using a Self-assembled LaccaseBiosensor Based on NanofilmIn this work, a laccase biosensor was fabricated by means of self-assembled technique to immobilizeLac on the surface of glassy carbon (GC) electrode modified with multi-walled carbon nanotubes(MWCNTs). The electrochemical behavior of this modified electrode was studied through cyclicvoltammetry. The experiments showed that the biosensor can determine both catechol and hydroquinone.And the oxidation peak current of catechol and hydroquinone increased significantly with theirconcentrations in the range from2.0×10-6to1.0×10-3mol/L (r=0.9986) and from2.0×10-6to1.0×10-3mol/L(r=0.9987), respectively, with the detection limit of2.0×10-6mol/L and6.0×10-7mol/L, respectively. Theresponse time of the modified electrode was less than10s. Moreover, the biosensor exhibited good stabilityand reproducibility with potential applications. 5. Preparation of Poly-(p-aminobenzoic acid)/Multiwall Carbon Nanotubes Composite FilmModified Glassy Carbon Electrode and Application to Detect Catechol and HydroquinoneSimultaneouslyThe electrochemical reaction of catechol and hydroquinone was investigated at poly-(p-aminobenzoicacid)(p-ABA)/multiwall carbon nanotubes (MWCNTs) composite film modified GC electrode via cyclicvoltammetry. Under optimized conditions, the oxidation current of cathchol and hydroquinone had beenenhanced linearly with the concentration in the range of1.0×10-5~1.0×10-3mol/L (r=0.9979) and1.0×10-5~1.0×10-3mol/L (r=0.9948), with the detection limit of catechol and hydroquinone4.0×10-6mol/Land2.7×10-6mol/L, respectively. |
