Research Of Electrochemical Sensors For Phenol Pulltions Based On Nano Material And Its Applications In Environmental Monitoring

Phenolic compounds possess very strong toxicity to human body, which alsohave been widely applied in many fields such as industrial production, medicine,health and so on. So it is essential to establish rapid, sensitive, and simply methods formonitoring of this kind of organic compounds. Electrochemical sensors not onlypossess above-mentioned advantages, but also possess the characteristic of goodselectivity and easy fabrication. Therefore, it has become a research hotspot ofenvironmental monitoring field internationally to develop electrochemical sensors forrapid determination of phenolic pollutants.In this paper, the electrochemical sensors were fabricated used to detect phenoliccompounds according to the catalytic principle of four kinds of materials (Au particles,grapheme, manganese dioxide particles, and titania nanotube arrays). The sensorswere used for quantitative detection of phenolic compounds. The performances of thesensors were studied. The main work and results are as follows:1. According to the principle of corprecipitation manganese dioxide particleswere prepared. By electrodeposition MnO2particles and gold particles were modifiedon the surface of a glassy carbon electrode (GCE) in turn and the electrochemicalsensor (Au/MnO2/GCE) for catechol was prepared. The electrochemical behaviour ofcatechol at Au/MnO2/GCE was studied by cyclic voltammetry, and the experimentalconditions for preparation of the sensor were optimized. The sensor was used to detectthe content of catechol in samples. The oxidation peak current of catechol increasedlinearly with the concentration of catechol over the range of1.0~1000μ mol/L(correlation coefficient equal to0.9932) with a detection limit of1μ mol/L.2. Suspension of grapheme oxide (GO) and MnO2particles was prepared. Thesuspension was modified onto the surface of a GCE by dip coating method toprepared a sensor of GO-MnO2/GCE. The difference of oxidation peak potentials ofbetween catechol and hydroquinone was103mV. Therefore, it is possible todetermine catechol and hydroquinone simultaneously.The oxidation peak current of catechol increased linearly with the concentrationof catechol over the range of1.0~300μ mol/L with a detection limit of1.0μ mol/L(correlation coefficient equal to0.9996). The oxidation peak current of hydroquinoneincreased linearly with the concentration of hydroquinone over the range of1.0~70μmol/L with a detection limit of1.0μ mol/L (correlation coefficient equal to0.9907).3. Constant voltage method was used to oxidized electrochemically a piece oftitanium foil to prepare titania nanotube arrays. Gold particles was modified on TiO2 nanotube arrays by electrodeposition to prepare an electrochemical sensor ofAu/TiO2NTs/Ti. The sensor was used for the detection of catechol and hydroquinone.The difference of oxidation peak potentials of between catechol and hydroquinonewas103mV. Therefore, the sensor can be used to determine the two kinds phenolssimultaneously.The oxidation peak current of catechol or hydroquinone increased linearly withthe concentration of catechol or hydroquinone over the range of1.0~200μ mol/Lwith a detection limit of1.0μ mol/L.