Study On The Preparation Of Biosensor For Rhenol Detection

Phenolic compounds which belong to high-toxic compounds are considered to be very toxic to humans as well as to the environment.Therefore,determination of phenolic compounds is very important.In recent years,amperometric enzyme biosensors have received the major share of attention because of the advantages such as good selectivity, low cost,and easy automation.The main contents of this work are as follows:A tyrosinase biosensor based on Prussian Blue-modified glassy carbon electrode, combined with SiO₂ sol-gel immobilization,is constructed in a "sandwich" configuration. A new approach is developed that prepared amperometric tyrosinase biosensor for phenol detection.The optimum preparing conditions and experimental conditions of biosensor have been investigated.The response characteristics,the nature of kinetics and selectivity of tyrosinase biosensor have been studied.The results show that tyrosinase biosensor for phenol determination give the linear range of from 0 to 100μmol/L,sensitivity of 27.25 mA/μmol·L^-1,the response time of shorter than 10 s,and the detection limit of 1.06μmol/L.And it also has a better response to catechol and p-dihydroxybenzene.An amperometric electrode using glucose oxidase entrapped in SiO₂ sol-gel,based on PB-modified,has been developed for measuring of phenolic compounds.The suitable preparing conditions and experimental conditions have been described.Experiments prove that optimized conditions are the optimum potential for work of-0.15 V,the suitable phosphate buffer pH of 6.5,the most appropriate temperature is of 35℃,the optimum fixed amount of glucose oxidase of 60μg,and the most appropriate glucose concentration of 1mmol/L.The response properties,the nature of kinetics as well as selectivity of glucose oxidase biosensor have been evaluated.The testing results illustrate the glucose oxidase biosensor prepared by this method exhibits better selectivity,but its sensitivity is lower and only response to p-dihydroxybenzene.In addition,the inhibitive effect of heavy metal ions-Hg²⁺on tyrosinase biosensor has been also investigated.The experimental results show the amprometric response to biosensor is inhibited due to the existence of Hg²⁺ when the most appropriate working potential is -0.20 V and pH is 5.0.There is a linear relationship between the inhibited amprometric response and the certain concentration of Hg²⁺.The part recovery of response on the inhibited tyrosinase biosensor is possible by immersing it in a EDTA solution after 10min.