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Development of paper type tyrosinase biosensor

Şenyurt, Özge
Phenolic compounds are the chemicals which are used by many different industries and as a result of this spread to the environment. These compounds can be absorbed easily through the human and animal skin and through the mucosal membrane, mix in to the blood circulation and thus create a toxic effect on several tissue and organs including, liver, lung and kidneys. For this reason, determination of phenolic compounds emitted to environment is a very important issue. In fact, there are standard methods for the determination of these compounds like HPLC, Spectrophotometric and calorimetric methods however, these are time consuming methods and requires to be expertise. On the other hand, there are also different types of biosensors developed for the phenolic compound detection. In this study, a new, disposable, cheap and convenient tyrosinase biosensor was developed for the phenolic compound detection. By means of absorption method, the enzyme tyrosinase and the chromophore MBTH were immobilized on the support material and as a model substrate L- dopa was used. As a result of optimization studies 1mg/ml tyrosinase concentration and 1.5mM MBTH concentration were determined for using in biosensor construction. Detection limit of l-dopa, model substrate, found as 0,064 mM and for other phenolic compounds, 4-chlorophenol, catechol, m-cresol and p-cresol, detection limit was obtained 0.032 mM, 0.032 mM, 0.128 mM, 0.128 mM, respectively. In addition, we found that the biosensor response was not affected by pH changes ranging from 3 to 11. The stability of biosensor which is one of the important parameter for commercialization was not change through 70 days at room temperature and 4°C when compared to at the beginning response.