Design of a multiwalled carbon nanotube–Nafion–cysteamine modified tyrosinase biosensor and its adaptation of dopamine determination

In this work, a multiwalled carbon nanotube (MWCNT)–Nafion–cysteamine (CA) modified tyrosinase biosensor brings a new and original perspective to biosensor technology intended for the development of dopamine determination. Dopamine measurements were done at 0.2V with the amperometric method by the developed biosensor system. In addition, in this study dopamine determination was carried out by using the differential pulse voltammetry method between potentials of 0.4 and −0.15V. In the optimization studies of the biosensor, some parameters such as optimal pH, optimal temperature, optimal enzyme amount, and effect of MWCNT concentration were investigated. Afterward, in the characterization studies, some parameters such as linearity and reproducibility were determined. In the reproducibility experiment, an average value of 1.026μM, a standard deviation of ±0.03975, and a coefficient of variation of 3.8% were determined for a 1-μM dopamine concentration (n=15). Determination of dopamine was carried out in drug samples by the developed biosensor.