پديدآورندگان :
Jalaly Shahnaz - Yazd University, Yazd , Zare Hamid R. hrzare@yazd.ac.ir Yazd University, Yazd , Shekari Zahra - Yazd University, Yazd
چكيده فارسي :
Noradrenaline (NA), is the most important catecholamine neurotransmitter in the mammalian central nervous system [1]. It can be used for treating myocardial infarction hypertension, bronchial asthma and organic heart disease. Extreme abnormalities of NA concentration levels may lead to the occurrence of many diseases, such as ganglia neuroblastoma, ganglion neuronal, paraganglioma and Parkinson disease [2]. Hence, it is very necessary to develop sensitive, selective, and reliable methods for the direct determination of trace NA [3, 4].In this research, electrochemical characteristics of an immobilized 4-(4-nitrophenylazo)catechol, NC, film on multi–wall carbon nanotubes electrodeposited whit platinum nanoparticles glassy carbon electrode (NC–Pt–NPs/MWCNT–GCE) and its role as a sensor for electrocatalytic oxidation of NA are described. The apparent charge transfer rate constant, ks, and the charge transfer coefficient, α, for the electron transfer between NC and Pt–NPs/MWCNT–GCE were calculated at pH 7.0. The NC–Pt–NPs/MWCNT–GCE exhibited catalytic activity toward the electrooxidation of NA. The obtained results indicate that NA peak potential at NC–Pt–NPs/MWCNT–GCE shifted about 200 mV to negative values as compared with bare GCE. In other words, the combination of MWCNT and Pt–NPs and immobilization of NC definitely improve the characteristics of NA oxidation. The kinetic parameters such as the electron transfer coefficient, α, and the heterogeneous rate constant, k h, for the oxidation of NA at the NC–Pt–NPs/MWCNT–GCE surface were determined using cyclic voltammetry. The diffusion coefficient of NA was determined using chronoamperometry. Differential pulse voltammetry exhibited two linear dynamic ranges of 0.4-53.9 µM and 53.9-714.3 µM and low detection limit of 0.15 µM for NA. Moreover, NC–Pt–NPs/MWCNT–GCE has been applied to determination of NA in injection solution with satisfactory results.
