Abstract
Electroactive adducts, comprising 3α,6α–mannan attached to the six-valent osmium complex with N,N,N´,N?-tetramethylenediamine (simply denoted, Man- Os (VI) tmen) was immobilized on the surface of graphite electrodes via a simple adsorption route and then covered with poly(sodium-4 styrene sulfonate) (PSS). Cyclic voltammograms of modified electrodes GE/Man-Os (VI) tmen showed a clear and well-resolved anodic peak for 1 mM of dopamine DA, ascorbate AA, and urate UA at the potential range of -50 to +350 mV vs. Ag|AgCl|(KClsat.) the sensor GE/Man-Os (VI) tmen/PSS was successfully used for sensitive and selective determination of DA in the presence of an excess concentration of AA and UA, 5 mM and 0.5 mM respectively, using differential pulse voltammetry. Under optimized conditions, the peak current densities were linear from 0.1 nM to 20 μM of DA with a sensitivity of 358 μA μΜ-1 and a detection limit LOD (3SD/slope) of 2.8 nM. Further modifying of the sensor using multiwall carbon nanotubes decorated with gold nanoparticles (AuNPs-MWCNTs) led to substantial improvement in its analytical characteristics. The linear response of the electrode modified GE/ AuNPs-MWCNT/Man-Os (VI) tmen to DA was spanned from 1 pM to 40 μM with a high sensitivity of 624.49 μA μΜ-1 and a LOD (3SD/slope) of 0.17 pM.
Highlights
Today, awareness on the levels of the important species in the body is one of the main necessities for everyone in order to control health and increase quality of life
The formal potential E°' was found to be 184 mV vs. Ag|AgCl| (KClsat.). This observation is in consensus with results reported by others [60]. (Figures 2A and 2B) demonstrate the cyclic voltammetry (CV) of the Man-Os (VI) tmen modified graphite electrode in the absence (b: violet color) and presence (d: red color) of 1 mM DA, respectively
This study showed that the peak current of DA oxidation at the (d) graphite electrode (GE)/AuNPs-MWCNTs/Man-Os (VI) tmen, was higher than those observed at the other three electrodes
Summary
Awareness on the levels of the important species in the body is one of the main necessities for everyone in order to control health and increase quality of life. During past decades and later on, many different types of modifiers have been used to build up a desired chemical functionality on the electrode surface, including conducting and non-conducting polymers, ionic liquids, redox organic and inorganic mediators [4,5,6,7,8,9,10,11,12,13]. On the other hand carbon nanotubes have been interesting as electrode materials according to their unique physicochemical properties and high surface area It seems that one can achieve much better catalytic effects by combining metal nanoparticles and carbon nanotubes compared to these materials alone [32]. These hybrid nanomaterials have received much more attention according to their interesting structural, electrochemical,
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
