Electrochemical Determination of Isoproterenol at Silver (I) Complex-Graphene-Modified Glassy Carbon Electrode

Isoproterenol (ISO), is b-adrenergic agonist and synthetic catecholamine that is structurallyrelated to epinephrine but acts almost exclusively on beta receptors. Its primary use is forbradycardia or heart block. By activating β1 adrenergic receptor in the heart, it induces positivechronotropic, dromotropic, and inotropic effects. It can be used as an inhaled aerosol to treatasthma, although this is currently a rare treatment. Although it activates all beta adrenergicreceptors, it works in a similar fashion to selective β2 adrenergic agonists, e.g. salbutamol, byrelaxing the airways to increase airflow. Used with caution, it can also be used to treat torsadesde pointes by acquired defect, in conjunction with overdrive pacing and magnesium sulfate.The excessive amount of isoproterenol makes some side effects on human health such aspalpitations, angina, Adam-Stokes syndrome, pulmonary edema, hypertension, hypotension,diaphoresis, mild tremors [1]. So, concentration determination of isoproterenol is very essentialto control its dosage. Various methods have been developed for the determination ofisoproterenol. Among them electrochemical method has drawn much attention by offeringadvantages including simplicity, good stability and low costs. Unfortunately, isoproterenol,with a large overpotential for oxidization at ordinary electrodes, is not a suitable analyte forthese methods. One promising approach for minimizing overvoltage effects is the use ofchemically modified electrodes [2]. Graphene is a two-dimensional carbon plane with oneatomicthickness. Since the paper on the freestanding graphene was published, the structure andproperty of graphene have attracted great attention owing to its particular quantum Hall effect,sensitivity, mechanical hardness, electrical conductivity and so on. These properties suggestwide applications, including field effect transistors, adsorbents, lithium-ion batteries andsensors [3]. In contrast, Ag(I) complex possesses the best catalytic activity and is still the mostefficient catalyst for many reactions. Consequently, researchers are interested in the dispersionof Ag(I) complex on graphene. The electrochemical determination of isoproterenol using silver(I)-graphene-modified glassy carbon electrode (GME) was investigated by cyclic voltammetry(scheme 1, Ag(I) complex). The results showed that the GME exhibited excellentelectrochemical activity towards isoproterenol. The plot of catalytic current versusisoproterenol concentration showed two linear segments in the concentration ranges 2.1×10-7–1.0×10-5 and 1.0×10-5–1.0×10-4 M and a detection limit of 6.4×10−8 M. This method is ofsimplicity, rapidity, and high sensitivity and provides a practicable solution for the selectivedetermination of isoproterenol. The method has been successfully applied to isoproterenolsample analysis.

Keywords:

Isoproterenol , Silver (I) complex , Graphene , glassy carbon electrode