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

Isoproterenol (ISO), is b-adrenergic agonist and synthetic catecholamine that is structurally related to epinephrine but acts almost exclusively on beta receptors. Its primary use is for bradycardia or heart block. By activating β1 adrenergic receptor in the heart, it induces positive chronotropic, dromotropic, and inotropic effects. It can be used as an inhaled aerosol to treat asthma, although this is currently a rare treatment. Although it activates all beta adrenergic receptors, it works in a similar fashion to selective β2 adrenergic agonists, e.g. salbutamol, by relaxing the airways to increase airflow. Used with caution, it can also be used to treat torsades de 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 as palpitations, angina, Adam-Stokes syndrome, pulmonary edema, hypertension, hypotension, diaphoresis, mild tremors [1]. So, concentration determination of isoproterenol is very essential to control its dosage. Various methods have been developed for the determination of isoproterenol. Among them electrochemical method has drawn much attention by offering advantages including simplicity, good stability and low costs. Unfortunately, isoproterenol, with a large overpotential for oxidization at ordinary electrodes, is not a suitable analyte for these methods. One promising approach for minimizing overvoltage effects is the use of chemically modified electrodes [2]. Graphene is a two-dimensional carbon plane with oneatomic thickness. Since the paper on the freestanding graphene was published, the structure and property of graphene have attracted great attention owing to its particular quantum Hall effect, sensitivity, mechanical hardness, electrical conductivity and so on. These properties suggest wide applications, including field effect transistors, adsorbents, lithium-ion batteries and sensors [3]. In contrast, Ag(I) complex possesses the best catalytic activity and is still the most efficient catalyst for many reactions. Consequently, researchers are interested in the dispersion of Ag(I) complex on graphene. The electrochemical determination of isoproterenol using silver 32 (I)-graphene-modified glassy carbon electrode (GME) was investigated by cyclic voltammetry (scheme 1, Ag(I) complex). The results showed that the GME exhibited excellent electrochemical activity towards isoproterenol. The plot of catalytic current versus isoproterenol 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 of simplicity, rapidity, and high sensitivity and provides a practicable solution for the selective determination of isoproterenol. The method has been successfully applied to isoproterenol sample analysis. Scheme 1