Amperometric Detection of Isoprenaline Based on Glassy Carbon Electrode Modified by Iridium Oxide Nanoparticles

A simple and sensitive electrochemical sensor by using a glassy carbon electrode modified by iridium oxide nanoparticles (GCE/IrOxNPs) was constructed and utilized to determine isoprenaline (IP). This sensor was used successfully for IP determination in human urine samples. IrOxNPs are grown on a GCE by electrodepositing method. Various experimental parameters influencing the electrochemical behavior of the modified electrode were optimized by varying the scan rates and pH. Compared with a bare GCE, the GCE/IrOxNPs exhibits a distinct shift of the oxidation potential of IP in the cathodic direction and a marked enhancement of the current response. The results showed that GCE/IrOxNPs exhibited excellent electrochemical activity towards IP in pHy7.0 phosphate buffer solution (PBS). The detection limit, sensitivity and catalytic rate constant (k(cat)) of the modified electrode toward IP were 90 nmol L-(1), 17.3 nA mu mol-(1) L and 1.6 x 10(4) mol-(1) L s-(1), respectively, at linear concentration rang up to 2500 mu mol L-(1). The modified electrode displayed linear responses to IP in amperometry assays in real urine, with a detection limit of 120 nmol L-(1).