An electrochemical sensing platform based on nitrogen-doped hollow carbon spheres for sensitive and selective isoprenaline detection

Abstract

In this work, uniform and monodisperse hollow carbon spheres (HCSs) are synthesized through two different processes using polydopamine (PDA), as a carbon precursor, and silica core as a template, under the modified Stöber condition. The surface morphology of the synthesized structures is characterized by means of scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDX) and Fourier-transform infrared spectroscopy (FT-IR). In the next step, the electrochemical behavior of isoprenaline (ISPN) is investigated by using glassy carbon electrode modified with a thin film of the synthesized hollow carbon spheres. The electrochemical characterization of the modified electrodes is performed using cyclic voltammetry (CV) and linear sweep voltammetry (LSV). In comparison to bare GCE, an enhanced oxidation peak current for ISPN is observed on the surface of HCSs/GCE. Comparing two different hollow carbonic structures, the HCS(1), which shows high nitrogen contents and high surface area, is selected as the suitable modifier for the sensitive determination of ISPN. The effect of various experimental parameters such as the pH of electrolyte solution, the amount of casted HCS(1) suspension, and time and potential of the accumulation on the electrochemical response of ISPN are investigated and optimized by linear sweep voltammetry method. Under the optimum conditions, the response of the modified electrode exhibited two wide linear ranges of 0.2–2μM and 2–30μM with a low detection limit of 60nM for voltammetric determination of ISPN. Beside high sensitivity, the fabricated electrode represented excellent selectivity toward ISPN in the presence of biological interfering species such as ascorbic acid (AA) and uric acid (UA), which make it more suitable for determination of ISPN in pharmaceutical and clinical samples.