Effect of La doping level on structural and sensing properties of LZO/RGO nanohybrid: Highly selective sensing platform for isoprenaline determinations in the presence of ascorbic acid, uric acid and folic acid

Abstract

An electrochemical sensor using 3% lanthanum doped zinc oxide with reduced graphene oxide (3% LZO/RGO) nonohybrid was developed for the selective and sensitive determination of isoprenaline. The LZO (La=0–5%) was synthesized by low temperature hydrothermal method. The structural and morphological changes were characterized by a variety of analytical and spectroscopy techniques, viz. X-Ray Diffraction, Fourier Transform Infrared Spectrum, X-ray Photoelectron Spectroscopy and Field Emission Scanning Electron Microscopy. Electrochemical characterization was evaluated by Electrochemical Impedance spectroscopy (EIS), Cyclic Voltammetry (CV) and Differential Pulse Voltammetry (DPV). The 3% LZO/RGO nanohybrid displayed the highest electrocatalytic activity towards isoprenaline detection. Under optimal circumstances, the present sensor showed a wide linear range (0.01 ̶ 700μM) with a detection limit of 7.23nM (at S/N=3). The sensitivity was calculated as 0.49μAμM−1cm−2. Moreover, the modified electrode offers excellent selectivity, because it can effectively avoid the interference of ascorbic acid, uric acid and folic acid even in the higher concentration. Thus, the reported sensor exhibits accurate determination of isoprenaline (in the presence of ascorbic acid, uric acid & folic acid) and possesses a good real-time application with human blood serum and urine samples and gives a satisfactory recovery.