A novel sensor based on LaPO4 nanowires modified electrode for sensitive simultaneous determination of dopamine and uric acid

LaPO4 nanowires were synthesized by a simple hydrothermal method and characterized using transmission electron microscope (TEM), energy dispersive X-ray spectroscopy (EDS), and scanning electron microscopy (SEM). A novel electrochemical sensor has been fabricated by use of a carbon paste electrode (CPE) coated with the prepared LaPO4 nanowires. Electrochemical characterization of the sensor was investigated by electrochemical impedance spectroscopy (EIS), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The nanowires-LaPO4 showed excellent electrocatalytic activity toward the oxidation of dopamine (DA) and uric acid (UA) simultaneously. Moreover, the sensor exhibits good selectivity toward simultaneous determination of DA and UA. By using DPV method, low detection limits of 1.3 × 10−7 mol L−1 and 9.0 × 10−7 mol L−1 for DA and UA were obtained, with the linear calibration curves over the concentration range 4.00 × 10−7–1.14 × 10−5 mol L−1 and 2.70 × 10−6–2.48 × 10−5 mol L−1, respectively. In addition, the sensor was successfully applied for the determination of analytes in injection samples using the standard adding method with satisfactory results.

The DPVs of DA with different concentrations at the nanowires-LaPO4/CPE.Figure optionsDownload as PowerPoint slideHighlights
► LaPO4 nanowires were successfully synthesized by a simple hydrothermal treatment and characterized by TEM and EDS.
► A novel electrochemical sensor was fabricated by use of a carbon paste electrode coated with nanowires-LaPO4.
► This sensor exhibits improved sensitivity and large linear range and the anodic peak current of DA has enhanced about 4-fold.
► It was applied to detect simultaneously DA and UA and exhibited strong catalytic activity.
► The sensor was successfully used for the determination of DA in pharmaceutical samples.