Highly sensitive and disposable electrochemical nano sensor for simultaneous analysis of caffeic acid and uric acid based on halloysite nanotubes and magnetite nanoparticles

Simultaneous quantitative analysis of caffeic acid (CAFA) and uric acid (UA) in biological samples was carried out using a pencil graphite electrode (PGE) coated with a mixture of halloysite (a clay mineral) nanotubes (HNTs) and magnetite (Fe3O4) nanoparticles. Surface morphology and electrochemical characterization of the sensor were investigated by field emission scanning electron microscopy (FE-SEM), Energy dispersive X-ray analysis (EDX), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS). The sensor prepared has an effective surface area 1.75 times larger than that of the corresponding bare PGE electrode. Oxidation peak currents for CAFA and UA obtained by the sensor increased by 1.4 and 2.0 times, respectively, compared to the values found with bare PGE. Under the optimal conditions, linear working ranges for CAFA and UA were found in the ranges (0.027-70.0 mu M) and (0.009-70.0 mu M), respectively. The respective detection limits were 0.008 mu M and 0.003 mu M. The sensor developed was shown to be applicable to quantifying the analytes simultaneously in human serum and urine.

Automated summary

A pencil graphite electrode coated with halloysite nanotubes and magnetite nanoparticles was used for simultaneous quantitative analysis of caffeic acid and uric acid in biological samples. The sensor showed an increased effective surface area and improved oxidation peak currents for both analytes compared to a bare electrode.