Graphite-polyurethane composite electrode modified with nickel(II) nanoparticles submitted to electrochemical pretreatment in basic medium for the determination of atenolol

Abstract

A new approach for the determination of atenolol (ATN) at a graphite polyurethane composite electrode (GPUE) modified with electrodeposited nickel(II) nanoparticles electrochemically pretreated in alkaline medium (GPUE-NiNP) is reported. The electrodeposition of NiNP on the GPUE surface was performed by 5 scans in cyclic voltammetry between 0.0 to −1.5 V (vs. SCE) and scan rate of 20 mV s−1 in a 0.05 mol L−1 NiSO4 and 0.32 mol L−1 H3BO3 solution at pH 5. After deposition, the GPUE-NiNP was submitted to an electrochemical pretreatment in 0.50 mol L−1 NaOH by cyclic voltammetry at 100 mV s−1. The best results were obtained after 50 cycles at 100 mV s−1. Quantitative measurements at GPUE-NiNP were performed using differential pulse voltammetry (DPV) in pH 11 universal buffer. Atenolol promotes a decrease in the nickel oxide signals probably due to a complexation of the analyte with free Ni2+ in solution. Thus, the analyte was quantified by the signal suppression and an analytical curve was obtained at the GPUE-NiNP using the optimized conditions for 1.0 to 100 x 10−8 mol L−1 atenolol between 1.0 and 0.0 V (vs. SCE) with a linear range between 2.0 x 10−8 and 1.0 x 10−7 mol L−1 and a limit of detection of 3.47 x 10−9 mol L−1 with R = 0.9995 for GPUE-NiNP. The procedure was applied to three commercial pharmaceutical formulations with recoveries between 99.5 and 100.7% and agreed with a comparative HPLC procedure within 95% confidence level according to the Student’s t-test.