Sm2O3 nanorod-modified graphite paste electrode for trace level voltammetric determination of acetaminophen and ciprofloxacin

Abstract

Samarium oxide (Sm₂O₃) nanorods were synthesized through a sol–gel method in the presence of poly(ethylene glycol) as a structure-directing subagent. The transformation of the crystalline phase, crystallinity, bonding configurations, and morphology with calcination temperature was investigated by using powder X-ray diffraction, FESEM, XPS, and TEM. Furthermore, various spectroscopic analyses were done using FTIR, UV-Vis, and photoluminescence. A composite of Sm₂O₃ nanorods and graphite was used to prepare an electrochemical sensor for the detection of two different drug molecules in a binary mixture, namely acetaminophen (AC) and ciprofloxacin (CP). The effects of the crystalline phase on the electrocatalytic activity were analyzed. The modified electrode showed high sensitivity (93 μA μM⁻¹ cm⁻² for AC and 6.5 μA μM⁻¹ cm⁻² for CP) towards the drug molecules during the voltammetric determination. An optimized composition (3 : 7 Sm₂O₃ : graphite) of the modified electrode showed the best analytical performance. The strongest differential pulse voltammetric oxidation peaks for AC and CP were at around 533 ± 3 mV and 976 ± 043 mV, respectively. Anodic oxidation peaks were well-separated for effective analysis within a mixture. The sensor response was linear within the concentration range of 0.001–0.01–300 μM and 0.05–1–170 μM for AC and CP, respectively. The detection limits were 0.1 nM for AC and 5 nM for CP (S/N 3). The Sm₂O₃-9-3/GP electrode showed excellent analytical performance when analyzing spiked urine and pharmaceutical samples.