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

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 mu A mu M-1 cm(-2) for AC and 6.5 mu A mu M-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 mu M and 0.05-1-170 mu M 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.