Sensitive spectrophotometric determination of fluoxetine from urine samples using charge transfer complex formation after solid phase extraction by magnetic multiwalled carbon nanotubes

Abstract

In this study, magnetic multiwalled carbon nanotubes (MWCNTs/Fe₃O₄) were prepared by assembling magnetic nanoparticles onto the acid-treated multiwalled carbon nanotubes, and because of their excellent adsorption capability, the MWCNTs/Fe₃O₄ nanocomposites were used as the adsorbent in a magnetic solid phase extraction procedure (MSPE) to extract fluoxetine from human urine samples. A spectrophotometric detection was performed by the drug reaction with a π-acceptor reagent, 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in nonaqueous media via the formation of a charge transfer complex and by coupling MSPE with visible detection, and a reliable, sensitive and cost-effective method for the determination of trace amounts of fluoxetine was developed. The main factors affecting extraction efficiency and complex formation, including the pH of the sample solution, extraction and desorption time, desorption conditions, sample volume, amount of magnetic adsorbent, DDQ volume and complexation time, were investigated. Under the optimized conditions, the calibration curve was linear (R² ≥ 0.9995) over the concentration range of 0.15 to 2.5 μg mL⁻¹ with an LOD and LOQ of 0.06 and 0.19 μg mL⁻¹, respectively. The relative standard deviation (RSD%) of 2.6% (n = 6) for 1 μg mL⁻¹ and the enrichment factor of 48 was achieved. The method was successfully applied to the extraction and preconcentration of fluoxetine from human urine samples.