Application of a Magnetic Multi-Wall Carbon Nanotube Sorbent for Extraction and Determination of Vanadium in Environmental Water Samples

For the first time, a novel and efficient Magnetic Multi-Wall Carbon NanoTube (MMWCNT) was introduced as a novel sorbent for Solid-Phase Extraction (SPE) coupled with ElectroThermal Atomic Absorption Spectrometry (ET-AAS) for sensitive determination of vanadium (V) in environmental water samples. Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), X-Ray Diffraction (XRD), Energy-Dispersive X-ray analysis (EDX), Vibrating Sample Magnetometry (VSM), and Fourier Transform-InfraRed (FT-IR) spectroscopy were applied to characterize the prepared nanoparticles. A unique and attractive property of this method is that magnetic adsorbents can be simply isolated from sample solutions by an external magnetic field without using a centrifuge. N-Benzoyl-N-phenylhydroxylamine (BPHA) was used as a complexing agent for extraction of the analyte into the solid phase. The extracted complex was injected into the instrument for analysis. Initially, effective parameters controlling the performance of the extraction process were evaluated and optimized. Under the optimized condition, the calibration curve showed linearity in the range of 25-2000 ng mL-1 with a regression coefficient corresponding to 0.997. Limits of detection (LOD, S/N = 3) and relative standard deviations were 8 ng mL-1 and 3.9 % (n = 6) respectively. The proposed method was successfully applied for the preconcentration and trace determination of V in environmental water samples while the accuracy was approved by analyzing relative recovery experiments as well as a standards reference material.