Multi-element determination of Cd, Pb, Cu, V, Cr, and Mn in ethanol fuel samples using energy dispersive X-ray fluorescence spectrometry after magnetic solid phase microextraction using CoFe2O4 nanoparticles

In this study, multi-element determination in ethanol fuel samples using energy dispersive X-ray fluorescence spectrometry (EDXRF) combined with magnetic solid phase microextraction (MSPME) was explored. The extraction and preconcentration of Cd, Pb, Cu, V, Cr, and Mn from ethanol fuel samples using CoFe2O4 nano- particles impregnated with 1-(2-pyridylazo)-naphthol (PAN) was carried out for posterior direct determination in the solid phase using EDXRF. Factors such as the concentration of PAN, pH value, time of extraction, and sample volume were optimized. Under the optimized conditions, linear calibration curves were obtained. The precisions for the determination of each element, expressed as relative standard deviations (RSD) of standard solutions containing 0.20 mg L-1 of Cu, Cd, Pb, Cr, V, and Mn and calculated from ten consecutive measure- ments, were 1.6, 2.8, 2.8, 4.0, 1.5, and 4.5%, respectively. The proposed method allowed the determination of metals with detection limits of 0.012, 0.013, 0.016, 0.012, 0.009, and 0.011 mg L-1 for Cu, Cd, Pb, Cr, V, and Mn, respectively. The method was successfully applied to the extraction and determination of Cd, Pb, Cu, V, Cr, and Mn in ethanol fuel samples.