Nanoparticles consisting of magnetite and Al₂O₃ for ligandless ultrasound-assisted dispersive solid phase microextraction of Sb, Mo and V prior to their determination by ICP-OES

The authors have developed a rapid and efficient preconcentration method for speciation of Mo(VI), Sb(V) and V(V) that is based on ligandless ultrasound-assisted dispersive solid phase microextraction (UDSPME) using Fe₃O₄@Al₂O₃ nanoparticles (NPs) as a sorbent. The NPs were characterized using XRD, SEM, EDX and surface area (BET). The experimental parameters affecting the preconcetration system were optimized using fractional factorial design. The target analytes were preconcetrated, eluted with dilute nitric acid, and then determined by ICP-OES. Under optimum conditions, the limits of detection (for n = 20) for the analytes range from 0.16 to 0.18 ng L⁻¹ and the limits of quantification range from 0.5 to 0.6 ng L⁻¹. The repeatability (intra-day precision; for n = 15) and reproducibility (inter-day precision; for n = 7) ranged from 2.1 to 3.9 % and 4.5 to5.3 %, respectively. The accuracy of the UDSPME method was checked by analysing certified reference material (CRM) and standard reference materials (SRM). Finally, a non-chromatographic method was developed for speciation of Mo, Sb and V at trace levels and successfully applied for the determination of analytes in environmental water samples. [Figure not available: see fulltext.]