Dual In-Syringe Microextraction with Electrothermal Vaporization (ETV) Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) for Determination of Rare Earth Elements (REEs) in Food

In-syringe micro-solid phase extraction (IS-MSPE) was coupled with in-syringe vortex-assisted solidified floating organic drop microextraction (IS-VA-SFODME) for the determination of rare earth elements (REEs) by electrothermal vaporization inductively coupled plasma-mass spectrometry. Firstly, IS-MSPE was used for enriching REEs and eliminating the matrix components from samples. In the next step, the eluent from IS-MSPE was utilized for further enrichment of REEs by IS-VA-SFODME. This procedure exhibited high efficiency and good selectivity without tedious centrifugation/filtration operations. The primary factors affecting preconcentration, separation and determination of REEs were investigated. The enrichment factors (EFs) ranged from 267-fold to 523-fold for REEs. Under the optimized conditions, the detection limits for REEs were from 0.002 to 0.065 ng L--(1) with relative standard deviations between 4.6 and 9.1%. This method was used for the determination of REEs in food certified reference materials, and the determined results were in good agreement with the certified values.