Microextraction and preconcentration of Mn and Cd from vegetables, grains and nuts prior to their determination by flame atomic absorption spectrometry using room temperature ionic liquid

Abstract

In this paper, a new and eco-friendly vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) procedure based on application of the room temperature ionic liquid (RTIL) 1-butyl-3-methylimidazolium chloride, [C4mim][Cl], followed by flame atomic absorption spectrometry (FAAS) was introduced for preconcentration and determination of trace amounts of Mn and Cd from vegetables, grains and nuts samples. The Mn(II) and Cd(II) ions were complexed with 1,3-dihydroxybenzene (Resorcinol) in presence of methanol containing the RTIL acting as both an extractant and auxiliary ligand at pH4.0 separately, and then extracted by IL at room temperature using a vortex mixer. Some important parameters affecting performance of the microextraction including pH, amount of IL and chelating ligand, volume of dispersive solvent, vortex time and rate, as well as effects of interfering species were optimized by univariate analysis. At optimized conditions, the limits of detection (defined as 3Sb/m) and sensitivity enhancement factors for Mn and Cd were determined as 0.15μgL−1, 0.25μgL−1, 150 and 110, respectively, with relative standard deviations (RSDs) <2.5%. The accuracy and precision were controlled and confirmed by analysis of certified reference materials (CRMs) using standard addition method. Lastly, the method was successfully applied to the determination of Mn and Cd in acid digested samples.