A Natural Deep Eutectic Solvent-based Ultrasound-Vortex-assisted Dispersive Liquid-Liquid Microextraction Method for Ligand-less Pre-concentration and Determination of Traces of Cadmium Ions in Water and Some Food Samples

A very explicate and ligand-less ultrasound-vortex-assisted dispersive liquid-liquid microextraction (US-VA-DLLME) technique has been designed for the pre-concentration and extraction of ultra-trace amounts of cadmium ions, before its determination by graphite furnace atomic absorption spectrophotometry. In the proposed approach, a hydrophobic natural deep eutectic solvent (NADES), prepared from combination of salicylic acid (SA) and l-menthol (M), was studied as both the extraction solvent and the complexing agent for the extraction of cadmium ions. Some significant factors influencing the microextraction performance including pH, volume of DES, sonication time, and extraction temperature were carefully examined and optimized. The calibration curve, obtained under the optimal extraction and instrumental parameters for determination of cadmium, exhibited a wide linearity over the range of 0.001-7.5 mu gL(-1) (R-2 =0.9953). The proposed method provided low limits of detection (LOD) and quantification (LOQ) of 0.37 x 10(-4) and 1.24 x 10(-)4 mu gL(-1), respectively. The relative standard deviation (RSD) and pre-concentration factor (PF) were also evaluated as 2.65% and 125, respectively. Finally, the developed US-VA-DLLME technique was favorably applied to the separation and determination of ultra-traces of cadmium in several waters and food samples.

Automated summary

A new ultrasound-vortex-assisted dispersive liquid-liquid microextraction (US-VA-DLLME) technique was designed for the pre-concentration and extraction of ultra-trace amounts of cadmium ions, and successfully applied to the separation and determination of cadmium in water and food samples.