Flame atomic absorption spectrometric determination of total chromium and cadmium in bean samples after ultrasonic-assisted microextraction using ionic liquid Aliquat-336

Abstract

A new and rapid microextraction approach termed as ultrasonic-assisted ionic liquid-based microextraction (UA-ILME) was developed using ionic liquid Aliquat-336 as extraction solvent for the extraction of chromium and cadmium in bean samples collected from different regions in Turkey. The total amounts of analytes in the samples were measured by flame atomic absorption spectrophotometry. The basis of the extraction step is based on the complexation of Cr(III) and Cd(II) with diethyldithiocarbamate at pH 4.0. The hydrophobic ternary complexes containing analytes were then rapidly extracted from the sample solution to the ionic phase under the ultrasonic effect using tricaprylylmethylammonium chloride (Aliquat-336). Some experimental variables (pH, ligand amount, extraction solvent volume, ultrasound time, extraction temperature and sample volume) were optimized in detail. Following the optimization steps, the limits of detection (LODs, 3Sblank/m) for Cr(III) and Cd(II) were calculated as 0.45 ng mL−1 with linear range of 1.5–380 ng mL−1 and 0.25 ng mL−1 with linear range of 0.8–220 ng mL−1, respectively. Enrichment factors and average recoveries were ranged from 125.8–96.4 to 92.7–106.5%, respectively. The accuracy and precision of the method were validated by analyzing a certified reference material and spiked recovery tests. The UA-ILME method was successfully applied to the determination of Cd and Cr in the samples, highlighting that the matrix ions under consideration do not affect the extraction and determination steps.