Optimized syringe-assisted dispersive micro solid phase extraction coupled with microsampling flame atomic absorption spectrometry for the simple and fast determination of potentially toxic metals in fruit juice and bio-fluid samples

Abstract

In this work, a novel method called Syringe-assisted dispersive micro solid phase extraction (SA-DM-SPE) was developed based on repeatedly withdrawing and pushing out a mixture of an aqueous sample including some chelated potentially toxic metal ions with bis-(acetylacetone) ethylenediimine and a low level of a suitable adsorbent (1.6 mg of multi-walled carbon nanotubes) in a test tube using a syringe. Since maximum contact surface areas were simply provided between the chelated ions and adsorbent with no need to essentially off-line the accelerating mass transfer (including sonication and vortex) and centrifugation steps, maximum efficiency was achieved within a short period of time. The optimized conditions for the extraction of Pb²⁺, Cd²⁺, Co²⁺, Ni²⁺, and Cr³⁺, as target ions, were investigated by the experimental design strategy. Under the optimum conditions, limits of detection, linear dynamic ranges, consumptive indices, and repeatabilities (in terms of intra-day precisions) ranged from 0.3 to 2.0 μg L⁻¹, 0.9 to 980 μg L⁻¹, ∼0.33, and 3.4 to 4.2, respectively. The method was successfully applied to the determination of target ions in different water (tap and wastewater), fruit juice (apple, pear, grape, and grapefruit), and biological fluid (saliva and urine) samples using a microsampling flame atomic absorption spectrometry (MS-FAAS) technique.