A Simple Organic Solvent-Free Liquid-Liquid Microextraction Method for the Determination of Potentially Toxic Metals as 2-(5-Bromo-2-pyridylazo)-5-(diethylamino)phenol Complex from Food and Biological Samples

Abstract

An organic solvent-free method was developed to extract some potentially toxic metals, as complexed with 2-(5-bromo-2-pyridylazo)-5-(diethylamino)phenol, from different real samples prior to their determination by microsampling flame atomic absorption spectrometry. The method, named ionic liquid-based ultrasound-enhanced air-assisted liquid-liquid microextraction (IL-USE-AALLME), is based upon withdrawing and pushing out a mixture of an aqueous sample and an IL (as the extraction solvent) for several times into a conical test tube using a single syringe, placed in an ultrasound bath (as the enhancing mass transfer agent) during the extraction process. Different effective parameters were studied, and at the optimized conditions, limits of detection, linear dynamic ranges, and enrichment factors were ranged from 0.9 to 2.2 μg L(-1), 3.0 to 1023 μg L(-1), and 20 ± 2 to 22 ± 2, respectively. After optimization, the method was successfully applied to determine Pb(2+), Cu(2+), Co(2+), Ni(2+), and Cr(3+) in different biological (hair and nail), vegetable (coriander, parsley, and tarragon), fruit juice (apple, orange, and peach), and water (tap, mineral, and wastewater) samples. The proposed method was compared with two other IL-based and disperser solvent-free methods (i.e., IL-based air-assisted liquid-liquid microextraction and IL-based ultrasound-assisted emulsification microextraction) to demonstrate its performance.

Ultrasound-assisted ionic liquid-based dispersive liquid-liquid microextraction procedure for preconcentration of cobalt and nickel in environmental and biological samples prior to FAAS determination

“…Enrichment and separation techniques are required to analyze Co(II) and Ni(II) at trace levels due to low metal concentrations and matrix interferences in actual samples. Several enrichment procedures have been developed for the determination of Co(II) and Ni(II), involving various analytical techniques such as coprecipitation [13][14][15][16][17][18][19], liquid-liquid microextraction [20][21][22][23][24][25], cloud point extraction [26][27][28][29][30][31], membrane filtration [32,33], and solid-phase extraction [34][35][36][37][38][39][40][41].…”

Reverse ultrasound-assisted emulsification-microextraction of macrolides from chicken fat followed by electrophoretic determination

“…Even though DLLME is a low-cost simple method which generally uses small amounts of organic solvents as extractant and/or dispersant, these solvents are still highly toxic. In order to solve this problem, the use of environmentally friendly extraction solvents, such as ionic liquids (ILs) and the replacement of the dispersive solvents by ultrasound energy, vortex, temperature, among others, are a good solution (Barfi, Rajabi, & Asghari, 2015).…”