On-line preconcentration/separation of inorganic arsenic and antimony by poly (aryl ether ketone) containing pendant carboxyl groups prior to microwave plasma atomic spectrometry determinations

Determination of Fe, Cu, and Pb in edible oils using choline chloride:ethylene glycol deep eutectic solvent-based dispersive liquid-liquid microextraction associated with microwave-induced plasma optical emission spectrometry

A new simple, fast and environmentally friendly deep eutectic solvent based dispersive liquid-liquid microextraction (DES-based DLLME) methodology assisted by vortex is presented for the separation and preconcentration of three elements (i.e., Fe, Cu and Pb) from edible oil samples (i.e., soybean, sunflower, rapeseed, sesame, and olive oil) prior to the determination by microwave-induced plasma optical emission spectrometry (MIP-OES). The deep eutectic solvent selected as extractant (i.e., choline chloride and ethylene glycol, 1:2) is synthesized and characterized by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance spectroscopy (1H NMR) and differential scanning calorimetry (DSC), and the extraction conditions are optimized by a two steps experimental design. Under the optimum extraction conditions (i.e., diluted sample weight: 8.6 g; DES volume: 100 μL; extraction time: 1 min; centrifugation time and speed: 3 min and 3000 rpm; and dispersion system: vortex) the analytical method presents excellent linearity (i.e., R2 values higher than 0.99) in the range 10-500 μg kg-1, repeatability (i.e., CV values lower than 9.2%), and limits of detection (LOD) values of 3, 2 and 0.7 μg kg-1 for Pb, Fe and Cu, respectively. None of the analytes displayed amounts over the upper limit permitted by law, and recovery values of all analytes evaluated in the different samples using external standard calibration were close to 100%, which excludes significant matrix effects. Finally, AGREEprep metric has been used to evaluate the method greenness (final score of 0.47) and it has been compared successfully with previous publications for the same type of analytes and matrices.

On-line electrochemical preconcentration and electrochemical hydride generation for determination of antimony by high-resolution continuum source atomic absorption spectrometry

Trace concentrations of antimony in aquatic samples were determined by high resolution continuum-source atomic absorption spectrometry (HR-CS AAS) after electrochemical pre-concentration and electrochemical hydride generation. Antimony was electrochemically deposited in a microporous glassy carbon electrode as elemental antimony then was electrochemically converted at the same electrode surface to antimony hydride which was transported by argon gas to the quartz cuvette of the spectrometer. The detection limit and precision of the method are below 0.1 μg L^-1 and 3-5%, respectively. The method was employed for the determination of antimony in a CRM and water samples including surface, underground and waste water.

Magnetic solid-phase extraction and determination of ultra-trace amounts of antimony in aqueous solutions using maghemite nanoparticles

A magnetic solid-phase extraction method was developed using maghemite as an efficient sorbent for the separation and preconcentration of antimony prior to its determination by ET-AAS. Maghemite was synthesized through a simple method and characterized by XRD, FT-IR and SEM. Various factors affecting maghemite synthesis, separation and preconcentration of antimony such as desorption solvent type, concentration and volume, desorption temperature and time, sample pH, amount of sorbent, and extraction temperature and time were optimized. The effects of interfering ions were also investigated. Under optimized conditions, the method exhibited good linearity (r² > 0.9960). The sorption capacity and enrichment factor (EF) of the method were 37.5 mg g^-1 and 242, respectively. The limit of detection (LOD) was 0.03 ng mL^-1. The intraday, interday, and batch-to-batch relative standard deviations (%RSDs) were quite reasonable. The proposed method was applied to various real samples and the relative recoveries found were between 95.8 and 104.0 %.

Ferric ion induced enhancement of ultraviolet vapour generation coupled with atomic fluorescence spectrometry for the determination of ultratrace inorganic arsenic in surface water

A novel method of ultraviolet vapour generation (UVG) coupled with atomic fluorescence spectrometry (AFS) was developed for the determination of ultratrace inorganic arsenic (iAs) in surface water.