Ionic Liquid-Solidified Floating Organic Drop Microextraction for the Preconcentration of Lead in Environmental Water Samples Prior to Its Determination with Electrothermal Atomic Absorption Spectrometry

This research investigates the utilization of an ionic liquid combination of solidified floating organic drop micro-extraction (IL-SFODME) to augment the concentration of trace amounts of lead, working as a preliminary stage before electrothermal atomic absorption spectrometry (ETAAS) analysis without the use of chelating agents. Key parameters impacting the microextraction efficiency-including pH, the volume of the ionic liquid (1-Hexyl-3-methylimidazolium hexafluorophosphate, HMIMPF6), temperature, extraction time, and stirring speed-were methodically examined to determine optimal conditions. Under detected optimized conditions, an enhancement factor of 71.2 was obtained for a 15 mL sample solution. The calibration curve exhibited linearity within the concentration range of 0.2-2.5 µg/L, with a detection limit (3σ) of 0.054 µg/L and a quantification limit (10σ) of 0.18 µg/L. For seven replicate measurements of 0.5 µg/L lead, the relative standard deviation (RSD) was ±2.30%. This method was effectively implemented to extract and quantify lead in both reference water and different real water samples, showcasing significantly efficient extraction performance.

Efficient lead preconcentration using two chemically functionalized carbon nanotubes in hyphenated flow injection-flame atomic absorption spectrometry system

Lead contamination in drinking and natural water has reached alarming concentrations, thus necessitating the development of accurate and rapid determination systems for Pb(II) in aqueous systems. Two hyphenated flow injection-solid phase extraction- FAAS (FI-SPE-FAAS) systems using oxidized and m-phenylenediamine functionalized multiwalled carbon nanotubes for Pb(II) preconcentration from industrially contaminated real water samples have been proposed. The chemical and hydrodynamic parameters affecting Pb(II) sorption/desorption were optimized. The effect of common interfering ions in water was also studied. Different figures of merit such as preconcentration factor (> 70), detection limit (≤ 1.5 µg L^-1), and relative standard deviation (≤ 1.3%) were achieved at the preconcentration time of 120 s for both the preconcentration systems. The method was applied to industrially contaminated real water samples and the spike recovery tests were carried out using standard Pb(II) solution traceable to NIST. The proposed method was validated using standard reference material 1640a supplied by NIST Gaithersburg, MD, USA.

Application of Deep Eutectic Solvent Modified Cotton as a Sorbent for Online Solid-Phase Extraction and Determination of Trace Amounts of Copper and Nickel in Water and Biological Samples

Deep eutectic solvent (DES) was used as the extractant to improve the extraction properties of cotton. DES of choline chloride-urea (ChCl-urea) was prepared and immobilized on the surface of cotton fibers. The resulting sorbent was packed on a microcolumn, and a flow injection flame atomic absorption spectrometry was designed for the online separation and determination of trace amounts of copper and nickel. Various parameters affecting the extraction recovery of analytes such as pH, sample volume, sample loading rate, nature, volume, concentration, and flow rate of eluent were investigated and optimized. Under the optimum conditions, the method showed good linearity in the concentration range of 0.25-50.0 and 4.0-125.0 μg L^-1 with the coefficient of determination (r ²) of 0.9991 and 0.9990 for copper and nickel, respectively. The method was very sensitive with the detection limits (defined as 3S_b/m) of 0.05 and 0.60 μg L^-1 for Cu and Ni, respectively. It was successfully applied for the determination of Cu and Ni in water and biological samples. The accuracy of the method was evaluated through the recovery experiments and independent analysis by electrothermal atomic absorption spectrometry.

Trace level enrichment of lead from environmental water samples utilizing dispersive liquid-liquid microextraction and quantitative determination by graphite furnace atomic absorption spectrometry

Dispersive liquid-liquid microextraction (DLLME) was developed and successfully applied, as a sample preconcentration and extraction method, for the determination of trace quantities of lead (Pb) in environmental water samples utilizing graphite furnace atomic absorption spectrometer (GFAAS). Experimental parameters optimized include; extraction and disperser solvent types and their volumes, pH, extraction period, effect of the co-existing ions and the amount of chelating agent, ammonium pyrrolidine dithiocarbamate (APDC). Under the optimized conditions, enrichment factor of 195 at 5 μg L(-1) level and detection limit of 0.16 μg L(-1) were obtained. Linearity from 25-75 μg L(-1) with R(2) of 0.995 was achieved. The procedure was validated utilizing four environmental water samples at the spiking levels of 10 and 20 μg L(-1) and the corresponding recoveries ranged from 89.6 to 95.1% and 91.6 to 97.1%, respectively, indicating the reliability and applicability of the method for selective extraction of trace level lead.

Pyridine-2,6-diamine-functionalized Fe₃O₄ nanoparticles as a novel sorbent for determination of lead and cadmium ions in cosmetic samples

A novel sorbent based on pyridine-2,6-diamine-functionalized Fe(3)O(4) nanoparticles was developed and characterized by X-ray powder diffraction (XRD), elemental analysis, IR spectroscopy and scanning electron microscopy (SEM). The application of the sorbent was investigated for pre-concentration and determination of lead and cadmium ions in aqueous samples. Effects of various factors such as the sample pH, eluent parameters (type, concentration and volume) and time (adsorption and desorption) were appraised. The effects of several interfering ions on method recovery were also investigated. The limit of detection (LOD) was found to be 1.3 and 0.089 μg L(-1) for lead and cadmium ions, respectively. Recovery and precision (RSD%) of the method were above 97.9% and below 0.6%, respectively. Validation of the outlined method was performed by analysing several certified reference materials. This method was successfully used for determination of lead and cadmium ions in several cosmetic samples, which are usually contaminated by lead and cadmium ions.