Separation of Ag(I) Ions from Lepidium draba L. Plant and Water and Standard Samples by Carrier Element-Free Coprecipitation Method Prior to their Flame Atomic Absorption Spectrometric Determination

In this work, silver iodide (Ag(I)) ions were separated via the carrier element-free coprecipitation (CEFC) method using an organic coprecipitating agent, 1,6-diamino-4-(4-chlornphenyl)-2-oxo-1,2-dihydropyridine-3,5-dicarbonitrile [DCODD] prior to its determination by ?ame atomic absorption spectrometry (FAAS). Analytical parameters including pH of aqueous solution, amount of DCODD, standing time, centrifugation rate and time, and sample volume were studied and optimized. Under the best experimental conditions, it was found that extraction can be performed from the sample volume of 500.0 for silver ion (preconcentration factor of 100.0). Linearity was maintained between 0.006 and 1.50 µg.mL^?1 for silver. Detection limit for silver based on 3Sb was 1.60 ng.mL^?1. The relative standard deviation of eight replicate measurements of 0.20 µg.mL^?1of silver was 2.10%. Finally, the developed method was successfully applied to extraction and determination of the silver ions in the Lepidium draba L plant, water and standard samples and satisfactory results were obtained.     

Preparation of Modified Magnetic Cobalt Nanoparticles as a New Magnetic Sorbent for the Preconcentration and Determination of Trace Amounts of Lead Ions in Environmental Water and Soil (Air-Dust) Samples

In this study, cobalt magnetic nanoparticles (MNPs) were synthesized and then modified by sodium dodecyl sulfate (SDS) and 2-(5-bromo-2-pyridylazo)-5-diethyl aminophenol ligand (5-Br-PADAP), through a chemical precipitation method. Characterization of the prepared MNP adsorbents was performed by Fourier transform infrared and transmission electron microscopy. Cobalt nanoparticles (NPs) surface modified with SDS and 5-Br-PADAP was evaluated as a nanoparticulate solid-phase extraction (SPE) absorbent for lead ions Pb(II) from water and standard samples, prior to its flame atomic absorption spectrometry determination. Effects of pH, amount of sorbent, desorption solvent, adsorption time, desorption time, and interfering ion concentration on extraction efficiency were investigated. Under optimal conditions, the calibration curve was linear in the range of 1.0–500 ng mL^?1of Pb(II) with R² = 0.998. Detection limit was 1.6 ng mL^?1 in the original solution (3S_b/m), and the relative standard deviation for replicate determination of 0.5 μg mL^?1 Pb(II) was ±2.7%.     

Determination of Trace Amounts of Cadmium Ions in Water and Plant Samples Using Ligand-Less Solid Phase Extraction-Based Modified Co3O4 Nanoparticles

In this study, a new Co₃O₄ nanoparticles (NPs) coated with sodium dodecyl sulphate (SDS) is developed for preconcentration of trace amounts of cadmium ions (Cd ²⁺) as a prior step to its determination by flame atomic absorption spectrometry (FAAS). The effects of various parameters, including pH of sample solution, amount of sorbent, flow rates of solution and eluent, sample volume, type, and least amount of the eluent for elution of the Cd ²⁺ from Co₃O₄ NPs were studied and optimized. Experimental conditions for effective separation of trace levels of the Cd ²⁺were optimized with respect to different experimental parameters in Column method. Under the best experimental conditions, the calibration curve was linear in the range of 1.0–500.0 ng.mL^?1 of cadmium (Cd) with R² = 0.999. The detection limit was 0.4ng.mL^?1 in the original solution (3S_b/m) and the relative standard deviation for eight replicate determination of 0.1µg.mL^?1 Cd was ±2.1%. The method was validated by the analysis of a certified reference material with the results being in agreement with those quoted by manufactures. The developed method was successfully applied to the extraction and determination of Cd in water and food samples with satisfactory results.