Solid-phase extraction and preconcentration of copper in mineral waters with 4-(2-pyridyl-azo) resorcinol-loaded amberlite XAD-7 and flame atomic absorption spectrometry

Pseudo-stir bar hollow fiber solid/liquid phase microextraction combined with anodic stripping voltammetry for determination of lead and cadmium in water samples

A new procedure is presented for the determination of low concentrations of lead and cadmium in water samples. Ligand assisted pseudo-stir bar hollow fiber solid/liquid phase microextraction using sol-gel sorbent reinforced with carbon nanotubes was combined with differential pulse anodic stripping voltammetry for simultaneous determination of cadmium and lead in tap water, and Darongar river water samples. In the present work, differential pulse anodic stripping voltammetry (DPASV) using a hanging mercury drop electrode (HMDE) was used in order to determine the ultra trace level of lead and cadmium ions in real samples. This method is based on accumulation of lead and cadmium ions on the electrode using different ligands; Quinolin-8-ol, 5,7-diiodo quinoline-8-ol, 4,5-diphenyl-1H-imidazole-2(3H)-one and 2-{[2-(2-Hydroxy-ethylamino)-ethylamino]-methyl}-phenol as the complexing agent. The optimized conditions were obtained. The relationship between the peak current versus concentration was linear over the range of 0.05-500 ng mL(-1) for Cd (II) and Pb (II). The limits of detection for lead and cadmium were 0.015 ng mL(-1) and 0.012 ng mL(-1), respectively. Under the optimized conditions, the pre-concentration factors are 2440 and 3710 for Cd (II) and Pb (II) in 5 mL of water sample, respectively.

Cloud point extraction and flame atomic absorption spectrometric determination of cadmium(II), lead(II), palladium(II) and silver(I) in environmental samples

The phase-separation phenomenon of non-ionic surfactants occurring in aqueous solution was used for the extraction of cadmium(II), lead(II), palladium(II) and silver(I). The analytical procedure involved the formation of understudy metals complex with bis((1H-benzo [d] imidazol-2yl)ethyl) sulfane (BIES), and quantitatively extracted to the phase rich in octylphenoxypolyethoxyethanol (Triton X-114) after centrifugation. Methanol acidified with 1molL(-1) HNO(3) was added to the surfactant-rich phase prior to its analysis by flame atomic absorption spectrometry (FAAS). The concentration of BIES, pH and amount of surfactant (Triton X-114) was optimized. At optimum conditions, the detection limits of (3 sdb/m) of 1.4, 2.8, 1.6 and 1.4 ng mL(-1) for Cd(2+), Pb(2+), Pd(2+) and Ag(+) along with preconcentration factors of 30 and enrichment factors of 48, 39, 32 and 42 for Cd(2+), Pb(2+), Pd(2+) and Ag(+), respectively, were obtained. The proposed cloud point extraction has been successfully applied for the determination of metal ions in real samples with complicated matrix such as radiology waste, vegetable, blood and urine samples.

Selective separation and preconcentration of copper (II) in environmental samples by the solid phase extraction on multi-walled carbon nanotubes

A solid phase extraction method for selective separation-preconcentration of copper (II) on multi-walled carbon nanotubes (MWNTs) prior to its flame atomic absorption spectrometric determinations has been investigated. The adsorption was achieved quantitatively on MWNTs column at pH 7.0, then the retained Cu(II) contents on the column were quantitatively eluted with 2M HNO(3). The effects of analytical parameters including pH of the solution, eluent type, sample volume, flow rates of eluent, matrix ions etc. were investigated for optimization of the presented procedure. The preconcentration factor was 60. The detection limit for copper (II) was found as 1.46 microg/L. The method was applied to the determination of copper in environmental samples and reproducible results were obtained.