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The analytical performances of coupled chemical vapor generation, integrated atom trap (CVG-IAT) atomizer flame atomic absorption spectrometry (FAAS) system were evaluated for determination of nickel in environmental samples. Nickel chemical vapors are atomized in an air-acetylene flame-heated IAT. A new design of CVG-IAT-FAAS hyphenated technique that would exceed the operational capabilities of existing arrangements (a water-cooled single silica tube, double-slotted quartz tube) permitting construction of an “integrated trap” was investigated. An improvement in limit of detection was achieved compared with that obtained using any of the above atom trapping techniques separately. The concentration limit of detection was 1 ng mL−1 for Ni. The overall efficiencies of the vapor generation process was estimated to be ca. 50%. For a 2 min in situ pre-concentration time, sensitivity enhancement, compared to FAAS, was 200 folds for Ni, using vapor generation atom trapping technique. The sensitivity can be further improved by increasing the collection time. The precision of the measurements for 25 ng mL−1 of Ni was 9% RSD. The accuracy of this method was tested by analyses of NIST SRM 2704 (Buffalo River Sediment), NIST SRM 1648 (Urban Particulate Matter), NIST SRM 2710 (Montana Soil), NBS SRM 1633a (Coal Fly Ash) and NIST SRM 1643e (Trace Element in Water) certified reference materials. The measured Ni content in five reference materials was in satisfactory agreement with the certified values (in the range of 14.3–98 μg g−1). The hyphenated technique was applied for nickel determination in coal fly ash, soil, sediment, sewage and river water. [...]
EN
Brilliant green was used as a complexing agent in cloud point extraction (CPE) and applied for selective preconcentration of trace amounts of gold in geological matrices. The analyte in the initial aqueous solution was acidified with hydrochloric acid (0.1 M) and octylphenoxypolyethoxyethanol (Triton X-114) was added as a surfactant. After phase separation, based on the cloud point separation of the mixture, the surfactant rich phase was diluted with methanol and the analyte determined in the surfactant rich phase by flame atomic absorption spectrometry (FAAS). After optimization of the complexation and extraction conditions, a preconcentration factor of 31 was obtained for only 10 mL of sample. The analytical curve was linear in the range of 3–1000 ng mL−1 and the limit of detection was 1.5 ng mL−1. The proposed method was applied to the determination of gold in geological samples. [...]
EN
In the presented work, the conditions for cloud point extraction of iron from aqueous solutions using 7-iodo-8-hydroxyquinolin-5-sulphonic acid (Ferron) was investigated and optimized. The procedure is based on the separation of its ferron complex into the micellar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1.0 M HNO3 in methanol. Iron was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions were investigated. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for iron was 0.4 ng m L-1, enrichment factor of 19.6 and preconcentration factor of 30 could be achieved. The validity of cloud point extraction was checked by employing real samples including soil, blood, spinach, milk, meat, liver and orange juice samples using the standard addition method, which gave satisfactory results.In the presented work, the conditions for cloud point extraction of iron from aqueous solutions using 7-iodo-8-hydroxyquinolin-5-sulphonic acid (Ferron) was investigated and optimized. The procedure is based on the separation of its ferron complex into the micellar media by adding the surfactant Triton X-114. After phase separation, the surfactant-rich phase was dissolved with 1.0 M HNO3 in methanol. Iron was determined by flame atomic absorption spectrometry. Optimization of the pH, ligand and surfactant quantities, incubation time, temperature, viscosity, sample volume, and interfering ions were investigated. The effects of the matrix ions were also examined. The detection limits for three times the standard deviations of the blank for iron was 0.4 ng m L−1, enrichment factor of 19.6 and preconcentration factor of 30 could be achieved. The validity of cloud point extraction was checked by employing real samples including soil, blood, spinach, milk, meat, liver and orange juice samples using the standard addition method, which gave satisfactory results. [...]
EN
This paper describes, a new, sensitive, and low cost solid-phase extraction (SPE) method using a poly(N-phenylethanolamine) /multi-walled carbon nanotubes (MWCNTs) nanocomposite for extraction, pre-concentration, and flame atomic absorption spectrometric (FAAS) determination of trace level palladium in distilled water, tap water, Caspian sea water, Persian Gulf water, spring water, lake water and soil samples, as well as real samples. The poly(N-phenylethanolamine)/MWCNTs nanocomposite were characterized using Fourier Transform-infrared (FT-IR) spectroscopy, thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM). Factors affecting the pre-concentration of palladium, including sample pH, flow rate, and type and volume of eluent, were investigated. The effect of interfering ions and break through volume on the separation and determination of palladium ions was also determined. The maximum sorbent capacity of the poly (N-phenylethanolamine)/MWCNTs nanocomposite was calculated to be 101.5 mg g−1. The pre-concentration factor, relative standard deviation, and limit of detection of the method were found to be 150, 2.8% (n=10), and 0.09 ng mL−1, respectively. The presented method was compared to certified reference materials, and finally, the presented technique was applied to different matrices spiked with 5 ng mL−1 of analyte.
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