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In the present article, a simple, rapid, sensitive and economical method has been developed for the simultaneous separation
and preconcentration of the trace amounts of copper, nickel, cobalt and manganese in water samples by using modified XAD-4
resins. The sorption was quantitative in the pH range 6.0–9.0, whereas quantitative desorption occurred instantaneously with
5.0 mL of 2 M HNO3, and selected elements have been determined by using flame atomic absorption spectrometry. Dynamic ranges were 0.04–3.5,
0.1–6.0, 0.04–4.5 and 0.04–4.0 μg/mL for copper, nickel, cobalt and manganese, respectively. The detection limits were 9.2,
28.6, 12.3 and 5.7 ng/mL for Cu(II), Ni(II), Co(II) and Mn(II), respectively. The effects of the experimental parameters,
including the sample pH, eluent type, interference ions and breakthrough volume, were studied for separation and preconcentration
of Cu(II), Ni(II), Co(II) and Mn(II) ions. Determination of these ions in standard samples confirmed that the proposed method
has good accuracy. The proposed method was used for the determination of these ions in water samples. 相似文献
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Sensitive and selective determination of phenylhydrazine in the presence of hydrazine at a ferrocene-modified carbon nanotube paste electrode 总被引:1,自引:0,他引:1
Dariush Afzali Hassan Karimi-Maleh Mohammad Ali Khalilzadeh 《Environmental Chemistry Letters》2011,9(3):375-381
The determination of hydrazine derivatives is of special interest because they are toxic and widely used in industry, agriculture
and explosives. Electrochemical analysis has become of growing importance in industrial process control, environmental monitoring,
and different applications in medicine and biotechnology. In the present work, we used a carbon paste electrode modified by
ferrocene and carbon nanotubes for simultaneous determination of phenylhydrazine and hydrazine. The modified electrode showed
an excellent character for electrocatalytic oxidization of phenylhydrazine and hydrazine with a 310 mV separation of both
peaks. Differential pulse voltammetric peak currents of phenylhydrazine and hydrazine increased linearly with their concentrations
at the range of 0.85–700 and 16–800 μM, and the detection limits (3σ) were determined to be 0.6 and 14 μM, respectively. Here,
we show that this electrode could be used as an electrochemical sensor for determination of phenylhydrazine and hydrazine
in real samples (water and urine) with advantages such as short time of analysis, lack of pretreatment procedures and more
cheaper in comparison with some routine analysis methods such as chromatography or spectroscopy. The modified electrode showed
good reproducibility, remarkable long-term stability, and especially good surface renewability by simple mechanical polishing. 相似文献
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A simple and rapid ligand-less in situ surfactant-based solid phase extraction method for preconcentration of silver from water samples is developed. In this method, a cationic surfactant containing a proper alkyl group (n-dodecyltrimethylammonium bromide) is dissolved in the aqueous sample and then a proper ion-pairing agent (ClO4?) is added. Due to the interaction between surfactant and ion-pairing agent, solid particles are formed and used for adsorption of silver carbonate. After centrifugation, the sediment is dissolved in 2.0 mL 1 M HNO3 in ethanol and then aspirated directly into the flame atomic absorption spectrometer. Variables affecting the extraction efficiencies such as pH, concentrations of surfactant and CO32?, ion pair concentration, and extraction time, are optimized. Under such conditions, the calibration curve is linear from 3 to 700 μg L?1. Detection limit is 1.1 μg L?1 with an enrichment factor of 37. The relative standard deviation for eight replicate measurements of 100 μg L?1 is 2.1%. The method has been applied for the determination of silver in water samples. 相似文献
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Daryoush Afzali Fariba Fathirad Sima Ghaseminezhad Zahra Afzali 《Environmental monitoring and assessment》2014,186(6):3523-3529
In this study, a ternary Zr(IV) system with 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol (5-Br-PADAP) and fluoride was chosen on the basis of dispersive liquid–liquid microextraction method. Zirconium was extracted into the fine droplets of dichlorobenzene as extracting solvent. These drops dispersed as a cloud in the aqueous sample with the help of ultrasonic waves, and the procedure was done. Finally, atomic absorption spectrometry was applied for the determination of zirconium. The effects of different factors that influence complex formation and extraction, such as pH, amounts of complexing agents, type and volume of the extracting solvent, as well as sonication and centrifuging time, were optimized. Under optimum conditions, the calibration curve was linear in the range of 150.0–800.0 ng mL?1 with a limit of detection of 44.0 ng mL?1. Relative standard deviation was calculated to be 4.1 % (n?=?7, c?=?400.0 ng mL?1). The enrichment factor was 80. The proposed method was successfully used to determine the zirconium in several water, wastewater, and soil samples. 相似文献
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Ghasem Sargazi Daryoush Afzali Ali Mostafavi S. Yousef Ebrahimipour 《Journal of Polymers and the Environment》2018,26(5):1804-1817
In this study, we have showed a facile route for fabrication of a novel microporous material based on chitosan (CS) and poly(vinyl alcohol) (PVA) biodegradable nanofibers that have high specific surface area, considerable porosity, and small diameter. Scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, fourier transform infrared spectroscopy, Brunauer–Emmett–Teller surface area analysis, and CHNS/O elemental analyser were applied to characterize the fabricated CS/PVA composite nanofibers. Moreover, the influences of spinning conditions including concentration, voltage, electrospinning distance, and flow rate, on size distribution and pore diameter of the final product were systematically studied using 2k?1 factorial design experiments, and the response surface optimization was used for determining the best synthesis parameter. The results obtained from 2K?1 factorial design experiments showed that electrospinning parameters influenced the size distribution and pore diameter of the CS/PVA microporous material. Based on the response surface methodology, the CS/PVA product could be obtained with a high microporous diameter of 1.8 nm and a small diameter distribution of 15.0 nm under optimized conditions. The obtained results showed that the fabricated samples could be utilized in different applications. 相似文献
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In the present work, determination of ultratrace amounts of thallium in water samples was performed by ultrasound-assisted emulsification microextraction based on solidification of a floating organic drop as sample preparation method prior to furnace atomic absorption spectrometry. 1-(2-Pyridylazo)-2-naphthol was used as chelating agent. The factors influencing the complex formation and extraction, such as pH of the aqueous solution, the type and the volume of extraction solvent, the volume of chelating agent solution, and the extraction time were investigated. Under optimized conditions, the enrichment factor was 200. The calibration graph was linear from 0.2 to 10.0 μg L?1 with a correlation coefficient of 0.9966, the detection limit was 0.03 μg L?1 and reproducibility was ±3.3% (C = 5.0 μg L?1, n = 8). The method was successfully applied for the determination of thallium in water samples. 相似文献
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