نتایج جستجو برای: preconcentration
تعداد نتایج: 2262 فیلتر نتایج به سال:
A simple, reliable and rapid method for preconcentration and modification of silica gel with Isopropyl 2-[(isopropoxy carbothioyl)disulfanyl]ethanethioate(IIDE) in order to prepare an effective sorbent for the preconcentration and determination of lead. The sorption capacity of Isopropyl 2[(isopropoxy carbothioyl)disulfanyl]ethanethioate(IIDE)-modified silica-gel (IIDE MS) was 82.34 mg.g -1 a...
A simple and rapid vortex assisted ionic liquid based liquid-liquid microextraction technique (VALLME) was proposed for preconcentration of trace levels of cadmium. According to this method, the extraction solvent was dispersed into the aqueous samples by the assistance of vortex agitator. Cadmium preconcentration was mediated by chelation with the 8-hydroxyquinoline (oxine) reagent and an IL, ...
It is very important to investigate antimony geochemical behavior in order to identify its source, or reveal contamination processes, since antimony and its compounds are considered to be pollutants of high priority by the Environmental Protection Agency of the United States (USEPA). However, the concentration of antimony in most geological samples is very low, and its stable isotope mass diffe...
1-(2-pyridylazo) 2-naphtol (PAN) impregnated Ambersorb 563 resin was used as solid phase extractor of copper, nickel, cadmium, lead, chromium and cobalt ions in aqueous solutions prior to their atomic absorption spectrometric determinations. The parameters including pH, sample volume, matrix effects were also investigated. The relative standard deviation (R.S.D.) of the combined method of sampl...
A new method for the determination of cobalt was developed by dispersive liquid-liquid microextraction preconcentration and flame atomic absorption spectrometry. In the proposed approach, 1,5-bis(di-2-pyridyl) methylene thiocarbohydrazide (DPTH) was used as a chelating agent, and chloroform and ethanol were selected as extraction and dispersive solvents. Some factors influencing the extraction ...
A solid phase extraction (SPE) procedure was presented for the preconcentration of copper, nickel and cobalt using multiwalled carbon nanotubes (MWCNTs) modified by methyl-(2-pyridyl) ketone oxime (MPKO, as a new complexing agent) as a solid sorbent prior to their determination by flame atomic absorption spectroscopy (FAAS). Some analytical parameters including pH, sample volume, concentration ...
The increasing use of automobile catalysts leads to the emission of the platinum-group elements (PGE), mainly platinum, but also rhodium and palladium into the environment. In environmental samples, the low concentration of platinum together with the high concentration of interfering matrix components often requires a preconcentration/enrichment step combined with a matrix-separation. The metho...
A rapid flotation method for separation and enrichment of ultra trace amounts of copper(II), cadmium(II), nickel(II) and cobalt(II) ions from water samples is established. At pH 6.5 and with sodium dodecylsulfate used as a foaming reagent, Cu2+, Cd2+, Ni2+ and Co2+ were separated simultaneously with 2-aminocyclopentene-1-dithiocarboxylic acid (ACDA) added to 1 l of aqueous solution. The propose...
A method for the preconcentration and speciation of chromium in seawater was developed. On-line preconcentration and determination were carried out by using inductively coupled plasma atomic emission spectrometry (ICP-AES) with dual mini-columns containing a chelating resin. In this system, Cr(III) was collected on the first column. The effluent containing residual chromium from the first colum...
A direct sampling with organic solvent extracts for simultaneous multi-element determination implemented with inductively coupled plasma atomic emission spectrometry (ICP-AES) associated with a flow injection liquid-liquid extraction (FI-LLE) sample preconcentration method was studied. The "robustness" of the plasma discharge with tributyl phosphate (TBP) loading was diagnosed by using the Mg I...
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