Solid phase extraction of chromium(VI) from aqueous solutions by adsorption of its diphenylcarbazide complex on a mixed bed adsorbent (acid activated montmorillonite-silica gel) column
ABSTRACT A novel approach has been developed for the solid phase extraction of chromium(VI) based on the adsorption of its diphenylcarbazide complex on a mixture of acid activated montmorillonite (AAM)-silica gel column. The effect of various parameters such as acidity, stability of the column, sample volume, interfering ions, etc., were studied in detail. The adsorbed complex could be easily eluted using polyethylene glycol-sulfuric acid mixture and the concentration of chromium has been determined using visible spectrophotometry. The calibration graph was linear in the range 0-1microgmL(-1) chromium(VI) with a detection limit of 6microgL(-1). A highest preconcentration factor of 25 could be obtained for 250mL sample volume using glass wool as support for the mixed bed adsorbent. Chromium(VI) could be effectively separated from other ions such as nickel, copper, zinc, chloride, sulfate, nitrate, etc., and the method has been successfully applied to study the recovery of chromium in electroplating waste water and spiked water samples.
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ABSTRACT: A solid phase extraction procedure has been established for chromium speciation in natural water samples prior to determination by atomic absorption spectrometry. The procedure is based on the solid phase extraction of the Cr(VI)- Dowex M 4195 chelating resin. After oxidation of Cr(III) to Cr(VI) by using H2O2, the presented method was applied to the determination of the total chromium. The level of Cr(III) is calculated by difference of total chromium and Cr(VI) levels. The procedure was optimized for some analytical parameters including pH, eluent type, flow rates of sample and eluent, matrix effects, etc. The presented method was applied for the speciation of chromium in natural water samples with satisfactory results (recoveries >95%, RSDs <10%). In the determinations of chromium species, flame atomic absorption spectrometer was used. The results were checked by using NIST SRM 2711 Montana soil and GBW 07603 Bush branched and leaves.Journal of Hazardous Materials 05/2008; 153(3):1009-14. DOI:10.1016/j.jhazmat.2007.09.051 · 4.53 Impact Factor
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ABSTRACT: A solid phase extraction (SPE) preconcentration system, coupled to a flame atomic absorption spectrometer (FAAS), was developed for the determination of copper(II), cadmium(II), lead(II), manganese(II), iron(III), nickel(II) and cobalt(II) ions at the microg L(-1) levels on Penicillium italicum-loaded on Sepabeads SP 70. The analytes were adsorbed on biosorbent at the pH range of 8.5-9.5. The adsorbed metals were eluted with 1 mol L(-1) HCl. The influences of the various analytical parameters including pH of the aqueous solutions, sample volume, flow rates were investigated for the retentions of the analyte ions. The recovery values are ranged from 95-102%. The influences of alkaline, earth alkaline and some transition metal ions were also discussed. Under the optimized conditions, the detection limits (3s, n=21) for analytes were in the range of 0.41microg L(-1) (cadmium) and 1.60microg L(-1) (iron). The standard reference materials (IAEA 336 Lichen, NIST SRM 1573a Tomato leaves) were analyzed to verify the proposed method. The method was successfully applied for the determinations of analytes in natural water, cultivated mushroom, lichen (Bryum capilare Hedw), moss (Homalothecium sericeum) and refined table salt samples.Journal of Hazardous Materials 05/2008; 152(3):1171-8. DOI:10.1016/j.jhazmat.2007.07.097 · 4.53 Impact Factor
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ABSTRACT: This is the first Atomic Spectrometry Update (ASU) to focus specifically on developments in elemental speciation and covers a period of 10 months from January 2008. Other ASU reviews1–5 detail aspects of the research in this area, but our aim is to bring all of the work on this subject together in a single review. This new development comes as a result of the importance of the currency of the ASU reviews as a series. As a consequence of the continued and growing interest in the area of elemental speciation, which is evidenced by the volume of primary and review literature on the subject and the emergence of scientific meetings focusing on the topic, it was decided to instigate a radical change to the ASU series, culminating in the development of this new Update. Speciation has been considered by the International Union for Pure and Applied Chemistry (IUPAC) who have published guidelines6 for its definition, which are as follows: speciation analysis is the analytical activity of identifying and/or measuring the quantities of one or more individual chemical species in a sample; the chemical species are specific forms of an element defined as to isotopic composition, electronic or oxidation state, and/or complex or molecular structure; the speciation of an element is the distribution of an element amongst defined chemical species in a system. This review will therefore deal with all aspects of the analytical speciation methods developed for: the determination of oxidation states; organometallic compounds; coordination compounds; metal and heteroatom-containing biomolecules, including metalloproteins, proteins, peptides and amino acids; and the use of metal-tagging to facilitate detection via atomic spectrometry. Applications in the areas of environmental science, clinical and pharmaceutical analysis, food, industrial and related areas will be covered. The review will not specifically deal with operationally defined speciation, but will highlight other reviews which cover the work in this area. As with all ASU reviews, the coverage of the topic is confined to those methods that incorporate atomic spectrometry as the measurement technique. However, in the spirit of meeting the needs of the subject, we will incorporate material that is not strictly “atomic spectrometry”. For the most part, such procedures are those in which some form of molecular MS is the measurement technique. There is a growing role for this kind of MS either as the sole instrumental technique or quite literally, in parallel with an elemental detector. As the contents of this Update show, there is considerable activity in the development and application of methods of elemental speciation analysis, which for some elements and combinations of techniques is a mature field as shown by the extent to which relevant topics have been the subject of reviews and book chapters.Journal of Analytical Atomic Spectrometry 01/2009; 24(8-8):999-1025. DOI:10.1039/B911133F · 3.47 Impact Factor