Preconcentration Of Trace Metals Research Articles

Chelating polymers and related supports for separation and preconcentration of trace metals

This review is concerned mainly with the applications of chelating polymeric resins for the separation and concentration of trace metals from oceans, rivers, streams and other natural systems. Commercially available resins, specially prepared polymers and a selection of other sorbents are described and their uses outlined. Special emphasis is placed on the preconcentration of uranium from sea-water.

Maleic acid/ammonium hydroxide buffer system for preconcentration of trace metals from seawater

Maleic acid/ammonium hydroxide buffer system for preconcentration of trace metals from seawater

Characterization and optimization of HPIC for on-line preconcentration of trace metals with detection by ICP—mass spectrometry

The objective of this study was to investigate the feasibility of using a commercially available cation-exchange column for trace metal preconcentration. In addition, the advantages of interfacing the column to a highly sensitive element-selective detector were examined. A high-performance ion-chromatograph (HPIC) with a high-pressure pump and valve system was used to aid loading and delivery of the mobile phase. An inductively coupled plasma mass spectrometer combination (ICP—MS) was used as a detection device, with interfacing by means of a small diameter liquid-transport tube. The performance of the HPIC/ICP—MS combination was optimized by varying the concentration and flow-rate of two eluents (nitric acid and hydrochloric acid). The effects of varying the sample pH were assessed and the column capacity was determined by “breakthrough” tests. The elements copper, cadmium, mercury and lead were studied; the detection capability was dependent upon the sample volume loaded onto the column. The accuracy of the method was assessed by analysis of an “in house” reference standard.

Electrolytical microcell for on-line preconcentration of trace metals in flow systems

The separation of trace metals from solutions of electrolytes by electrodeposition in a 30 μl electrolytical flow-through cell was studied. The working electrode of the flow cell was made from powdered spectral or glassy carbon. The electrodeposition is complete for Cu2+, Cd2+, Mn2+ and Pb2+, partial for Zn2+, Fe3+ and Ni2+. Mn2+ and Pb2+ can also be deposited by anodic oxidation on the working electrode. The deposition is complete up to sample flow rates of 3–4 ml/min. The deposited elements are dissolved by short-circuiting the electrodes and flushing the cell with diluted acid. The dissolved elements are determined on-line by flame AAS. Data evaluation through peak area measurement is discussed.

On-line preconcentration and elution of trace metals by ion chromatography

On-line preconcentration of transition metal ions using 8-quinolinol-bonded chelating silica is described. The precolumn was coupled to an ion-pairing chromatographic column and simultaneous determination was achieved using a diode-array UV detector, 0.1 M potassium cyanide (pH 8.5) being used for eluting metals from both the precolumn and the analytical column. Of the metals tested, Cu, Ni, Co and Fe(II) yielded well resolved absorption bands whereas Fe(III) and Mn(II) yielded ill-characterized absorption bands. The working concentration range for Cu and Ni was tested and shown to be linear in the range 10 −8−5 · 10 −6 M. Highly reproducible results were obtained at these concentrations. The sensitivity was found to be limited by background signals and the reason for this background is discussed in detail.

Gallium Coprecipitation Associated with Magnesium for Preconcentration of Trace Metals in Seawater

Abstract The coprecipitation of trace metals with gallium has been investigated in detail especially with respects to the role of magnesium ion in saline or seawater. Gallium does not precipitate even at pH 9 when magnesium ion does not exist. The concentration of gallium in the precipitate increased with increasing that of magnesium in solution. The recoveries of trace metals also showed strong dependence on the concentrations of both gallium and magnesium in the aqueous solution.

Multielement preconcentration of trace metals from natural waters by solvent extraction with an alkylated oxine derivative

Kelex 100, a commercially available alkylated oxine derivative, is shown to be effective, in purified form, for the simultaneous extraction of trace levels of Cd(II), Co(II), Cu(II), Mn(II), Ni(II), Pb(II), and Zn(II) from natural waters into toluene. The high lipophilicity of the extractant and its chelates affords large preconcentration factors in a single batch-extraction. Back-extraction with a small volume of nitric acid provides additional enrichment for subsequent determination of total (soluble) metal by graphite-furnace atomic-absorption spectrometry (GFAAS). Calibration with standard solutions can be used, which has advantages over the method of standard additions.

Preconcentration of trace metals from acidic solutions by coprecipitation with dithizone

Traces of Ag, Bi, Cd, Cu, Hg, Pb, Pd and Zn are separated by carrier precipitation with dithizone from diluted HNO3 and HCl solutions. The separated trace elements are determined by flame AAS and/or by spectrophotometry. The preconcentration recovery is dependent on the acid concentration of the sample solution. The amount of dithizone precipitated is optimized. The detection limits (ng/ml) are 15.0 (Pb, Zn), 12.0 (Pd), 10.0 (Bi), 6.0 (Ag), 5.0 (Hg), 2.0 (Cu) and 1.0 (Cd). Aluminium, aluminium sulfate and gallium are analyzed with the method. The accuracy of the results was checked by differential pulse voltammetry.

Automation of trace-metal-clean column separation: Application to trace metal pre-concentration from seawater

Automation of trace-metal-clean column separation: Application to trace metal pre-concentration from seawater

Pre-concentration of trace metals from acidic sample solutions on a thin layer of activated carbon using dithizone as a chelating agent

Acidic sample solutions were analysed by flame AAS and spectrophotometry, making use of the collection of trace amounts of Ag, Bi, Cu, Cd, Hg, Pb and Zn as their dithizonates on a thin layer of activated carbon. The metal chelates were then released from the activated carbon layer by digestion with 14 M HNO3. The dependence of the trace element recoveries on the concentration of HNO3 and HCI in the sample solution was investigated. Water samples, aluminium, salts and acids were analysed and the accuracy of the results was checked by electrothermal AAS or by pre-concentration with a thiuram disulphide precipitate. The detection limits were between 0.3 ng ml–1(Cd) and 10 ng ml–1(Hg) and the relative standard deviations varied from 1 to 8%. The recovery, separation factor and pre-concentration factor of the method are discussed.

Determination of trace metals in an open ocean water reference material by inductively coupled plasma mass spectrometry

The remarkable detection power of inductively coupled plasma mass spectrometry (ICP-MS) was demonstrated by the analysis of an open ocean sea water reference material (with the acronym NASS-2). A 50-fold pre-concentration of several trace metals in the sea water was realised by their adsorption on to silica-immobilised 8-hydroxyquinoline, which separates the elements of interest from the bulk of the alkali and alkaline earth elements. The isotope dilution technique was used for the determination of seven elements (Ni, Cu, Zn, Mo, Cd, Pb and U). Accurate results were obtained for all of these elements except for Mo, with concentrations ranging between 0.027 and 11.5 µg l–1.

Preconcentration of trace metals from seawater with 7-dodecenyl-8-quinolinol-impregnated macroporous resin

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTPreconcentration of trace metals from seawater with 7-dodecenyl-8-quinolinol-impregnated macroporous resinKenji. Isshiki, Fumito. Tsuji, Tooru. Kuwamoto, and Eiichiro. NakayamaCite this: Anal. Chem. 1987, 59, 20, 2491–2495Publication Date (Print):October 15, 1987Publication History Published online1 May 2002Published inissue 15 October 1987https://doi.org/10.1021/ac00147a011RIGHTS & PERMISSIONSArticle Views226Altmetric-Citations64LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (649 KB) Get e-Alerts Get e-Alerts

Electrochemical preconcentration of metals using mercury film electrodes followed by electrothermal vaporization into an inductively coupled plasma and determination by atomic emission spectrometry.

The production and use of mercury film electrodes for matrix separation and preconcentration of trace metals from biological materials prior to their determination by inductively coupled plasma atomic emission spectrometry (ICP-AES) are described. Separation and preconcentration are achieved by controlled potential electrolysis on mercury-plated, glassy carbon electrodes. Electrodes with trace metal amalgam are transferred to an electrothermal vaporization device, the mercury is removed by evaporation, and the metals are then evaporated and determined simultaneously by ICP-AES. The method is applied to the determination of eight trace elements, Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn, in water solution and in the biological standard reference materials urine and bovine liver. The method precision varied between 3.8 and 8.1%.

Preconcentration of trace metals from salt solutions using thiuram disulphide as collector

Traces of Fe, Co, Ni, Cu, Zn, Cd and Pb in salt solutions (e.g. KCl, Ca(NO3)2, A12(SO4)3, Cr2(SO4)3, (NH4)2SO4) are determined by flame AAS after preconcentration with thiuram disulphide (TDS) as collector precipitate. The preconcentration recovery is mainly influenced by pH, TDS amount and its aging in the sample solution. Conditions of an optimal preconcentration procedure were elaborated. Detection limits vary from 0.5 ng/ml (for Cd) to 8.3 ng/ml (for Pb) and the relative standard deviation is 2 to 6 %. The accuracy of the results was checked by differential pulse anodic stripping voltammetry and by electrothermal AAS.

Electrochemical Preconcentration of Trace Metals for Simultaneous Multielement Determination by Inductively Coupled Plasma-Atomic Emission Spectrometry Utilizing Graphite-Cup Direct-Insertion Technique

Electrochemical preconcentration of trace metals on a graphite cup for multielement determination by inductively coupled plasma-atomic emission spectrometry (ICP-AES) is described, where controlled potential electrolysis of trace metals in an electrolyte solution similar to seawater has been examined by the use of a newly designed Teflon® cell to allow cathodic deposition. The characteristic of the present system is to make deposition of trace metals only inside a graphite cup, which is inserted into the plasma for the analysis by ICP-AES with the use of a computer-controlled graphite-cup direct-insertion technique. The electrolysis parameters and the solution circulation rates during electrolysis and washing of deposit have been optimized by a univariate search method. With the present experimental system, it is possible to preconcentrate trace metals by a factor of 30 to 300, and to separate them from the major matrix consituents, such as NaCl, KCl, and MgCl2, in artificial seawater. The detection limits for Cd, Co, Cr, Cu, Mn, Ni, Pb, and Zn at the pg/mL level can be obtained with relative standard deviation of 2 to 11%.

Pre-concentration of some trace metals from sea water on a mercapto-modified silica gel

Silica modified by the addition of mercapto chelating groups has been developed for the pre-concentration of trace metals from natural waters. This material removes cadmium, copper, lead and zinc from aqueous solution and can be employed for the pre-concentration of these metals by both column and batch techniques. Under column and batch conditions recoveries larger than 95% were common. For batch extractions of cadmium, zinc, copper and lead from sea water, recoveries of 91 ± 5, 98 ± 4, 97 ± 4 and 96 ± 5%, respectively, were obtained.

Preconcentration and determination of trace metals in synthetic sea water by flotation with inert organic collectors

The preconcentration and separation of copper, cadmium, cobalt and nickel 8-quinolinolates in solutions of high salinity including synthetic sea water is studied with phenolphthalein or 2-naphthol as collector and octadecylamine as surfactant. A simplex optimization is applied. Yields > 90% are achieved for Ni, Co and Cd with both collectors, but the copper yield is low. Flame atomic absorption spectrometry is used for the final measurements.

Simultaneous multi-element analysis for trace metals in sea water by inductively-coupled plasma/atomic emission spectrometry after batch preconcentration on a chelating resin

Batch treatment with Chelex-100 resin was investigated for preconcentration of trace metals in sea water followed by determination by inductively-coupled plasma atomic emission spectrometry. The preconcentration conditions such as resin weight, stirring time, and amount of ammonium acetate buffer solution were carefully examined for effective multi-element preconcentration from sea water. The resin weight could be decreased to 0.5 g (dry weight) for 1 l of sea water, which was much less than that required in the column method, and a preconcentration factor of 100 was achieved. Al, Ti, V, Mn, Fe, Co, Ni, Cu, Zn, Y, Mo, Cd and Pb in sea water were measured with good precision. The detection limits ranged from 6 to 180 ng l −1. The time required for one sample by the batch method was only 3 h.

Multielement-preconcentration for atomic spectroscopy by sorption of dithiocarbamate-metal complexes (e.g., HMDC) on cellulose collectors

The analytical preconcentration of trace metals from saline solutions by sorption of their dithiocarbamates on ‘reversed-phase’ cellulose is reported. Heavy metals [e.g., Bi, Cd, Co, Cr(III), Cu, Fe, Hg, In, Ni, Pb, Tl, Yb, Zn] dissolved at the ng/l to μg/l level can be quantitatively fixed as dithiocarbamates (e.g., HMDC) on cellulose within a few minutes. In salt solutions and without use of any carriermetal the distribution coefficients Kd are of the order 104 to 105 (ml/g) in the pH range between 4 and 10. The Kd values of dithiocarbamates on RP cellulose (e.g., acetylated cellulose) are higher by a factor of 5 to 10 than those on conventional RP sorbents (e.g., C18, C6H5). Moreover, the chemical blanks caused by the cellulose collector (batch and column procedure) are below the detection limits of the determination methods used (flame-AAS, graphite furnace-AAS, ICP-OES), Cu, Fe and Zn excepted. Combined with the above atomic spectroscopy methods, the multielement preconcentration with the aid of HMDC complexes is applied to the determination of trace metals in natural waters (including sea water), biological matters (e.g., urine, bovine liver) and high-purity metals (e.g., Al). The accuracy and precision of the developed analytical procedure are confirmed by trace determinations in standard reference materials (e.g., NBS 1577, Alusuisse 112/02).

The efficiency of cellix-p for the preconcentration of lead and other trace metals from waters

The cheating ion-exchanger Cellex-P, a cellulose phosphate ester, is shown to be effective for the preconcentration of Cu, Ni, Mn, Cd, Zn and Pb from water. The pH of the sample is not critical within the approximate range 5–8. The collected ions can be eluted efficiently in 10–25 ml of 1 M nitric acid from 2–16.5-cm columns of resin. Common salts present in natural waters do not interfere. Cellex-P is used for the preconcentration and determination of the metal ions in potable water by graphite-furnace atomic absorption spectrometry.