Zs. Horváth

On-line preconcentration and determination of trace elements by flow injection-inductively coupled plasma atomic emission spectrometry

Abstract A study was made of the capabilities of iminodiacetic acid/ethylcellulose (IDAEC) to serve as the chelating resin for preconcentrating trace elements together with a computer-assisted on-line flow injection analysis-inductively coupled plasma atomic emission spectrometry technique. The system was tested with a few analytes of particular clinical and environmental importance (Cd, Co, Cu and Pb) in matrices such as water, sea water and urine. The performance of IDAEC resin was compared with that of carboxymethylated polyethyleneimine-polymethylenepolyphenylene isocyanate (CPPI) and Chelex 100 with regard to enrichment factor, analytical throughput and recovery. With several obvious advantages over the batch procedure, the on-line mode improved the detection power by one to two orders of magnitude and allowed twelve samples per hour to be treated. IDAEC appears to be the most convenient resin in terms of efficiency and long-term performance.

Use of a new type of 8-hydroxyquinoline-5-sulphonic acid cellulose (sulphoxine cellulose) for the preconcentration of trace metals from highly mineralised water prior their GFAAS determination

Sulphoxine cellulose microcolumn was used in an FI-GFAAS system for the preconcentration of trace metals, Cd, Co, Ni, Pb and V from water and from highly mineralised water and also in the presence of complexing agent, e.g. citrate. The recovery was quantitative at pH 5 for all of the elements from NIST 1643c trace elements in water SRM and from highly mineralised water samples. No significant difference was found in the sorption of V(IV) and V(V) during preconcentration. The preparation of the 8-hydroxyquinoline-5-sulphonic acid cellulose (sulphoxine-cellulose) by Mannich reaction from aminoethyl cellulose or via chlorodeoxy and ethylenediamine cellulose is also described.

Breakdown of organic mercury compounds by hydrochloric acid-permanganate or bromine monochloride solution for the determination of mercury by cold-vapour atomic absorption spectrometry

Abstract Hydrochloric acid—potassium permanganate and bromine monochloride are examined for the decomposition of methylmercury(II) chloride, Ceresan, phenylmercury(II) borate and thiomersal added to waters. Both procedures give quantitative recovery of mercury. Bromine monochloride has many advantages: blanks are low, the limit of detection (3σ) is 0.06 μg Hg l −1, routine work is simplified because only two reagents are needed and the reaction time is 5–10 min. The reagent also acts as a preservative. Common contaminants (chloride, bromide, sulphide, alcohols, benzene) do not interfere.

Determination of trace metals and speciation of chromium ions in atmospheric precipitation by ICP-AES and GFAAS

Sampling and analytical techniques used for determining trace metal concentrations in atmospheric precipitation waters collected in Hungary are presented. The results of the analyses are briefly discussed and special attention is devoted to chromium speciation. For the preconcentration of the trace metals a chelating cellulose, iminodiacetic acid ethylcellulose (IDAEC) microcolumn was used in a flow-injected system. Cd, Co, Cu, Fe, Mn, Ni, Pb, Ti, V and Zn were determined by ICP-AES. In precipitation water the concentrations of the trace elements were in the 0.1-50 mug/l. range. The two forms of chromium, Cr(III) and Cr(VI) were separated using IDAEC and the anion exchanger diethylamine ethylcellulose, respectively. Cr was determined by GFAAS. In atmospheric precipitation the concentration of Cr(III) was in the range of 0.1-0.4 mug/l. while that of Cr(VI) in the range of 0.04-0.1 mug/l.

Imino-diacetic-acid-ethyl-cellulose and its chelate forming behaviour—I

Imino-diacetic-acid-ethyl-cellulose (IDE-cellulose) has been prepared by a heterogeneous phase procedure from amino-ethyl-cellulose with chloroacetic acid. The resulting product has been characterized by its i.r. spectrum, by the N/COOH ratio and by the acidity constants computed from potentiometric titration curves. Values of the acidity constants are: pK1 = 2·65 ± 0·08, pK2 = 9·1 ± 0·2 at 20°C and in 1 M NaClO4. The chelating ability of IDE-cellulose have been studied potentiometrically. The relative stabilities of the metal chelates decrease in the order Cu(II) > Ni(II) > Zn(II) ≧ Co(II) ⪢ Ca(II), Mg(II).

Iminodiacetic acid/ethylcellulose as a chelating ion exchanger : Part 1. Determination of trace metals by atomic absorption spectrometry and collection of uranium

Abstract A chelate-forming ion exchanger, iminodiacetic acid/ethylcellulose, is used for the separation of trace metals from waters and different organic solvents. Added uranium was collected from sea waters with recoveries of about 97%. Graphite-furnace atomic absorption spectrometry and solution spectrophotometry were used to quantify the metals. For the direct determination of trace metals in waters by the graphite-furnace method, a simple matrix-matching method is described. The detection limit for cadmium was 0.1 μg l−1 and for lead 1 μg−1 in drinking water.

Puriwat® apparatus : A system of ion-exchange celluloses for the production of high-purity water☆

Abstract PURIWAT apparatus produces high-purity water for special purposes from distilled or deionized water. Contaminants at the parts per million level can be removed by passing the water through a column of sandwiched ion-exchange cellulose as filtering media. The volume of water to be purified can be programmed and the apparatus operates without supervision. The filtering media is disposable, and fillings for the purification of 50 or 100 l of water are available. The output of high-purity water is up to 6 l/h. When analysed by neutron activation analysis, the purified water is especially low in copper (0.0025 ppb 1 ), while the contents of other heavy metals are less than 0.01 ppb.

The role of spectrochemical analysis in the determination of the composition of atmospheric precipitation and aerosol samples in remote environments

Abstract In recent years there has been an increased interest in trace metals in atmospheric precipitation and air and their environmental effects. In estimating pollution it is necessary to know the background concentrations of the heavy metals as measured in remote areas far from human activities. From this standpoint spectroanalytical methods cover a wide range of concentrations and are unique in their ability to determine the composition of precipitation and aerosol samples, including toxic trace metals. In the present study determinations of major, minor, and trace metals were performed by ICP-AES and GFAAS. Microwave digestion and flow-injection enrichment methods were designed for this purpose. From the experimental data background levels of metals in atmospheric precipitation and air at a remote location in Hungary were ascertained.