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1

Ekstrakcja sekwencyjna metali z próbek środowiskowych

Kalembkiewicz J., Sočo E.

Wiadomości Chemiczne

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2005

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[Z] 59, 7-8

697--721

EN

The metals contribution in food chain: soil - plant- animal - man and influence of metals on the course of biochemical reactions in the environment depends among others on possibility of its transfer from sample to solutions. In practice mobility process of metals is investigated by performance of the sequential extraction of sample. The metals sequential extraction for a given sample depend among others on the type of sample, leaching reagent, conditions of the process, the initial condition of sample (environmental sample, air-dried sample) and chemical forms of metals presents in sample. Most often the studies evaluate the chemical fraction of metals in environmental sample as: exchangeable, carbonate, oxide, organic, sulfide and residue forms. Many procedures of sequential extraction of sample e.g. soil, bottom sediments and fly ash were described, which include group extraction of metals to solution. Applied procedures of sequential extraction concern of group extraction of metals and doesn't selective for individual metals. Therefore, we have attempted to establish optimum conditions for researches of individual chemical fraction of metals in sample by sequential extraction method. Chemical fraction described as mobility in environmental conditions are frequently research in first and second step of sequential extraction. Next researches fractions of metals are mobile in environmental in specific conditions. Among various methods of the sequential extraction, the Tessier, Rudd, BCR, Gatehouse, Kersten and Forstner, Psenner and Sposito procedures are most often used for environmental samples. The procedures sequential extraction of environmental samples, defined metals fraction and list of researches metals in sample are shown in Table 1. Analysis of chemical fraction of metals depends on quantity of steps method, strong of reagents and conditions of researches.

2

Rozdział i oznaczanie Cr(III) i Cr(VI) w próbkach środowiskowych

Kalembkiewicz J., Sočo E.

Wiadomości Chemiczne

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2002

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[Z] 56, 9-10

855-873

EN

Learning the biochemical properties of Cr(III) and Cr(VI), especially mutagenic activity of Cr(VI) caused quick development of investigation of Cr speciation in environmental samples. Complex composition of matrix, possible course of the redox reaction of Cr and its low concentration often make difficult application of direct methods of determination of Cr(III) and Cr(VI). The investigation of speciation of Cr by preliminary separation of Cr(III) and Cr(VI) and their preconcentration eliminates a series of analytical problems and creates a possibility of Cr detection with various techniques, also in coupled systems. The Cr(III) and Cr(VI) in systems HPLC-ICP-AES, HPLC-ICP-MS, HPLC-AAS, HPLC-FI-AAS, HPLC-UV were separated, preconcetrated and determined. Independently from HPLC also other chromatographic techniques were used. Ion-exchange was applied mainly to separation of Cr(III) and Cr(VI), as well as to separation of Cr(VI) or Cr(III) [58] from other ions. To separation of Cr(III) and Cr(VI) there were applied: sorption, biopolymer coating and bioaccumulation. Separation and preconcentration of Cr(III) and Cr(VI) is possible by applying solvent extraction. To extraction of Cr(III) and Cr(VI) and their separation were applied amines, ammonium salts and non-ammonium salts, amine oxides, carboxylic and hydroxycarboxylic acids and other reagents. To separation and preconcentration of Cr(III) and Cr(VI) there are proposed ion-exchange membrane, electrophoresis, precipitation and co-precipitation and other methods of separation. Determination of Cr(III) and Cr(VI) without preliminary separation is possible in environmental samples, in which at the stage of preparing to analysis or during analysis the redox reactions with participation of Cr do not proceed. For direct determination of Cr(VI) spectrophotometric method (UV) is applied with the use of 1,5-diphenylcarbazide, methylene blue, iodonitrotetrazolium chloride, tetrazolium violet , 5-Br-PADAP, dibenzyl-dithiocarbamate, rhodamine 6G, nitrotetrazolium blue and neotetrazolium chloride, whereas for determination of Cr(III) there were applied: EDTA, triphenylmethane reagents, PAR and PAN. For direct determination of Cr(VI) or Cr(III) polarography and others methods were applied.

3

Separation of Cr(IV) from soil extracts

Kalembkiewicz J., Kopacz S., Sočo E.

Chemia Analityczna

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2001

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Vol. 46, No. 3

369-376

EN

The conditions for the extraction of Cr(VI) from soil eluates were established. The soil eluates were obtained by sequential extraction of soil with MgCl(2)a and CH(3)COOH/CH(3)COO Na solutions. The optimum of extraction was studied in function, of pH, kind of extracting solvent, its concentration, time and multiplicity of extraction. The optimum conditions for Cr(VI) extraction and speciation of Cr(VI) and Cr(III) were established.

PL

Wykonano badania ekstrakcyjnego wydzielania Cr(VI) z eluatów gleby po ekstrakcji sekwencyjnej roztworami MgCl(2) i CH(3)COOH/CH(3)COONa. Badano wpływ pH, rodzaju rozpuszczalnika organicznego i jego stężenia oraz czasu i wielokrotności ekstrakcji na wydzielanie Cr(VI). Ustalono optymalne warunki wydzielania Cr(VI) oraz prowadzenia specjacji Cr(VI) i Cr(III) w tych roztworach.