Jana Kubová

Utilization of optimized BCR three-step sequential and dilute HCl single extraction procedures for soil-plant metal transfer predictions in contaminated lands.

The prediction of soil metal phytoavailability using the chemical extractions is a conventional approach routinely used in soil testing. The adequacy of such soil tests for this purpose is commonly assessed through a comparison of extraction results with metal contents in relevant plants. In this work, the fractions of selected risk metals (Al, As, Cd, Cu, Fe, Mn, Ni, Pb, Zn) that can be taken up by various plants were obtained by optimized BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and by single 0.5 mol L(-1) HCl extraction. These procedures were validated using five soil and sediment reference materials (SRM 2710, SRM 2711, CRM 483, CRM 701, SRM RTH 912) and applied to significantly different acidified soils for the fractionation of studied metals. The new indicative values of Al, Cd, Cu, Fe, Mn, P, Pb and Zn fractional concentrations for these reference materials were obtained by the dilute HCl single extraction. The influence of various soil genesis, content of essential elements (Ca, Mg, K, P) and different anthropogenic sources of acidification on extraction yields of individual risk metal fractions was investigated. The concentrations of studied elements were determined by atomic spectrometry methods (flame, graphite furnace and hydride generation atomic absorption spectrometry and inductively coupled plasma optical emission spectrometry). It can be concluded that the data of extraction yields from first BCR SEP acid extractable step and soil-plant transfer coefficients can be applied to the prediction of qualitative mobility of selected risk metals in different soil systems.

Determination of lead and cadmium in human hair by atomic absorption spectrometric procedures after solid phase extraction

Abstract A separation and preconcentration procedure for Pb and Cd in human hair by using the chelating ion-exchanger, Iontosorb-Oxin, is described. The sorption yield dependence of Pb and Cd, on pH, time, and on the presence of accompanying elements, was investigated. The hair samples were decomposed by microwave irradiation and the determination of lead and cadmium was by flame and electrothermal atomic absorption spectrometry (F-AAS and ETA-AAS, respectively). The precision and accuracy of this procedure were checked by the use of synthetic and certified reference materials. The limit of determination was 1 μg Pb l −1 and 0.1 μg Cd l −1 , respectively. The procedure was applied to samples of human hair.

Free aluminium extraction from various reference materials and acid soils with relation to plant availability

The single extractions with 15 extractants (agents) (H(2)O, KCl, NH(4)Cl, NH(4)F, CaCl(2), BaCl(2), CuCl(2), LaCl(3), Na(2)S(2)O(4), (NH(4))(2)C(2)O(4), Na(4)P(2)O(7), NTA, EDTA, DTPA, HCl), the optimised BCR (Community Bureau of Reference) three-step sequential extraction procedure (SEP) and the solid phase extraction (SPE) by the chelating ion-exchanger Iontosorb Salicyl (cellulose resin containing covalently bound salicylic acid functional groups) were used for the partitioning of Al in very acid soil samples taken from an area influenced by acid mine solutions. The precision, accuracy and repeatibility for all steps of the optimised BCR SEP were checked on the various reference materials (CRM 483 sewage sludge amended soil, CRM BCR 701 freshwater sediment, SRM 2710 and SRM 2711 Montana soils). Also the new indicative values of the optimised BCR SEP fractional Al concentrations were obtained for these reference materials. The aluminium amounts obtained by the used extraction procedures were valuated and discussed from the aspect of the Al concentration in the plants (grass) growing on the same studied soils. The aluminium toxicity indexes (ATI) calculated for the studied soils, the BaCl(2) and acetic acid soil extracts and the grass stems and roots were used for the assessment of the Al toxicity to the plants. The ATI value was defined as the ratio of the nutrient cations (Ca, Mg, K, Na) concentration sum to the Al concentration. The flame atomic absorption spectrometry (LOQ=0.2mgl(-1)) and the inductively coupled plasma optical emission spectrometry (LOQ=0.03mgl(-1)) were used for the aluminium quantification.

Spectrographic determination of gold in geological materials after preconcentration on Spheron-Thiol

Abstract A spectrographic method for the determination of gold in geological materials after preconcentration on chelating sorbent Spheron-Thiol has been developed. The method involves the decomposition of the samples, preconcentration of Au on Spheron-Thiol, decomposition of the sorbent and spectrographic determination of gold at 267.59 nm. The method is simple, rapid and enables the determination of gold at μg g −1 levels in various types of geological materials with good precision and accuracy. The detection limit is 0.5 μg Au kg −1 . The method has been applied to the determination of Au in a number of certified and other reference materials with accurate results.

Determination of rare earth elements in mineral waters by inductively coupled plasma atomic emission spectrometry

A procedure for selective preconcentration of all rare earth elements (REE) in mineral waters on a Dowex cation exchanger has been developed. The precision and accuracy of the procedure were checked on a synthetic standard solution, as well as on real samples using inductively coupled plasma atomic emission spectrometry (ICP-AES). The efficiency of the preconcentration procedure was checked by recovery tests and the reliability of the ICP-AES determination of REE established by comparing the results obtained with those from spectrophotometric analysis.

Determination of beryllium trace contents in mineral waters after preconcentration on a chelating ion-exchanger

SummaryA separation-preconcentration procedure for the determination of Be traces in mineral waters is described. The precision and the accuracy of the procedure were checked by the use of artificial as well as of real samples by AAS-ETA and AES-ICP. On the basis of the results and of their statistical evaluation, the proposed procedure allows to obtain reliable results with the necessary limit of determination and can provide important, till now not accessible information on Be-concentration in waters.

Comparison of element levels in minimal and complex yeast media

The cellular functions are strongly influenced by the composition of the environment. In particular, phenotypes of microbial strains are modulated by concentrations of ions in the culture medium, and differences in element levels may be responsible for a phenotypic variability observed when microbial strains are grown on synthetic versus complex media. In this report, we analyzed the levels of nine elements (magnesium, potassium, sodium, calcium, iron, copper, manganese, zinc, and phosphorus) and sulphate ions in commercially available peptone and yeast extract and compared them with those in yeast nitrogen base routinely used for preparation of synthetic minimal media. We observed that whereas some elements are present at similar levels, the levels of others differ by a factor as high as 20. The observed differences should be taken into account when interpreting different phenotypes observed for microbial strains grown on synthetic versus complex media.

Determination of trace amounts of total dissolved cationic aluminium species in environmental samples by solid phase extraction using nanometer-sized titanium dioxide and atomic spectrometry techniques

Nanometer-sized titanium dioxide was used as a solid-phase extractant for the separation and preconcentration of trace amounts of Al(III) prior to its determination by electrothermal atomic absorption spectrometry (ET AAS) and inductively coupled plasma optical emission spectrometry (ICP OES). The optimal conditions for the proposed solid phase extraction (SPE; 50mg TiO(2), 10 min extraction time, pH 6.0, HCl and HNO(3) as eluents) and ET AAS measurement (1500 degrees C pyrolysis and 2600 degrees C atomization temperatures, Mg(NO(3))(2) as matrix modifier) were obtained. The adsorption capacity of TiO(2) was 4.1mg Al g(-1) TiO(2). Two modes of the proposed procedure were compared, (I) batch and elution mode with the elution of Al from TiO(2) phase by nitric or hydrochloric acid, and (II) batch and slurry mode (without elution) with the direct TiO(2) phase-slurry sampling. Finally, the batch and slurry mode of nanometer-sized TiO(2) SPE with slurry ET AAS detection and quantification was preferred and used for the determination of trace amounts of total dissolved cationic Al species in synthetic and natural water samples. The method accuracy was checked by the analysis of lake water CRM TMDA-61 and by the technique of analyte addition (sample spiking). Under the optimal conditions, the calibration curve for batch and slurry TiO(2) SPE with a 10-fold preconcentration was linear up to 40 microg L(-1) Al. The limit of detection (LOD) and the limit of quantification (LOQ) was 0.11 microg L(-1) Al and 0.35 microg L(-1) Al, respectively, with a preconcentration factor of 20 and a relative standard deviation (RSD) lower than 5%.

Application of thermodynamics in a specific force field to the adsorption of Al3+ ions on the chelating resins Ostsorb Oxin, Ostsorb Salicyl, Spheron Oxin, and Spheron Salicyl: Mathematical analysis of sorption isotherms using nonlinear mean square software

Abstract The sorption mechanism of Al 3+ on chelating resins by means of mathematical analysis of sorption isotherms using nonlinear mean square software was studied. This method should yield more detailed information than classical thermodynamics and should be more flexible than the statistical–mechanical method, so that it would make it possible to obtain fairly easily relations directly applicable in practice. This model defined the specific potential Φ Al R for the ion in a resin (which depends on properties of resin and ion). On the basis of this model, N and PO isotherms were derived. To study the sorption mechanism, the Freundlich, Langmuir, N and PO equations (models) of isotherms were used. It was estimated that the functional groups (8-hydroxyquinoline and salicylate) in the studied chelating resins influence Φ Al R and thus their mechanism and sorption capacity.

Atomic absorption spectrometric determination of ultra-trace amounts of mercury in waters

A sorption method using the chelating ion exchanger Spheron Thiol was developed for the preconcentration of mercury. To avoid a complicated and problematic desorption, direct atomic absorption spectrometric determination of mercury in the solid sorbent by the use of a TMA-254 spectrometer (trace mercury analyser) was applied. The limit of determination was 0.2 ng l–1 using 1000 ml of water and 0.1 g of Spheron Thiol. The precision of the method expressed as relative standard deviation was 10%. The accuracy of the method was checked by the standard additions technique. The method was applied to the determination of mercury in different types of waters.