Ingrid Hagarova

The utilization of modified BCR three-step sequential extraction procedure for the fractionation of Cd, Cr, Cu, Ni, Pb and Zn in soil reference materials of different origins.

A modified three-step sequential extraction procedure for the fractionation of heavy metals, proposed by the Commission of the European Communities Bureau of Reference (BCR) has been applied to the Slovak reference materials of soils (soil orthic luvisols, soil rendzina and soil eutric cambisol), which represent pedologically different types of soils in Slovakia. Analyses were carried out by flame or electrothermal atomic absorption spectrometry (FAAS or ETAAS). The fractions extracted were: exchangeable (extraction step 1), reducible-iron/manganese oxides (extraction step 2), oxidizable-organic matter and sulfides (extraction step 3). The sum of the element contents in the three fractions plus aqua-regia extractable content of the residue was compared to the aqua-regia extractable content of the elements in the origin soils. The accuracy obtained by comparing the determined contents of the elements with certified values, using BCR CRM 701, certified for the extractable contents (mass fractions) of Cd, Cr, Cu, Ni, Pb and Zn in sediment following a modified BCR-three step sequential extraction procedure, was found to be satisfactory.

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 molybdenum in extracts of soil and sewage sludge crms after fractionation by means of bcr modified sequential extraction procedure

A modified three-step sequential extraction procedure proposed by the Commission of European Communities Bureau of Reference (BCR) was applied to certified reference materials of three different soil groups (rendzina, luvisol, and cambisol) and sewage sludge of different compositions originating from a municipal water treatment plant in order to assess potential mobility and the distribution of molybdenum in the resulting fractions. In the soils examined, molybdenum was present almost entirely in the mineral lattice, the content of molybdenum in the fractions of the studied reference materials of sludges was predominant in the fraction, represents Mo bound to organic matter and sulphide. The internal check of accuracy was performed on the results of the sequential extraction by comparing of the extractable amounts of molybdenum in the sequential procedure with the results of the pseudototal digestion of original samples. The recovery ranged from 96 to 101% and the precision (RSD) in the extracts was below 10%.

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%.

Bio-accumulation of As(III) and As(V) species from water samples by two strains of Aspergillus niger using hydride generation atomic absorption spectrometry.

The bio-accumulation ability of two strains of Aspergillus niger was studied in various synthetic media containing inorganic single-species As(III) and As(V) solutions and their admixtures and mining water with high As content in order to study the extent of bio-accumulation of the As species by the fungi. The AN1 A. niger strain, which served as a reference, was isolated from the Eutric Fluvisol soil (pH H2O/KCl 7.7/7.4) originating from an uncontaminated area near Gabčíkovo (Southwest Slovakia). The AN3 A. niger strain was isolated from the bottom sediment with a natural content of As 363 mg kg−1 (pH H2O/KCl 5.27/4.8) collected from the Blatina stream running from abandoned antimony mines near Pezinok (West Slovakia). Samples of fungi biomass following bio-accumulation experiments were acid-decomposed in an autoclave under elevated temperature and pressure and used for total inorganic arsenic (As) determination. After 24 h of bio-accumulation in a solution containing 10 µg L−1 As(III), the AN1 strain showed to be more efficient transforming 73% of As(III), in comparison with the AN3 strain by which 38% of As(III) was bio-transformed. On the other hand, the AN3 strain demonstrated greater capacity to retain in its mycelia 17% of As from a solution containing 10 µg L−1 As(V) as compared with less than 10% of As(V) accumulated in the mycelia of the AN1 strain. Continuous hydride generation atomic absorption spectrometry (HG-AAS) was used for simple, rapid, sensitive and accurate determinations of total inorganic As and As(III). The accuracy of the method for the determination of As(III) was evaluated by analysing spiked synthetic and natural river waters. Recoveries of 96–102% of spikes were obtained. Limits of detection (3σ-criterion) for total inorganic As determination and As(III) determination were 0.22 and 0.28 µg L−1, respectively.

Thallium fractionation in polluted environmental samples using a modified BCR three-step sequential extraction procedure and its determination by electrothermal atomic absorption spectrometry

Determination of thallium in polluted environmental samples and their extracts obtained by a modified BCR three-step sequential extraction procedure was used to study thallium distribution and mobility in the monitored polluted area affected by acidification (Šobov, Central Slovakia). The results of fractionation applied to 5 soil certified reference materials and 14 environmental samples show that the vast majority of thallium occurred in the residual fraction. This means that highly toxic thallium is strongly entrapped in the parent rock materials remains immobile and its environmental toxicity is therefore reduced. The limit of detection for thallium in the studied fractions was lower than 0.050 mg kg−1, the precision (RSD) of the ultratrace determination of thallium in the studied fractions was better than 17 % and the accuracy of the used method was verified by analyzing certified reference materials.

Cloud point extraction utilizable for separation and preconcentration of (ultra)trace elements in biological fluids before their determination by spectrometric methods: a brief review

This review summarizes and discusses applications related to the determination of (ultra)trace elements in biological fluids using cloud point extraction as sample pretreatment technique. Biological fluids, such as urine, whole blood, serum or plasma, are the most often analyzed biological materials in these applications. Spectrometric methods, such as flame atomic absorption spectrometry, electrothermal atomic absorption spectrometry, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry, are commonly used for quantification of elements preconcentrated by the extraction technique. Optimized extraction procedures lead to the high extraction recoveries of the target analytes. High enrichment factors achieved lead to the lowering of quantification limits. All these achievements illustrate the great potential of extractions for reliable quantification of (ultra)trace elements in complex biological matrix what is documented in this review of a number of works published on this topic.

Separation and quantification of metallic nanoparticles using cloud point extraction and spectrometric methods: a brief review of latest applications

Because of their unique physical and chemical properties, the use of metallic nanoparticles (MNPs) has considerably increased in various fields. This has led to a new concern about their presence in the environment. Since their negative effect and potential toxicity impact have been confirmed, scientists focus on the development of different procedures for their detection, identification, characterization and quantification, not only in homogeneous and simple matrices, but also in complex environmental matrices. The current review presents cloud point extractions recently developed and used for the separation/preconcentration of MNPs (such as Ag, Au, CuO, ZnO, and Fe3O4) before their spectrometric quantification. This combination has been shown as a promising alternative for separation/preconcentration and quantification of MNPs in different environmental waters (such as tap, canal, mineral, bottled, lake, river, sea waters, or treated and untreated wastewaters) and some antibacterial products. The reviewed separation procedures have illustrated not only the separation of MNPs from the matrix, but also the separation of MNPs from their metallic ions. After optimization, high preconcentration factors and quantitative recoveries were described in most cases.