Marcin Siepak

Comparison of modifiers for determination of arsenic, antimony and selenium by atomic absorption spectrometry with atomization in graphite tube or hydride generation and in-situ preconcentration in graphite tube

The study was performed to compare the effect of magnesium modifier (magnesium nitrate) with that of other modifiers (palladium nitrate and nickel nitrate) in determination of arsenic, antimony and selenium by atomic absorption spectroscopy with atomization in a graphite tube, with generation of hydrides and in situ preconcentration in a graphite tube. The assumed criterion of a modifier performance was the magnitude of the analytical signal. It was found that in determinations with atomization in a graphite furnace the effects of all these modifiers were comparable, while in those with hydride generation and in situ preconcentration in a graphite tube the magnesium modifier showed poorer performance (25% decrease of the analytical signal). In determinations of arsenic and selenium the analytical signal obtained with magnesium salt as a modifier was comparable with those obtained in the presence of all other modifiers.

Thallium in fractions of sediments formed during the 2004 tsunami in Thailand.

Thallium is a highly toxic element. Its concentration in sediment fractions from the 2004 tsunami in Thailand was investigated. A modified BCR procedure was used for sequential extraction. Tl was determined by flow injection differential pulse anodic stripping voltammetry. It was found that the majority of thallium in the investigated tsunami sediments (86-97 percent) is entrapped in the alumosilicate parent matter i.e. it is entirely immovable. Only the total destruction of this residual fraction with hydrofluoric acid made this thallium available. The conclusion strongly supports the hypothesis that thallium is mainly entrapped in alumosilicate parent matter. Total thallium concentration in the investigated tsunami sediments was divergent in various samples from 0.37 to 1.13 μg g(-1) and significantly different from the reference area (0.05 μg g(-1)). Tsunami sediment fractions from different sampling points are divergent in terms of total thallium concentration and concentration of mobile thallium. Generally, mobile thallium concentration was growing in sequence: water soluble fraction<exchangeable fraction<reducible fraction<oxidizable fraction. However, in two samples, thallium concentration in the reducible fraction was higher than in the oxidizable fraction.

Determination of Sb(III) and Sb(V) in Water Samples by Hydride Generation Atomic Absorption Spectrometry with In-Situ Trapping in a Graphite Tube

Abstract This work presents results of determinations of inorganic Sb(III)/Sb(V) species and total content of antimony in water samples by the method of atomic absorption spectrometry with hydride generation and in-situ concentration in a graphite tube. The achieved determination limit (3σ) was 0.014 ng/mL for determination of Sb(III) species and the total content of antimony. Moreover, the paper reports results of antimony determination in samples of mineral and tap water obtained by the method with the analyte concentration on the atomizer (graphite tube) surface. The content of antimony in the samples studied varied in the range from 0.04 ng/mL to 0.44 ng/mL for Sb(III) and from 0.22 ng/mL to 0.62 ng/mL for Sb(V).

Heavy metals in fluvial sediments of the Odra River flood plains - introductory research

Heavy metals in fluvial sediments of the Odra River flood plains - introductory research The article presents the results of research on concentrations of heavy metals (Cd, Cr, Cu, Ni, Pb and Zn) in fluvial sediment samples collected in the flood plains of the Odra River. The samples were collected from the presently flooded area and from the area which was formerly flooded. The extraction of sediment samples was conducted using aqua regia and four other extractants: 0.01M CaCl2, 0.1M HCl, 0.005M DTPA and 0.02M EDTA. The analysis of the results revealed different concentration values for particular sample collection sites situated along the course of the Odra River. The differentiation of metal concentrations in the investigated samples depending on the extractants was also observed. The concentrations of metals were determined using the technique of atomic absorption spectrometry with flame atomization (F-AAS).

Speciation analysis of inorganic form of arsenic in ground water samples by hydride generation atomic absorption spectrometry with insitu trapping in graphite tube

This paper presents the results of a study on the optimization of the determination of total arsenic and its species using the absorption atomic spectrometry method combined with hydride generation and in-situ concentration on the inner walls of the graphite tube. To ensure a maximum efficiency of the in-situ analyte concentration on the graphite tube walls, a palladium modifier subjected to preliminary thermal reduction was used. The limits of detection (3σ) were 0.019 ng/mL for total As and 0.031 ng/mL for As(III) at the preliminary analyte concentration for 60s. The optimised procedure of the analyte concentration on the inner walls of the atomiser (graphite tube) was applied for determinations of arsenic in samples of ground water. The content of arsenic in the samples studied varied from 0.21 ng/mL to 0.80 ng/mL for As(III), and from 0.19 ng/mL to 1.24 ng/mL for As(V).

Determination of inorganic arsenic species As(III) and As(V) by high performance liquid chromatography with hydride generation atomic absorption spectrometry detection

The paper presents the principles and advantages of a technique combining high performance liquid chromatography and hydride generation atomic absorption spectrometry (HPLC-HGAAS) applied to speciation analysis of inorganic species of arsenic As(III) and As(V) in ground water samples. With separation of the arsenic species on an ion-exchange column in the chromatographic system and their detection by the hydride generation atomic absorption spectrometry, the separation of the analytical signals of the arsenic species was excellent at the limits of determination of 1.5 ng/ml As(III) and 2.2 ng/ml As(V) and RSD of 4.3% and 7.8% for the concentration of 25 ng/ml. The hyphenated technique has been applied for determination of arsenic in polluted ground water in the course of the study on migration of micropollutants. For total arsenic concentration two independent methods: HGICP-OES and HGAAS were used for comparison of results of real samples analysis.

Hydride generation atomic absorption spectrometry with insitu graphite tube trapping for the determination of Se (IV) and Se (VI) in baltic sea water samples

This paper reports the results of an optimisation study for a procedure to determine the total selenium and its inorganic species, Se(IV) and Se(VI) using atomic absorption spectrometry combined with hydride generation and in-situ trapping of the analyte on the inner walls of the graphite tube. With the use of the proposed modification, a detection limit (3σ) of 0.018 ng/ml is achieved. This paper presents exemplary results, according to the proposed procedure, for selenium determination in samples of marine water. The concentrations of selenium in the samples ranged from <0.02 ng/ml to 0.16ng/ml of Se(IV) and from <0.02 ng/ml to 0.10 ng/ml of Se(VI).

Distribution of heavy metals in the Mała Wełna River system (western Poland)

Distribution of heavy metals in the Mała Wełna River system (western Poland) This paper reports the results of measurements of heavy metal concentrations in water, suspension, and bottom sediment samples collected at eight sites along the Mała Wełna River (western Poland). The samples were collected once a month from May to August 2006. The highest variations in the water of the Mała Wełna River were noted in the concentrations of Zn, Pb, and Cu. The results indicate that the suspension plays an important role in the transportation of pollutants contaminating the water and later in the accumulation of pollutants in the bottom sediments. The concentration of heavy metals in the bottom sediments were determined individually in grain size fractions: >2, 2-1, 1-0.5, 0.5-0.25, 0.25-0.1, 0.1-0.063, <0.063 mm. Concentrations of them were the lowest in the 0.5-0.25 and 0.25-0.1 mm fractions, and were the highest in the 0.1-0.063 and <0.063 fractions.

Physico-Chemical Parameters Determining the Variability of Actually and Potentially Available Fractions of Heavy Metals in Fluvial Sediments of the Middle Odra River

Abstract The occurrence of heavy metals (Cd, Cr, Cu, Ni, Pb, Zn) has been determined in the fluvial sediment samples collected along three transects in the Middle Odra River (western Poland) with a width of 360 m. The total concentrations of the metals were obtained after HNO3 microwave digestion and the available fractions of heavy metals were determined by single extraction procedures using two extractants: 0.01M CaCl2 and 0.05M EDTA. The measurement of physico-chemical parameters was also performed. The determination of total and available fractions of heavy metals, except potential available fractions of Cr, revealed high concentrations of studied elements detected in the sediment samples characterized by high content of coarse and very coarse-grained sand fraction and high content of organic matter. It was found that the concentrations of total and available fractions of metals could increase along with the content of organic matter, Eh values and concentrations of H+. Apart from the above, those concentrations become the lowest, the higher the content of medium grain size fractions is. Furthermore, the amounts of CaCl2 and EDTA extractable metals increase in the sediments samples characterized by the lowest total and available concentrations of heavy metals.

Tracking heavy metal contamination in a complex river-oxbow lake system: Middle Odra Valley, Germany/Poland

Oxbow lakes have received much attention in recent years due to their ecological importance and vulnerability for contamination. Sediment cores collected from the floor of oxbow lakes indicate the increasing contamination of lakes with heavy metals (Cu, Cd, Pb, Zn, Ni, Cr) over the last fifty years, owing to the development of transport and industry. Little is known, however, about how various factors can enhance or impede the migration of metallic contaminants between the pollution source and lake ecosystems. To untangle these complex processes, the metal distribution was studied throughout the waters and sediments of an urban zone-river-oxbow lake system in the Middle Odra Valley, Germany/Poland. As expected the degree of metal contamination is highest (>10 enrichment) at low distance (<1km) from the human source of pollution. Using correlations with highly mobile in water Na+ and Cl- ions, we reveal, however, that due to hydrological factors some metals (Cu, Cd, and Pb) are up to >5 times enriched in the sediments of lakes even >10km distant from the nearest source of pollution. The lakes that are permanently connected with the Odra River or that are frequently flooded are most vulnerable for contamination. Although the metal concentrations are especially enriched in the smallest grain size fractions, this portion of metals seems to be less bioavailable with respect to that accumulated within the larger grain size fractions. Concentrations of metallic contaminants in the bottom sediments of the Middle Odra lakes are generally lower than in other oxbow lakes. Having untangled the variety of processes controlling metal migration in a complex river-oxbow lake system operating on these low metal concentrations, allows us to believe that our approach could become a paradigm for future trace element studies in a variety of similar lowland systems across the World.