Preliminary exploration of direct mercury speciation in solid samples by using thermal release coupled to electrothermal atomic absorption spectrometry.

It is known that monitoring of mercury and notably its species is very important to assess their impact and distribution in the environment. In this regard, the development of a methodology for mercury speciation in natural and man-made media is of particular importance. There are a variety of studies in this area associated with the application of thermal release in combination with electrothermal atomic absorption detection for direct mercury speciation in solid samples without preliminary extraction of analytes.

Metal-organic framework application for mercury speciation using solid phase extraction followed by direct thermal release-electrothermal atomization atomic absorption spectrophotometric detection (ETA AAS).

Metal-organic frameworks (MOFs) are increasingly used in analytical chemistry for pre-concentration of trace elements followed by their determination using modern analytical techniques. However, there are a limited number of publications concerning the use of MOFs for speciation purposes, while their structural and functional features are perspective for the element species selective extraction and pre-concentration. It is known that mercury refers to the most hazardous elements which species demonstrate different toxicity, migration routes and bioavailability as well.

Capillary zone electrophoresis as a simple approach for the study of p-arsanilic acid transformation in the process of photolytic degradation.

Arsenic aromatic compounds including p-arsanylic acid (pASA) are still widely used in a number of countries as the feed additives in animal breeding resulting in its entering the environment. Under the influence of oxidizing agents or UV radiation, pASA undergoes transformations leading to generation of inorganic arsenic species that are more mobile and toxic than organic ones. On the one hand, an approach based on the treatment of contaminated waters by UV irradiation seems perspective for their detoxification, but the feasibility of this approach depends on the composition of the products forming as a result of photodegradation.

Rh(III) hydroxocomplexes speciation using HPLC-ESI-MS.

A mixture of rhodium(iii) hydroxocomplexes formed during the polycondensation process in alkaline media has been fully characterized by the hyphenated high performance liquid chromatography with electrospray ionization mass spectrometry (HPLC-ESI-MS). The baseline separation was achieved using reverse phase ion-pair chromatography (RP-IP-HPLC) in gradient elution mode. When using SDS as the ion pair, the formation of all types of its associates with the molecules of acetonitrile, as well as oligomers of rhodium aquahydroxocomplexes, etc.

The study of Rh(iii) hydroxocomplexes using capillary zone electrophoresis with a UV-Vis detector: the development of the method.

The expediency of capillary zone electrophoresis application in the study of a mixture of rhodium(iii) hydroxocomplexes is shown for the species formed during the thermal treatment of [Rh(OH)] at 60 °C in alkaline media. As these compounds are unstable in solution because of polycondensation at pH > 10 and the formation of insoluble rhodium(iii) hydroxides at pH 5-10, their acidic derivatives with terminal aqua ligands acted as the objects of the study. Optimal separation conditions were achieved using sodium perchlorate as a background electrolyte, a voltage of +20 kV and pH 2.

Mechanisms of low-temperature vapor-gas streams formation from sulfide mine waste.

This paper presents experimental data that revealed the potential for chemical element transport by low-temperature vapor-gas streams. The study was conducted on sulfide waste heap sites located in the Kemerovo region, Russia. Condensates of vapor-gas streams were collected and analyzed in the air above the waste heaps and during laboratory experiments using samplers specially designed for this purpose.

Near-UV photooxidation of As(III) by iron species in the presence of fulvic acid.

Photooxidation of As(III) in ternary As(III) - Fe(III) - Fulvic acid system at pH 4 was investigated by optical spectroscopy, steady-state photolysis (365 nm) and atomic-emission spectrometry with inductively coupled plasma techniques. It was found that at all values of [FA]/[Fe] ratio the main photoactive species is OH radical formed by photolysis of Fe(III) hydroxocomplexes. Addition of fulvic acid leads to mainly negative effect on As(III) photooxidation due to the following reasons: (i) slow dark reduction of photoactive Fe(III) species with formation of scattering particles and photoinert Fe(II) species; (ii) formation of photoreductive Fe(III)-FA complexes incapable to oxidize As(III), (iii) competition of both FA and Fe(III)-FA complexes for UVA quanta with FeOH complex and for OH radicals with As(III).

Phytoremediation-biorefinery tandem for effective clean-up of metal contaminated soil and biomass valorisation.

During the last few decades, phytoremediation process has attracted much attention because of the growing concerns about the deteriorating quality of soil caused by anthropogenic activities. Here, a tandem phytoremediation/biorefinery process was proposed as a way to turn phytoremediation into a viable commercial method by producing valuable chemicals in addition to cleaned soil. Two agricultural plants (Sinapis alba and Helianthus annuus) were grown in moderately contaminated soil with ca.

Phytoextraction of trace elements by water hyacinth in contaminated area of gold mine tailing.

The ability of water hyacinth (Eichhornia crassipes) to uptake Ag, Ba, Cd, Mo, and Pb from waters in gold mine tailing area was studied. All experiments were carried out in the field conditions without using of model system. Bioconcentration (BCF) and translocation factors (TF) as well as elements accumulation by plant in different points of tailings-impacted area were evaluated.

The study of polyoxometalates formation using capillary zone electrophoresis.

The formation process of polyoxometalates [PMo12 O40 ](3-) and [PMo12 - x Vx O40 ](-3-x) has been studied in aqueous solutions of 0.1 M malonate buffer at pH 2.8-3.

Comparison of sustained low-efficiency dialysis with acetate-free and acetate-containing bicarbonate dialysate in unstable patients.

This work is focused on the problem of maintenance of intradialytic hemodynamic safety in unstable patients with acute kidney injury (AKI). A hypothesis that "small" quantities of acetate in standard bicarbonate dialysate can cause pronounced acetatemia and exacerbate cardiovascular instability was tested. In this prospective randomized study, a group of patients with AKI after cardiac surgery was treated with sustained low-efficiency dialysis with either acetate-containing bicarbonate dialysate or acetate-free dialysate, where acetate is replaced by hydrochloric acid.

Studies on cadmium accumulation by some selected floating macrophytes.

The results of investigation of the process of cadmium accumulation by floating plants of Eichhornia crassipes and Pistia stratiotes are discussed. The main specialty of this study is that it puts more emphasis on the mechanism of penetration of pollutant within the plant and its fate during accumulation act. As a result it was shown that at the first stage of cadmium uptake the sorption of the metal on the surface of the roots due to the presence of carboxylic groups takes place.

Arsenic speciation in natural and contaminated waters using CZE with in situ derivatization by molybdate and direct UV-detection.

A simple and sensitive procedure for simultaneous determination of arsenate, arsenite, monomethylarsonate and dimethylarsinate (DMA) ions in waters using CZE with chemical derivatization in situ and UV-detection at 250 nm was developed. The separation was performed in a fused-silica capillary using solution containing sodium molybdate and sodium perchlorate as electrolyte. Molybdate forms heteropolycomplexes with arsenic species in low acidic media, while sodium perchlorate masks silicate ion.

Mercury speciation in environmental solid samples using thermal release technique with atomic absorption detection.

A sensitive and very simple method for determination of mercury species in solid samples has been developed involving thermal release analysis in combination with atomic absorption (AAS) detection. The method allows determination of mercury(II) chloride, methylmercury and mercury sulfide at the level of 0.70, 0.