Structures, Antioxidant Properties, and Antimicrobial Properties of Eu(III), Gd(III), and Dy(III) Caffeinates and p-Coumarates.

In this study, we investigated the structures of lanthanide (Eu(III), Dy(III), and Gd(III)) complexes with p-coumaric (p-CAH2) and caffeic (CFAH3) acids using the FTIRKBr, FTIRATR, and Raman spectroscopic methods. The compositions of the solid phase caffeinates and p-coumarates were obtained on the basis of the amounts of hydrogen and carbon determined using an elemental analysis. The degree of hydration and the thermal decomposition of each compound were examined via a thermal analysis of TG, DTG, and DSC. Antioxidant spectroscopic tests were performed using the DPPH (1,1-diphenyl-2-picrylhydrazyl radical), FRAP (ferric reducing antioxidant activity), and ABTS (2,2'-azino-bis-(3-ethylbenzothiazoline-6-sulfonic acid) (diammonium salt radical cation) methods. The antimicrobial activity of each compound against Escherichia coli, Bacillus subtilis, and Candida albicans was investigated. The electrical properties of the liposomes which mimicked the microbial surfaces formed in the electrolyte containing the tested compounds were also investigated. The above biological properties of the obtained complexes were compared with the activities of p-CAH2 and CFAH3. The obtained data suggest that lanthanide complexes are much more thermally stable and have higher antimicrobial and antioxidant properties than the ligands (with the exception of CFAH3 in the case of antioxidant activity tests). The Gd(III) complexes revealed the highest biological activity among the studied lanthanide complexes.

Caffeic Acid/Eu(III) Complexes: Solution Equilibrium Studies, Structure Characterization and Biological Activity.

Caffeic acid (CFA) is one of the various natural antioxidants and chemoprotective agents occurring in the human diet. In addition, its metal complexes play fundamental roles in biological systems. Nevertheless, research on the properties of CFA with lanthanide metals is very scarce, and little to no chemical or biological information is known about these particular systems. Most of their properties, including their biological activity and environmental impact, strictly depend on their structure, stability, and solution behaviour. In this work, a multi-analytical-technique approach was used to study these relationships for the Eu(III)/CFA complex. The synthesized metal complex was studied by FT-IR, FT-Raman, elemental, and thermal (TGA) analysis. In order to examine the chemical speciation of the Eu(III)/CFA system in an aqueous solution, several independent potentiometric and spectrophotometric UV-Vis titrations were performed at different M:L (metal:ligand) and pH ratios. The general molecular formula of the synthesized metal complex in the solid state was [Eu(CFA)3(H2O)3]∙2H2O (M:L ratio 1:3), while in aqueous solution the 1:1 species were observed at the optimum pH of 6 ≤ pH ≤ 10, ([Eu(CFA)] and [Eu(CFA)(OH)]-). These results were confirmed by 1H-NMR experiments and electrospray-ionization mass spectrometry (ESI-MS). To evaluate the interaction of Eu(III)/CFA and CFA alone with cell membranes, electrophoretic mobility assays were used. Various antioxidant tests have shown that Eu(III)/CFA exhibits lower antioxidant activity than the free CFA ligand. In addition, the antimicrobial properties of Eu(III)/CFA and CFA against Escherichia coli, Bacillus subtilis and Candida albicans were investigated by evaluation of the minimum inhibitory concentration (MIC). Eu(III)/CFA shows higher antibacterial activity against bacteria compared to CFA, which can be explained by the highly probable increased lipophilicity of the Eu(III) complex.

The Mineral Profile of Polish Beers by Fast Sequential Multielement HR CS FAAS Analysis and Its Correlation with Total Phenolic Content and Antioxidant Activity by Chemometric Methods.

Beer is the most common alcoholic beverage worldwide, and is an excellent source of macro- and microelements, as well as phenolic compounds. In this study, a fast method for the determination of Na, K, Mg, Ca, Fe, Mn, and Cu in beer was developed using flame atomic absorption spectrometry. The precision of this method was between 0.8 and 8.0% (as the relative standard deviation (RSD)), and limits of detections were in the range of 0.45 (Mn)-94 µg/L (Na). Among the macroelements tested in the beer samples, K was found at the highest concentration, whereas Na was found at the lowest concentration level. Beer also turned out to be a good source of Mg and K. The total phenolic content (TPC) was determined by the Folin-Ciocalteu method, while the antioxidant activity was estimated by the ABTS method. The results show remarkable variations in the mineral content, TPC, and antioxidant activity across the beer types and brands. Moreover, the relations between the type, color, refraction index, antioxidant activity, extract, alcohol, mineral, and the total phenolic contents were investigated using the factor analysis of mixed data (FAMD) combined with hierarchical clustering on principal components (HCPC).

Speciation of Chromium in Alkaline Soil Extracts by an Ion-Pair Reversed Phase HPLC-ICP MS Method.

The aim of this work was to study by a hyphenated HPLC-ICP MS technique the chromium species released during alkaline extraction of various soils collected from a contaminated area of an old tannery. An ultrasound-assisted extraction procedure using 0.1 mol L-1 Na2CO3 solution was developed for the release of chromium species from the soil. The chromium species in the soil extracts were separated on a C8 column using EDTA and TBAH solution as a mobile phase. The use of an ICP-QQQ MS spectrometer in tandem mass configuration (MS/MS) combined with an octopole reaction system (ORS³) pressurized with helium allows one to eliminate spectral interferences during Cr determination in the soil extracts. The detection limit of the procedure was 0.08 µg L-1 for Cr(III) and 0.09 µg L-1 for Cr(VI) species. The trueness of the IP RP HPLC-ICP MS method was proved by an analysis of CRM 041 and CRM 060. The advantage of the proposed method is the analysis of soil extracts without their preliminary neutralization, which limits the losses of Cr(VI) due to the reduction process. The analysed soils mainly contained chromium in immobile forms (94.6⁻98.5% of the total Cr content). In all alkaline soil extracts mostly the Cr(VI) form was found, but in the extract of organic soils Cr(III) was also present. This arose from the reduction of Cr(VI) species by organic matter (humic acids) and Fe(II). The amount of formed Cr(III) species was dependent on the type of soil (content of organic matter, Mn and Fe) and its moistness. For the first time, the presence of neutral and non-polar chromium fractions in the soil extracts was also demonstrated. It was found that reliable speciation analysis results could be obtained for mineral soils.

Fast and simple procedure for fractionation of zinc in soil using an ultrasound probe and FAAS detection. Validation of the analytical method and evaluation of the uncertainty budget.

A new fast method for determination of mobile zinc fractions in soil is proposed in this work. The three-stage modified BCR procedure used for fractionation of zinc in soil was accelerated by using ultrasounds. The working parameters of an ultrasound probe, a power and a time of sonication, were optimized in order to acquire the content of analyte in soil extracts obtained by ultrasound-assisted sequential extraction (USE) consistent with that obtained by conventional modified Community Bureau of Reference (BCR) procedure. The content of zinc in extracts was determined by flame atomic absorption spectrometry. The developed USE procedure allowed for shortening the total extraction time from 48 h to 27 min in comparison to conventional modified BCR procedure. The method was fully validated, and the uncertainty budget was evaluated. The trueness and reproducibility of the developed method was confirmed by analysis of certified reference material of lake sediment BCR-701. The applicability of the procedure for fast, low costs and reliable determination of mobile zinc fraction in soil, which may be useful for assessing of anthropogenic impacts on natural resources and environmental monitoring purposes, was proved by analysis of different types of soil collected from Podlaskie Province (Poland).

Ultrasound assisted extraction for determination of mobile fractions of copper in soil.

BACKGROUND: For evaluation of the mobility of metals present in soil various approaches based on sequential extraction procedures (Tessier's, BCR or modified BCR) have been proposed, but they are very laborious and time-consuming. OBJECTIVE: The aim of this study was to develop a new fast extraction procedure for the determination of mobile fractions of copper in soil. MATERIAL AND METHODS: The samples of soil that vary in terms of physicochemical properties and certified reference material (BCR-701) were used in this study. The three-stage modified BCR procedure used for fractionation of copper in soil was accelerated by ultrasound irradiation using an ultrasonic probe. The content of copper in soil extracts was determined by electrothermal atomic absorption spectrometry (ETAAS). RESULTS: The extraction conditions for separation of mobile fractions of copper from soil with the use of ultrasonic probe were optimized. The working parameters of the probe were as follows: the power was 15 W for all fractions while the sonication time was 7 min, 10 min and 6 min for fraction I, fraction II and fraction III, respectively. The developed procedure was validated; linearity of calibration graphs, limit of detection and limit of quantification, accuracy and repeatability of the procedure were evaluated. The content of copper in fraction I-III in soil samples collected from Podlaskie Voivodeship was at the level of 0.09-1.92 mg x kg(-1), whereas its pseudo-total content was in the range 2.75-9.75 mg x kg(-1). CONCLUSIONS; The developed ultrasound assisted sequential extraction procedure allowed for shortening the total extraction time from 48 h to 27 minutes in comparison to conventional modified BCR procedure. The studied soil contains a low pool of copper bioavailable to plants because a sum of mobile fractions (FI-FIII) represents only 22-46% of its pseudo-total content.

Photosynthesis governed by nanoparticulate titanium dioxide. The Pisum sativum L. case study.

Wide availability of anthropogenic TiO2 nanoparticles facilitates their penetration into environment and prompts interactions with plants. They alter plants growth and change their nutritional status. In particular, metabolic processes are affected. In this work the effect of nanometric TiO2 on photosynthesis efficiency in green pea (Pisum sativum L.) was studied. Hydroponic cultivations with three Ti levels (10; 50 and 100 mg L-1) were applied. At all concentrations nanoparticles penetrated into plant tissues and were detected by the single particle ICP-MS/MS method. Nanoparticles altered the CO2 assimilation rate and gas exchange parameters (i.e. transpiration, stomatal conductance, sub-stomatal CO2 concentration). The most pronounced effects were observed for Ti 50 mg L-1 cultivation where photosynthesis efficiency, transpiration and stomatal conductance were increased by 14.69%, 4.58% and 8.92%, respectively. They were further confirmed by high maximum ribulose 1,5-bisphosphate carboxylation rate (27.40% increase), maximum electron transport rate (21.51% increase) and the lowest CO2 compensation point (45.19% decrease). Furthermore, concentrations of Cu, Mn, Zn, Fe, Mg, Ca, K and P were examined with the most pronounced changes observed for elements directly involved in photosynthesis (Cu, Zn, Mn, and Fe). The Cu concentrations in roots, stems and leaves for Ti 50 mg L-1 cultivation were below the control by 33.15%, 38.28% and 10.76%, respectively. The Zn content in analogous treatment and organs decreased by 30.24%, 26.69% and 13.35%. The Mn and Fe levels in leaves were increased by 72.22% and 50.32%, respectively. Our results indicated that plant defence mechanisms which restrain the water uptake have been overcome in pea by photocatalytic activity of nanoparticulate TiO2 which stimulated photosynthesis. On the contrary to the substantial stomatal conductance, the transpiration has been reduced because exceptional part of water flow was already consumed in chloroplasts and could not have been freed to the atmosphere.

Ga complexes of 8-hydroxyquinoline-2-carboxylic acid: Chemical speciation and biological activity.

The binding ability of 8-hydroxyquinoline-2-carboxylic acid (8-HQA) towards Ga3+ has been investigated by ISEH+ (Ion Selective Electrode, glass electrode) potentiometric and UV/Vis spectrophotometric titrations in KCl(aq) at I = 0.2 mol dm-3 and at T = 298.15 K. Further experiments were also performed adopting both the metal (with Fe3+ as competing cation) and ligand-competition approaches (with EDTA as competing ligand). Results gave evidence of the formation of the [Ga(8-HQA)]+, [Ga(8-HQA)(OH)], [Ga(8-HQA)(OH)2]- and [Ga(8-HQA)2]- species, the latter being so far the most stable, as also confirmed by ESI-MS analysis. Experiments were also designed to determine the stability constants of the [Ga(EDTA)]- and [Ga(EDTA)(OH)]2- in the above conditions. Due to the relevance of Ga3+ hydrolysis in aqueous systems, literature data on this topic were collected and critically analyzed, providing equations for the calculation of mononuclear Ga3+ hydrolysis constants at T = 298.15 K, in different ionic media, in the ionic strength range 0 < I / mol dm-3 ≤ 1.0. The synthesis and characterization (by ElectroSpray Ionization - Mass Spectrometry (ESI-MS), Attenuated Total Reflectance - Fourier-Transform Infrared Spectroscopy (ATR-FTIR) and ThermoGravimetric Analysis (TGA)) of Ga3+/8-HQA complexes were also performed, identifying [Ga(8-HQA)2]- as the main isolated species, even in the solid state. Finally, the potential effects of 8-HQA and Ga3+/8-HQA complex towards human microbiota exposed to ionizing radiation were evaluated (namely Actinomyces viscosus, Streptococcus mutans, Streptococcus sobrinus, Pseudomonas putida, Pseudomonas fluorescens and Escherichia coli), as well as their anti-proliferative and anti-inflammatory properties. A radioprotective effect of Ga3+/8-HQA complex was observed on Actinomyces viscosus, while showing a potential radiosensitizing effect against Streptococcus mutans and Streptococcus sobrinus. No cytotoxicity on RAW264.7 murine macrophage cells was observed, neither for the free ligand or Ga3+/8-HQA complex. Nevertheless, Ga3+/8-HQA complex highlighted potential anti-inflammatory properties.

Chemometric approach to discrimination and determination of binary mixtures of silver ions and nanoparticles in consumer products by graphite furnace atomic absorption spectrometry.

Extensive use of nanomaterials in consumer products inevitably leads to their release to the environment. For monitoring of the fate of nanoparticles in various matrices, low-cost, simple and rapid size-based methods are required. Graphite furnace atomic absorption spectrometry (GFAAS) can be used for this purpose, because due to the difference between a thermal energy required to atomize ionic silver (Ag+) and silver nanoparticles (AgNPs) of different size, the maxima of signals measured by are slightly shifted in time. However, signals are seriously overlapped. Analytical signals of various concentrations of Ag+ and differently sized AgNPs in their mixtures were registered under optimized temperature conditions using GFAAS. The research aim was to develop a procedure for quantitative and qualitative analyses of Ag species in the binary mixtures without the need for the deconvolution of their signals into single components. For evaluation of the qualitative composition of the silver forms present in the studied samples, soft independent modeling of class analogy (SIMCA) was applied. The best results were obtained based on the first derivative of absorption signal. The correct identification rate of the Ag forms was only in the range 25-60% depending on the composition of the tested samples, that indicates limitations of this approach. For estimating the concentrations of the Ag forms, partial least squares regression (PLSR) was implemented. The errors levels (expressed as the root mean squared error of prediction of concentration) for mixtures were acceptable and comparable between the studied databases. The developed model was applied for determination of silver species in personal care products. The errors oscillating up to 7.5% for the sum of Ag species are within the limits of the relative prediction error determined from the research studies while building the model.

Changes in growth, biochemical components, and antioxidant activity in aquatic plant Wolffia arrhiza (Lemnaceae) exposed to cadmium and lead.

The present study investigated the biochemical response of aquatic plant Wolffia arrhiza (Lemnaceae) treated with lead (Pb) and cadmium (Cd) at a range of concentrations from 1 to 1000 microM. W. arrhiza has been identified as good scavenger of heavy metals from aqueous solution. Pb and Cd accumulation was found to be increased in a concentration- and duration-dependent manner. However, the highest biosorption of heavy metals was found in plants exposed to low levels (10 microM) of Cd and Pb in the nutrient medium. In observing the response to heavy-metal stress, we noted inhibited plant growth and decreased photosynthetic pigments, monosaccharides, and proteins. In addition, Cd was found to be more toxic to plants than Pb. Heavy metals also induced oxidative damage as evidenced by increased lipid peroxidation and hydrogen peroxide levels. In contrast, the deleterious effects resulting from the cellular oxidative state can be alleviated by enzymatic (catalase, ascorbate peroxidase, nicotinamide dinucleotide [NADH] peroxidase) and nonenzymatic (ascorbate, glutathione) antioxidant mechanisms activated in W. arrhiza plants exposed to Cd and Pb, especially at 10 microM. These results suggest that W. arrhiza is a promising bioindicator of heavy-metal toxicity.

Puparial Cases as Toxicological Indicators: Bioaccumulation of Cadmium and Thallium in the Forensically Important Blowfly Lucilia sericata.

In this study, we present entomotoxicological data on the accumulation of cadmium and thallium in a forensically important blowfly, Lucilia sericata, and evaluate the reliability and utility of such information as toxicological evidence for poisoning as a cause of death. We observed that Cd and Tl content in different growing stages of L. sericata (larvae, puparial cases, and adults) was increasing with increasing metal concentration in the feeding substrate, namely metal-enriched liver. However, patterns of accumulation differed between the two metals investigated, showing a linear relationship for Cd and a saturable pattern for Tl. For cadmium, the highest bioaccumulation factor (BAF) was found in the larval stage (in the range of 0.20-0.25), while for thallium, puparial cases accumulated more metal than the other stages tested (BAF in the range of 0.24-0.42). Thallium was also observed to have a negative effect on larval growth, resulting in lower weight and smaller puparial size. With this study, we update the information on the bioaccumulation of cadmium in forensically important blowflies and provide the first report on the bioaccumulation of thallium as well as its developmental impact in blowflies. Specifically, our results suggest that analysis of puparial cases could yield useful information for entomotoxicological investigations. The content of Cd and Tl in larvae, puparial cases, and adults of L. sericata was determined by inductively coupled plasma mass spectrometry (ICP-MS). The validation parameters of the method such as sensitivity, detection limits, quantification limits, precision, and accuracy were evaluated. The method detection limit (MDL) for all types of samples was in the range of 1.6-3.4 ng g-1 for Cd and 0.034-0.15 ng g-1 for Tl, and the accuracy of the method was confirmed by a high recovery of metals from certified reference materials (91.3% for Cd and 94.3% for Tl).

Method development for determination of trace amounts of palladium in environmental water samples by ICP-MS/MS after pre-concentration on thiol-functionalized MCM-41 materials.

The anthropogenic cycle of Pd in the environment, its fate and impact is still unknown due to limitations of measurement techniques. For separation and pre-concentration of Pd(II) ions, mesoporous silica materials MCM-41 were synthesized and functionalized with different amounts of 3-mercaptopropyltrimethoxysilane (MPTMS) by co-condensation and grafting methods. The structural and textural properties of materials were characterized using XRD, TEM, SEM and BET techniques. The results proved that functionalization with thiol groups did not significantly affect structural and textural parameters of synthesized sorbents. The Pd(II) ions were quantitatively retained on sorbents functionalized by grafting in acidic solutions (pH 2), efficiently eluted with 0.1 mol L-1 thiourea solution in 1 mol L-1 HCl and determined by electrothermal atomic absorption spectrometry (ETAAS). The limit of detection (LOD) of the developed SPE ETAAS method was 0.06 ng mL-1, and the pre-concentration factor was 30. For analysis of Pd in environmental water samples inductively coupled plasma mass spectrometry (ICP-MS) in MS/MS mode was used. Spectral interferences on 105Pd caused by the presence of Sr in water samples were eliminated using helium (5 mL min-1) or ammonia (7 mL min-1) gas in collision/reaction cell. The developed SPE ICP-MS method is characterized by good selectivity in the presence of interfering elements and chloride ions and detection limit of 0.0002 ng mL-1. Its accuracy was confirmed by analysis of spiked water samples. The application of ICP-MS together with efficient separation/pre-concentration of analyte on thiol-functionalized MCM-41 sorbents allows to determine Pd in environmental water samples at pg mL-1 level.

Biologically Active Compounds of Plants: Structure-Related Antioxidant, Microbiological and Cytotoxic Activity of Selected Carboxylic Acids.

Natural carboxylic acids are plant-derived compounds that are known to possess biological activity. The aim of this review was to compare the effect of structural differences of the selected carboxylic acids (benzoic acid (BA), cinnamic acid (CinA), p-coumaric acid (p-CA), caffeic acid (CFA), rosmarinic acid (RA), and chicoric acid (ChA)) on the antioxidant, antimicrobial, and cytotoxic activity. The studied compounds were arranged in a logic sequence of increasing number of hydroxyl groups and conjugated bonds in order to investigate the correlations between the structure and bioactivity. A review of the literature revealed that RA exhibited the highest antioxidant activity and this property decreased in the following order: RA > CFA ~ ChA > p-CA > CinA > BA. In the case of antimicrobial properties, structure-activity relationships were not easy to observe as they depended on the microbial strain and the experimental conditions. The highest antimicrobial activity was found for CFA and CinA, while the lowest for RA. Taking into account anti-cancer properties of studied NCA, it seems that the presence of hydroxyl groups had an influence on intermolecular interactions and the cytotoxic potential of the molecules, whereas the carboxyl group participated in the chelation of endogenous transition metal ions.

Selective Separation of Chromium Species from Soils by Single-Step Extraction Methods: a Critical Appraisal.

A critical appraisal of single-step extraction procedures of chromium species from soil was done in terms of their selectivity towards Cr(III) and Cr(VI) species. Samples of natural mineral and organic soil and samples of soil enriched with different chromium compounds of various solubility (in liquid or solid form) were used to simulate contamination of soil by liquid and solid wastes. The efficiency of extraction of Cr(III) and Cr(VI) species with various reagents, e.g. acetic acid, chelating agents (EDTA, DTPA) or inorganic salts (phosphates and carbonates), was evaluated on the basis of recovery results obtained for enriched samples. None of used reagents allow for quantitative extraction of added Cr(III) form. Procedures based on extraction of soil with Na2CO3 at room and elevated temperature (90-95 °C) were suitable for extraction of Cr(VI) species from mineral soil, whereas for organic soil, the procedure based on extraction with Na2CO3 at room temperature was recommended. The developed extraction procedures were validated using certified reference material (CRM 041 soil) and applied for analysis of contaminated soil samples. The studies showed that the physical state of waste, initial form and oxidation state of chromium and soil properties influenced the final chromium species and their mobility in soil, which have an impact on contamination of environment. The analysis of contaminated soil samples from a tannery area showed that the share of Cr(VI) was very low (only 0.8-4.5%) despite the high total content of chromium, which confirmed that chromium was present in immobile forms.

Recent Advances in On-Line Methods Based on Extraction for Speciation Analysis of Chromium in Environmental Matrices.

The biological activity of Cr(III) and Cr(VI) species, their chemical behavior, and toxic effects are dissimilar. The speciation analysis of Cr(III) and Cr(VI) in environmental matrices is then of great importance and much research has been devoted to this area. This review presents recent developments in on-line speciation analysis of chromium in such samples. Flow systems have proved to be excellent tools for automation of sample pretreatment, separation/preconcentration of chromium species, and their detection by various instrumental techniques. Analytical strategies used in chromium speciation analysis discussed in this review are divided into categories based on selective extraction/separation of chromium species on solid sorbents and liquid-liquid extraction of chromium species. The most popular strategy is that based on solid-phase extraction. Therefore, this review shows the potential of novel materials designed and used for selective binding of chromium species. The progress in miniaturization of measurement systems is also presented.

Chromium Speciation in Wastewater and Sewage by Solid-Phase Extraction Using a New Diphenylcarbazone-Incorporated Resin.

A new procedure for the determination of chromium species in polluted environmental samples by flame atomic absorption spectrometry was developed in this work. A new material containing 1,5-diphenylcarbazone included in a polymeric matrix was prepared and employed as a solid-phase extraction material for selective separation of Cr(III) ions under dynamic conditions. Chromium(III) ions were retained on this sorbent with high efficiency and repeatability (95 %, RSD = 1 %) from solutions with pH 9.0. The quantitative recovery of analyte was obtained with 0.1 mol L-1 EDTA. The concentration of Cr(VI) ions was calculated from the difference between the concentration of total chromium and Cr(III) ions. The prepared sorbent exhibits good chemical and mechanical stability, sorption capacity and selectivity towards Cr(III) ions in the presence of Cu(II), Ni(II), Mn(II) and Ca(II) ions. The accuracy of the separation method was proved by analysis of reference material of wastewater RES 10.2. The developed procedure was applied for chromium speciation analysis in municipal sewage samples.

An ultrasound-assisted procedure for fast screening of mobile fractions of Cd, Pb and Ni in soil. Insight into method optimization and validation.

A fast ultrasound-assisted sequential extraction (UASE) procedure for the determination of cadmium, lead and nickel fractions in soil was developed and fully validated. The working parameters of an ultrasound probe were optimized by comparing the content of metals in soil extracts obtained by the UASE procedure with that obtained by the conventional (with the aid of a vertical rotor) modified Community Bureau of Reference (BCR) procedure. The content of metals in soil fractions was determined by electrothermal atomic absorption spectrometry. The total time of extraction of metals from soil was shorten from 48 h to 27 min (total sonication time). The trueness of the developed method was confirmed by analysis of the certified reference material BCR-701. In order to indicate critical points of the developed UASE method, uncertainties of fractionation results were calculated and compared with those calculated for conventional modified BCR procedure. The method usefulness was tested for the determination of metal fractions in different types of soil collected in the Podlasie Province (Poland). The proposed procedure could be used for fast screening of mobile fractions of several heavy metals in soil.

Protective role of 20-hydroxyecdysone against lead stress in Chlorella vulgaris cultures.

Treatment of cultured C. vulgaris cells with 10(-6)-10(-4) M lead decreased their growth and chemical composition during the first 48 h of cultivation. However, at concentrations above 10(-4) M, lead is cytotoxic to Chlorella vulgaris cells, resulting in cellular fragmentation and lysis. In contrast, at concentrations below 10(-6) M lead had no influence on the growth and metabolism of C. vulgaris cells. 20-Hydroxyecdysone (20E) (10(-10)-10(-8) M) increased growth and chemical composition of C. vulgaris cells over a concentration range. Levels per cell of chlorophylls, protein, sugars are all increased by 20E treatment, when compared to non-treated control cells. However, the cultures treated with 20E and lead show a lower stimulation than the cultures treated with 20E alone. The effects of 20E mixed with lead on the growth and the level of cellular lead, chlorophyll, sugar and protein in C. vulgaris are also reported. The decreased growth and composition of C. vulgaris cells treated with lead was restored by the 20E. Application of 20E to C. vulgaris cultures reduced the impact of lead stress on growth, prevented chlorophyll, sugar and protein loss and increased phytochelatins synthesis. Furthermore, 20E did not restore toxic effect of lead on C. vulgaris cells. The combined treatment with lead and 20E appeared to have a stimulatory effect on the above parameters during the 48 h of cultivation, as compared to the control. 20E reduced the toxicity of lead and the growth recovered to the level of cells treated with 20E alone. Concentration-dependent stimulation was observed with increasing concentration of 20E and decreasing concentration of lead.

Platinum, palladium and rhodium content in road dust, tunnel dust and common grass in Bialystok area (Poland): a pilot study.

Automobile traffic is the main source of Pt, Pd and Rh, i.e. platinum-group elements (PGEs), contamination in urban areas and there is growing concern about the effects of these emerging contaminants for people living in these areas. PGE contents were determined in samples of road dust, tunnel dust and common grass as well as pine needles collected from the residential areas of Bialystok, northeast Poland. High resolution (HR) and quadrupole inductively coupled plasma mass spectrometry (ICP-MS) were compared for their adequacy in the environmental analysis of Pt and Rh. Palladium was determined by total X-ray fluorescence (TXRF) and HR-ICP-MS after matrix separation by reductive co-precipitation with Hg. The highest PGEs concentration was found in road dust samples. Platinum content in road dust varied from 34.2 to 110.9 ng g(-1), while that of Rh from 6.0 to 19.7 ng g(-1). The mean concentration of Pd in this matrix was 32.8 ng g(-1) as determined by TXRF analysis and 42.2 ng g(-1) by HR-ICP-MS. The highest Pt concentration in tunnel dust was found in the size fraction below 75 microm (22.3-23.3 ng g(-1)). The mean concentrations of PGEs in grass were 8.63 ng g(-1) for Pt, 0.65 ng g(-1) for Rh and 3.2 ng g(-1) for Pd. The concentration of PGEs in pine needles was below the limits of detection of the methods used.

A new ion imprinted polymer based on Ru(III)-thiobarbituric acid complex for solid phase extraction of ruthenium(III) prior to its determination by ETAAS.

A new ruthenium ion imprinted polymer was prepared from the Ru(III) 2-thiobarbituric acid complex (the template), methacrylic acid or acrylamide (the functional monomers), and ethylene glycol dimethacrylate (the cross-linking agent) using 2,2'-azobisisobutyronitrile as the radical initiator. The ion imprinted polymer was characterized and used as a selective sorbent for the solid phase extraction of Ru(III) ions. The effects of type of functional monomer, sample volume, solution pH and flow rate on the extraction efficiency were studied in the dynamic mode. Ru(III) ion was quantitatively retained on the sorbents in the pH range from 3.5 to 10, and can be eluted with 4 mol L-1 aqueous ammonia. The affinity of Ru(III) for the ion imprinted polymer based on the acrylamide monomer is weaker than that for the polymer based on the methacrylic acid monomer, which therefore was used in interference studies and in analytical applications. Following extraction of Ru(III) ions with the imprint and their subsequent elution from the polymer with aqueous ammonia, Ru(III) was detected by electrothermal atomic absorption spectrometry with a detection limit of 0.21 ng mL-1. The method was successfully applied to the determination of trace amounts of Ru(III) in water, waste, road dust and platinum ore (CRM SARM 76) with a reproducibility (expressed as RSD) below 6.4 %. FigureThe new ion imprinted polymer was prepared and used for the separation of ruthenium from water and most complex environmental samples, such as road dust and platinum ore (CRM SARM 76) prior ETAAS determination.