[Show abstract][Hide abstract] ABSTRACT: Conjoint liquid chromatography (CLC) on monolithic convective interaction media (CIM) disks coupled on-line to UV and inductively coupled plasma mass spectrometry (ICP-MS) detectors was used for the first time in speciation analysis of Pt in human serum spiked with Pt-based chemotherapeutics. CIM Protein G and CIM DEAE disks were assembled together in a single housing forming a CLC monolithic column. Such a set-up allows rapid two-dimensional separation by affinity and ion-exchange (IE) modes to be carried out in a single chromatographic run. By applying isocratic elution with Tris–HCl–NaHCO3 buffer (pH 7.4) in the first minute, followed by gradient elution with 1 mol L−1 NH4Cl (pH 7.4) in the next 9 min, immunoglobulins (IgG) were retained by the Protein G disk enabling subsequent separation of unbound Pt from Pt bound to transferrin (Tf) and albumin (HSA) on the CIM DEAE disk. Further elution with acetic acid (AcOH) in the next 3 min allowed separation of Pt associated with IgG. Separated Pt species were quantified by post-column isotope dilution—ICP-MS. Pt recovery on the CLC column was close to 100%. In comparison to commonly applied procedures that involve separation of protein peaks by size-exclusion chromatography (SEC) followed by IE separation of metal-based chemotherapeutic fractions bound to serum proteins, the CLC method developed is much faster and simpler. Its sensitivity (LOQs adequate for quantification of all separated Pt species, lower than 2.4 ng Pt mL−1), good selectivity and method repeatability (RSD±3%) enabled investigation of the kinetics of interaction of Pt-based chemotherapeutics with serum proteins and the distribution of Pt species in spiked human serum. Pt species present in spiked serum were bound preferentially to HSA. The proportion of Pt associated with IgG and Tf was lower than 13%. Cisplatin and especially oxaliplatin react rapidly with serum proteins, while carboplatin much less. The method developed may be reliably applied in preclinical and clinical studies of the kinetics of the interaction and distribution of different metallodrugs with proteins in blood serum.
[Show abstract][Hide abstract] ABSTRACT: Recently several papers were published in highly ranked journals on the presence of Cr(VI) in tea infusions, bread samples and plants. These statements were made on the basis of determination of total Cr concentrations in alkaline and aqueous sample extracts by ETAAS, without applying any speciation analysis. If Cr(VI) really exists in bread samples and tea infusions, consumption of bread and tea would represent long-term chronic exposure to Cr(VI) and a health threat for the majority of the human population. It is well accepted that due to the presence of organic matter foodstuffs of plant and animal origin cannot contain Cr(VI). Therefore, to show that the reported data on the presence of Cr(VI) in foodstuffs are an artefact of inappropriately applied analytical methodology, investigation of speciation was carried out by high performance liquid chromatography-inductively coupled plasma mass spectrometry (HPLC-ICP-MS). 50Cr(VI) and 53Cr(III) stable isotopes were used to follow species interconversions during the extraction procedures. Separated Cr species eluted from the column were followed at m/z 50, 52 and 53. The high sensitivity of the HPLC-ICP-MS method (LOD for m/z 52, 0.03 μg Cr(VI) L−1) enabled reliable determination of Cr(VI) at concentration levels that were much lower than the total Cr content present in sample extracts. The speciation analysis data demonstrated that in all samples analysed Cr(VI) concentrations were below the LOD. In tea infusions 50Cr(VI) was almost completely reduced due to the presence of antioxidants, while the high content of organic matter in bread appreciably reduced 50Cr(VI) even in highly alkaline (pH 12) bread extracts. The data confirmed that Cr(VI) does not exist in foodstuffs of plant origin and provided some conclusive evidence that the same can be expected for foods of animal origin.
Journal of Analytical Atomic Spectrometry 02/2013; · 3.40 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: In the present study, total nickel (Ni) concentration was determined in selected food products in Slovenia by inductively coupled plasma mass spectrometry (ICP-MS) after microwave assisted digestion of samples. The accuracy of the analytical procedure was checked by the determination of nickel in SRM 2976 NIST Mussel tissue and SRM 1548a NIST Typical diet standard reference materials. Results confirmed that soya products (yoghurt and tofu), cacao and cacao products (dark and milk chocolates) and hazel nuts are important sources of dietary Ni. The content of Ni in different teas infusions was too low to significantly contribute to Ni daily intake. Cooking of acidic foodstuffs in stainless steel kitchenware leached Ni in concentrations similar to those in teas. Micro-ultrafiltration (MWCO 3000 Da) of cacao cooked in water or milk revealed that Ni in these drinks is present in the form of low molecular mass (LMM) species and that milk proteins are not able to compete for Ni in the presence of LMM-Ni binding ligands.
Journal of Food Composition and Analysis 01/2013; 32(1):83–89. · 2.09 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Aluminum (Al) is mostly produced from bauxite ore, which contains up to 70% of Al(2)O(3) (alumina). Before alumina is refined to aluminum metal, it is purified by hot alkaline extraction. As a waste by-product red mud is formed. Due to its high alkalinity and large quantities, it represents a severe disposal problem. In Kidričevo (Slovenia), red mud was washed with water before disposal, and after drying, covered with soil. In Ajka (Hungary), the red mud slurry was collected directly in a containment structure, which burst caused a major accident in October 2010. In the present work the environmental impact of toxic elements in red mud from Kidričevo and Ajka were evaluated by applying a sequential extraction procedure and speciation analysis. The predominant red mud fraction was the insoluble residue; nevertheless, environmental concern was focused on the highly mobile water-soluble fraction of Al and Cr. Al in the water-soluble Ajka mud fraction was present exclusively in form of toxic [Al(OH)(4)](-), while Cr existed in its toxic hexavalent form. Comparative assessment to red mud from Kidričevo (Slovenia) with a lower alkalinity (pH 9) with that from Ajka demonstrated significantly lower Al solubility and the presence of only trace amounts of Cr(VI), confirming that disposal of neutralized mud is environmentally much more acceptable and carries a smaller risk of ecological accidents. Since during the Ajka accident huge amounts of biologically available Al and moderate Cr(VI) concentrations were released into the terrestrial and aquatic environments, monitoring of Al and Cr(VI) set free during remedial actions at the contaminated site is essential. Particular care should be taken to minimize the risk of release of soluble Al species and Cr(VI) into water supplies and surface waters.
Science of The Total Environment 04/2012; 426:359-65. · 3.26 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The characterisation of a laboratory quality control material (QCM) for dibutyltin (DBT) and tributyltin (TBT) in sewage sludge is described. The reference values were determined by the use of two different types of isotope-dilution mass spectrometry: gas chromatography-mass spectrometry and gas chromatography-inductively coupled plasma mass spectrometry. To avoid possible analytical errors such as non-quantitative extraction and species degradation during sample preparation, different extraction methods were tested (microwave- and ultrasound-assisted extraction and mechanical stirring). The reference values were based on the unweighted means of results from the homogenisation and characterisation studies. The reference values obtained were 1,553 ± 87 and 534 ± 38 ng Sn g(-1) for DBT and TBT, respectively. In the uncertainty budget estimation, the sample inhomogeneity and between-method imprecision were taken into account. The concentrations of DBT and TBT in QCM are similar to those in the harbour sediment certified reference material PACS-2. Likewise, the levels of DBT and TBT are in the range of these compounds normally present in sewage sludge worldwide. In the future, the QCM will be used for an intercomparison study on DBT and TBT in sewage sludge, and as a day-to-day QCM during studies concerning the application of sewage sludge as an additive to artificial soil or as a raw material in civil engineering construction.
Analytical and Bioanalytical Chemistry 03/2012; 403(3):857-65. · 3.66 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Determination of Cr(VI) in aqueous samples including carbonate matrix solutions was performed by fast proteinliquid chromatography (FPLC) coupled to inductively coupled plasma mass spectrometry (ICP-MS). NaCl was used for separation of Cr species representing a high burden of total dissolved solids for plasma. In addition, detection ofCr species in the NaCl and carbonate matrix was severely compromised also by chlorine and carbon polyatomic interferences at m/z 52 and 53. The influence of high amounts of chloride and carbonate ions on detection ofCr species was investigated using ICP-MS with a High Matrix Introduction (HMI) system, which reduced the sample aerosol transport and enabled direct analysis of separated Cr species in the presence of up to 4% NaCl. The potential of Helium Collision mode (He mode) and High Energy Collision Mode (HECM) to reduce polyatomic interferences from chlorine and carbon on m/z 52 and 53 was also evaluated. It was experimentally proven that for efficient removal of chlorine and carbon polyatomic interferences HECM instead of commonly used He mode should be applied. By applying HMI and HECM, determination of Cr(VI) in carbonatebuffer matrices using NaCl as eluent is possible, following the most abundant Cr 52 and 53 isotopes. Despite the use of HMI and HECM, which significantly reduce the analytetransport to plasma and detector, low LODs were obtained for Cr(VI): 0.01 ng mL−1 at m/z 50, 0.06 ng mL−1 at m/z 52 and 0.02 ng mL−1 at m/z 53. The repeatability of the measurement (5 ng Cr(VI) mL−1) was better than ±1.5%. The simple solution of efficient lowering of the blank at low pH arising from a stainless steel injection needle was also demonstrated by the use of the reverse injection of samples.
[Show abstract][Hide abstract] ABSTRACT: In this work, data on the level of organotin compounds (OTCs) in seawater and mussels collected along the entire Croatian Adriatic Coast are presented. The samples were collected in 2009 and 2010 at 48 locations representing different levels of maritime activities, including marinas, ports and reference sites. Butyltins (BuTs) were found in all analyzed samples, representing >97% of OTCs, and ranged from 0.46 to 27.98 ng Sn L(-1) in seawater and from <6 to 1675 ng Sn g(-1) in mussels. The results indicate a recent input of TBT, with the highest concentrations of BuTs found in the marinas. It appears that the Adriatic coast is still polluted with TBT despite the fact that TBT-containing antifouling paints have been banned in Croatia since 2008. It is questionable how much TBT pollution decreased since 2005, when a high incidence of imposex was established in the same area.
[Show abstract][Hide abstract] ABSTRACT: To understand the pathways of Altransport in human body it is necessary to identify and quantify Al species present in human serum. It has been demonstrated that about 90% of Al in human serum corresponds to high molecular mass species (HMM-Al) and that Al is bound exclusively to transferrin (Tf). The remaining Al exists in low molecular mass species (LMM-Al) bound predominantly to Al-citrate. In studies of the efficiencies of the chelation therapies and to perform kinetic studies of Al binding to Tf, rapid and reliable analytical procedures are required. Therefore, a new analytical procedure for the efficient, reliable and fast separation of proteins from LMM compounds in serum was developed by the use of a HiTrap desalting size exclusion column. Unspiked and spiked human serum that was left for six hours to reach approximately thermodynamic equilibrium were studied. The separation of HMM-Al from LMM-Al species was accomplished with tris-HCl buffer (pH 7.4) in 10 min. Al elution profile was followed by ICP-MS detection. In the first 5 min HMM-Al compounds were eluted, followed by the elution of LMM-Al species from 5 to 10 min. Results demonstrated that about 94% of Al was present in the HMM (protein) fraction. To prove the reliability of the fractionation procedure developed, the protein peak and LMM separated species were collected in 5 mL fractions, followed by the previously developed speciation procedures. Speciation of the protein peak by CIM® DEAE-ICP-MS verified that about 98% of Al was bound to Tf. In the LMM serum fraction Al-citrate was separated on the FPLC column coupled to ICP-MS. Speciation data confirmed the reliability of the developed fast fractionation procedure. It represents a promising tool for investigations of kinetics of Al binding to Tf and may also be applied in studies of the efficiencies of the chelation therapies in patients overloaded with Al.
[Show abstract][Hide abstract] ABSTRACT: The energy and nutrient values for military nutrition are defined in the nutritional recommendations of the Slovene Armed Forces. In this study 35 daily military diets sampled in the years 2002 and 2005 by the double basket method were analysed, for energy, total fat, protein, dietary fibre and the elements Ca, Mg, Na, P, K, Fe, Zn, Cu, I and Se. The daily diets were collected at different locations in Slovenia. The aim was to establish whether energy value, content of fat, protein, dietary fibre and selected essential elements are in compliance with the nutritional recommendations of the Slovene Armed Forces. The results indicate that daily intake of essential elements from military meals was sufficient, with the exception of Ca and Zn in diets sampled in 2005. The study was the first in Slovenia analysing daily intakes of essential elements in an adult population aged 19–27 years.
[Show abstract][Hide abstract] ABSTRACT: Monolithic supports are increasingly used in the field of chromatography. They are appropriate for different applications (e.g., separation of biomolecules, organic acids and inorganic anions). However, only a few research groups are investigating the potential of using monolithic phases for rapid separation of metal cations and elemental speciation analysis.Monolithic supports based on porous monolithic silica have been successfully applied in separation of alkaline-earth and transition-metal cations in environmental waters and high ionic-strength samples.The present review covers applications of monolithic supports for chromatographic separation of metal cations and the potential for using monolithic chromatography in elemental speciation analysis. We critically evaluate the performances and the advantages of monolithic supports and compare them to conventional particle-packed chromatographic supports.
[Show abstract][Hide abstract] ABSTRACT: A continuous 60-year record (1938–1998) of stable isotope compositions of carbon and oxygen, as well as trace metal (Mg, Sr, Ba) concentrations in a laminated calcite crust precipitated in a short artificial tunnel on a non-equilibrium groundwater-fed karstic river is presented. Chemical and isotopic records have been compared to hydrometeorological data, available for the last 48 years. An attempt is made to relate isotopic and geochemical variations in the crust to environmental parameters, such as temperature, precipitation and changes in vegetation cover, as well as to postdepositional recrystallisation of the older crust material. Isotopic composition of the crust is largely influenced by non-equilibrium precipitation, which favours the incorporation of isotopically depleted C and O into the carbonate. Furthermore, because of the complicated hydrological situation, there is no observable correlation between the stable oxygen isotope composition of water and temperature. The result is that the 18 O isotopic thermometers overestimate the measured precipitation temperatures. Temperatures calculated from Mg/Ca ratios of water and the carbonate match the δ 18 O palaeotemperatures within ±2.4 °C in the older part of the crust, precipitated before the onset of industrial pollution of the river. It was demonstrated that the application of Mg palaeothermometry in natural systems, where the Mg/Ca ratio of water is influenced not only by temperature, but also by other environmental parameters such as precipitation, surface runoff, groundwater retention time and anthropogenic influences, is subject to a large uncertainty, up to 10 °C.
Chemical Geology 01/2009; 258:242-250. · 3.15 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The extent of pollution with organotin compounds was investigated in water, sediment and bivalve mussels (Mytilus galloprovincialis) from the Northern Adriatic Sea. Butyl-, phenyl- and octyltin species were quantified after extraction and derivatisation
by gas chromatography–mass spectrometry in a total of 99 samples from the period from 2000 to 2006. The accuracies of the
analytical procedures were checked by spiking of unpolluted water samples and by the analysis of standard reference materials
(harbour sediment PACS-2 and mussel tissue ERM-CE 477). Among organotin species analysed in samples butyltins were the predominant.
Tributyltin was found to be present in the highest concentrations, suggesting its recent input into the marine environment.
Butyltins were detected at all sites surveyed (sum of butyltins was up to 718ng Sn L−1, 3,552ng Sn g−1 d.w. and 9,991ng Sn g−1 d.w. in water, sediment and mussel samples, respectively), phenytins in much lower concentrations (up to 31ng Sn L−1, 326ng Sn g−1 d.w. and 442ng Sn g−1 d.w. in water, sediment and mussel samples) and to a much smaller extent, while octyltins were not detected at any location.
The spatial distribution of tributyltin was closely related to boating, with the highest concentrations found in marinas (up
to 586ng Sn L−1 for water samples, 1,995ng Sn g−1 d.w. for sediment and 6,434ng Sn g−1 d.w. for mussel samples). The temporal distribution clearly indicates a decrease of organotin pollution at all sites.
Water Air and Soil Pollution 12/2008; 196(1):211-224. · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Phytoremediation is an emerging technology that employs the use of higher plants for the clean-up of contaminated environments. Progress in the field is however handicapped by limited knowledge of the biological processes involved in plant metal uptake, translocation, tolerance and plant–microbe–soil interactions; therefore a better understanding of the basic biological mechanisms involved in plant/microbe/soil/contaminant interactions would allow further optimization of phytoremediation technologies. In view of the needs of global environmental protection, it is important that in phytoremediation and plant biology studies the analytical procedures for elemental determination in plant tissues and soil should be fast and cheap, with simple sample preparation, and of adequate accuracy and reproducibility. The aim of this study was therefore to present the main characteristics, sample preparation protocols and applications of X-ray fluorescence-based analytical techniques (energy dispersive X-ray fluorescence spectrometry—EDXRF, total reflection X-ray fluorescence spectrometry—TXRF and micro-proton induced X-ray emission—micro-PIXE). Element concentrations in plant leaves from metal polluted and non-polluted sites, as well as standard reference materials, were analyzed by the mentioned techniques, and additionally by instrumental neutron activation analysis (INAA) and atomic absorption spectrometry (AAS). The results were compared and critically evaluated in order to assess the performance and capability of X-ray fluorescence-based techniques in phytoremediation and plant biology studies. It is the EDXRF, which is recommended as suitable to be used in the analyses of a large number of samples, because it is multi-elemental, requires only simple preparation of sample material, and it is analytically comparable to the most frequently used instrumental chemical techniques. The TXRF is compatible to FAAS in sample preparation, but relative to AAS it is fast, sensitive and multi-elemental. The micro-PIXE technique requires rather expensive instrumentation, but offers multi-elemental analysis on the tissue and cellular level.
Spectrochimica Acta Part B Atomic Spectroscopy 01/2008; · 3.14 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The efficiency of different extraction procedures for the simultaneous determination of butyltin compounds in marine sediments by gas chromatography–mass spectrometry (GC--MS) was critically evaluated in the present work. Three different polar solvents (acetic acid, a mixture of acetic acid with methanol, and a mixture of acetic acid, methanol, and water) and three different extraction approaches (mechanical shaking, ultrasonic, and microwave-assisted extraction) were used for the extraction of butyltin compounds from PACS-2 certified marine sediment reference material. Before determination by GC--MS, extracted butyltin species were derivatized with sodium tetraethyl borate and extracted into iso-octane. The results indicated that 30-min ultrasonic extraction with 100% acetic acid provided satisfactory recoveries for all certified butyltins. The developed analytical method was successfully applied for determination of butyltin compounds in coastal sediments of the Northern Adriatic Sea. The results demonstrated that butyltins were present in all sediments analysed.
International Journal of Environmental Analytical Chemistry 08/2007; 87(9):615-625. · 1.24 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Due to the high toxicity of hexavalent Cr, an European directive has recently been issued limiting the content of water-soluble Cr(VI) in cement to a maximal concentration of 2 mg kg−1. In order to fulfil the legislative requirements, it is often necessary to use reducing agents to lower the content of hexavalent Cr in cement. In the present work the abilities of HPLC-ICP-MS, FPLC-ETAAS, spectrophotometry and selective extraction procedure were estimated for the determination of Cr(VI) in aqueous cement extracts, containing high and low Cr(VI) concentrations. After comparison of the analytical performances of the different analytical methods used, water extracts of different cement samples were analysed. A good agreement was obtained for cement samples containing Cr(VI) concentration higher than 6 mg kg−1. Differences between techniques in general did not exceed 10%. With the exception of selective extraction all techniques applied are accurate (recoveries of spiked samples lay between 95–103%) and of adequate sensitivity. The MIBK extraction procedure exhibited limitations in cement samples that were treated with reducing agents due to the gel formation in the organic phase. Because of its accuracy, high sensitivity and the high speed of the analysis, the HPLC-ICP-MS procedure could be recommended as a technique of choice. However, FPLC-ETAAS and spectrophotometry may also be applied for the determination of Cr(VI) in cement samples and cement samples treated with reducing agents.
[Show abstract][Hide abstract] ABSTRACT: The comparison of immobilisation efficiency of various phosphate stabilisation agents for heavy metals in sewage sludge collected from an urban wastewater treatment plant Domale-Kamnik (Slovenia) is reported. The sewage sludge, containing high total concentrations of Zn (2698 8.1 mg kg-1), Ni (1513 5.7 mg kg-1), Cr (1118 3.0 mg kg-1) and Cu (712 2.2 mg kg-1), was mixed with various types of phosphates: highly soluble Ca(H2PO4)2, synthetic hydroxyapatite, with a solubility between Ca(H2PO4)2 and rock apatite, and bone-meal as an alternative low-cost source of poorly crystalline phosphate, in order to reduce metal mobility. The amounts of stabilising agents added to 1 g of the sludge ranged from 0.05 to 1 g. Water and acetic acid extractions were used for the determinationof water-soluble and potentially bioavailable metal fractions in the sewage sludge and its mixtures with various stabilisation agents.
Water Air and Soil Pollution 06/2004; 156(1):57-69. · 1.75 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Al toxicity is well known, particularly in patients with chronic renal failure. To estimate the dietary intake of Al in man it is necessary to determine the total Al concentrations in different foodstuffs. For this purpose twenty one different vegetables growing on peat and clay soils were analysed. Water-soluble Al was determined in soil samples to estimate the easily soluble Al fraction available to plants and to find whether plants may also accumulate higher Al concentrations from soils low in Al. Al was further determined in wheat, eggs, baby foods, fish, mussels and twenty samples of total diet. In addition, beverages and herbal and black tea infusions were analysed for Al content. Total Al in foodstuffs was determined by ICP-AES after microwave digestion. The accuracy of the procedure was checked by the analysis of CRM 1570a (Spinach leaves). Good agreement between measured and certified values was obtained. In order to estimate the extent of leaching from Al utensils, sauerkraut and sour turnip were cooked in Al-cookware. The results indicate that concentrations of Al in foodstuffs (dry weight) were in general below 30 mg kg−1, while in total diet they ranged from 3 to 6 mg kg−1 Al. High Al concentrations were found in mussels (about 300 mg kg−1) parsley and lamb's lettuce. Lamb's lettuce contained about 400 mg kg−1 of Al, irrespective of whether it was growing on peat soil low in total and water-soluble Al or in clay soil rich in Al. Black tea infusions contained up to 300 mg kg−1 of Al, which is 30 times more than herbal tea infusions. Concentrations of Al in beverages were below 0.4 mg dm−3. The results indicated that sauerkraut and sour turnip leach appreciably high concentrations of Al during cooking in Al utensils (313 and 260 mg kg−1, respectively), so the use of such cookware is not recommended for acidic foodstuffs.
[Show abstract][Hide abstract] ABSTRACT: Speciation analysis plays a crucial role in the investigations of transformation and mobility of Cr in the environment. In order to investigate the conditions for safe disposal of chromium-rich waste materials, appropriate speciation techniques regarding specific characteristics of sample matrix should be applied. Partitioning of Cr between various phases in waste materials, in soils, and in waste materials mixed with soils give useful data for the assessment of the environmental hazards. For this purpose, it is necessary to apply long-term experiments and to study possible oxidation-reduction processes of Cr after disposal of waste to various soils. On the basis of complex investigations estimation can be done on conditions for safe disposal of chromium-rich waste materials.