Low Molecular Mass Species Research Articles

Effects of deep eutectic solvents pretreatment on coal physicochemical characteristics

ABSTRACT Coal is a major resource in China both for chemicals production and power generation, but its impact on the environment demands attention. Solvent pretreatment is an effective method to realize cleaner utilization of coal. Shendong sub-bituminous coal was treated with three different deep eutectic solvents (DESs) – choline chloride (ChCl)-urea, ChCl-glycerol, and ChCl- ethylene glycol – at temperature as low as 120°C. Proximate/ultimate analyses, scanning electron microscopy, thermogravimetric analysis, and Fourier transform infrared spectroscopy were used to examine the physicochemical changes that occurred in coal after DESs treatment. Results showed that DES treatment led to coal fragmentation and decreased average particle size. Compared with raw coal (33.1%), DES-treated coal showed greater mass loss (35.2 − 37.7%), showing that the amount of low molecular mass species increased after treatment. This was confirmed by the observation that DES-treated coal had more volatile components and less minerals and functional groups that contained oxygen (especially C−O). The content of elemental sulfur also decreased from 0.26% to 0.10 − 0.15% after DES treatment, along with a reduction in aliphatic chain length and aromatic substitution degree, which were from 10.73 to 9.33−10.08 and 16.70% to 10.73−15.36%, respectively. The macromolecular structure of the coal was destroyed as a result of DES’s interactions with the weak covalent bonds and hydrogen bonds in the coal. These results suggest that DES has the potential to be used as a pretreatment solvent for coal conversion.

Reactive Molecular Dynamics Simulation of Kerogen Thermal Maturation and Cross-Linking Pathways

Molecular dynamics simulations were performed with a ReaxFF reactive force field to investigate bond breaking and bond formation mechanisms during the thermal maturation of three kerogens and potential cross-linking pathways toward the formation of three-dimensional (3D) quasi-infinite molecular networks (cross-linked kerogen macromolecules). Starting with small ensembles of high molecular mass models for immature type I Green River Shale kerogen (kerogen 1-I), top of the oil window type II kerogen (kerogen 2-L), and low maturity type III kerogen (kerogen 3-L), low molecular mass species including H2O, C2H4, and C3H6 were produced as the maturities of the remaining kerogens increased. Highly reactive fragments, which are not detected in pyrolysis experiments, were also produced. Further, the cross-linking mechanisms in the newly developed polymeric kerogen networks appear to be highly complex, and covalent —C–S—, —C–O—, and —C–C— bonds were the primary cross-links that structurally bond kerogen monomers t...

Human Serum Low Molecular Mass Prostate-specific Antigen As Biomarker.

SummaryBackgroundProstate-specific antigen (PSA) is a glycoprotein tumor marker known to exist as numerous glycospecies. Investigations on its glycobiochemical properties aimed at their use in the preparation of adjuncts in determining PSA concentration for clinical purposes have accumulated a lot of data on its structural properties. In this study, we reconsidered unexplored ubiquitously present low molecular mass species of PSA regarding to molecular mass, origin and pathophysiological source specificity in order to evaluate them as biomarkers.MethodsData on low molecular mass PSA-immunoreactive species from sera of subjects with prostate cancer (PCa), benign prostatic hyperplasia (BPH), breast cancer (BCa), and urine of healthy males obtained by on-chip immunoaffinity chromatography combined with mass spectrometry were analyzed.ResultsThe results obtained indicated PSA species common to BCa, PCa, and BPH at 12-13 kDa, 17-19 kDa and 21-24 kDa. The striking difference in predominant frequencies made the profile characteristic in each examined pathophysiological condition. On the other hand, paired groups of prostatic and extraprostatic PSA contained rare species with small differences among groups concerning individual species. Low molecular mass PSA also included rare species unique for each group of samples.ConclusionThe results obtained revealed that uniformity of low molecular mass PSA-immunoreactive species in sera prevails over diversity related to cancer and non-cancer conditions, but at the same time some of them are molecules with biomarker potential for BPH detection.

204 - Characterising the Reactions of Diselenides with Reactive Oxidants Generated During Chronic Inflammation

Introduction Activated leukocytes present at sites of injury or infection releases enzymes that produce reactive oxidants including hydrogen peroxide (H2O2), hypochlorous acid (HOCl), singlet oxygen (1O2), various peroxides and free radicals. These oxidants play a key role in killing pathogens but excessive or inappropriate formation can give rise to host tissue damage and oxidative stress, and this been associated with multiple human pathologies. Recent kinetic data have shown selenium-containing compounds (selenols RSeH, and selenides RSeR) react rapidly with multiple oxidants and are readily recycled (by GSH and enzymes) to their reduced form, allowing catalytic activity. Hypothesis Readily available diselenides (RSeSeR) may act as highly efficient oxidant scavengers of biologically-relevant oxidants. Results The diselenides selenocystamine (SeCA), diselenodipropionic acid (DSePA) and glutathione diselenide (GSeSeG) react rapidly with HOCl, H2O2 and a range of organic hydroperoxides as assessed via UV/vis spectroscopy. These reactions are more rapid with HOCl than with H2O2, with the second order rate constants for reaction with H2O2 being in the range 10-2(for DSePA) to ~10-4 M-1 s-1 (SeCA and GSeSeG). The oxidation products of the fluorescently-labeled diselenide, Fmoc-selenocystine, have been characterised using UPLC and LC-MS/MS. Oxidation by HOCl and H2O2 results in cleavage of the diselenide bond (with a loss of absorption at 300 nm) and formation of low molecular mass species in a dose- and time-dependent manner. The seleninic acid (RSeO2H) is a major oxidation product. Conclusions Readily available and stable diselenides are rapidly oxidised by biologically-relevant oxidants, and may act as efficient oxidant scavengers in vivo, thereby ameliorating oxidative damage associated with inflammatory diseases.

Thermophysical properties and reaction kinetics of γ–irradiated poly allyl diglycol carbonates nuclear track detector

Kinetic thermogravimetric technique was used to study the effect of gamma irradiation on the poly allyl diglycol carbonates (PADC) within the dose range from 50 to Gy. The approach of Coats-Redfern was used to analyze the data. Results showed that low doses around 50 Gy make the polymer slightly more resistive to heat treatment. Higher radiation doses cause severe effects in the samples accompanied by the formation of lower molecular mass species and consequent crosslinking. Results support the domination of re-polymerization and crosslinking for the γ radiation interaction PADC at dose below about Gy, while the situation is inverted above Gy in which chain secession dominates.

Detection of Labile Low-Molecular-Mass Transition Metal Complexes in Mitochondria.

Liquid chromatography was used with an online inductively coupled plasma mass spectrometer to detect low-molecular-mass (LMM) transition metal complexes in mitochondria isolated from fermenting yeast cells, human Jurkat cells, and mouse brain and liver. These complexes constituted 20-40% of total mitochondrial Mn, Fe, Zn, and Cu ions. The major LMM Mn complex in yeast mitochondria, called Mn1100, had a mass of ∼1100 Da and a concentration of ∼2 μM. Mammalian mitochondria contained a second Mn species with a mass of ∼2000 Da at a comparable concentration. The major Fe complex in mitochondria isolated from exponentially growing yeast cells had a mass of ∼580 Da; the concentration of Fe580 in mitochondria was ∼100 μM. When mitochondria were isolated from fermenting cells in postexponential phase, the mass of the dominant LMM Fe complex was ∼1100 Da. Upon incubation, the intensity of Fe1100 declined and that of Fe580 increased, suggesting that the two are interrelated. Mammalian mitochondria contained Fe580 and two other Fe species (Fe2000 and Fe1100) at concentrations of ∼50 μM each. The dominant LMM Zn species in mitochondria had a mass of ∼1200 Da and a concentration of ∼110 μM. Mammalian mitochondria contained a second major LMM Zn species at 1500 Da. The dominant LMM Cu species in yeast mitochondria had a mass of ∼5000 Da and a concentration in yeast mitochondria of ∼16 μM; Cu5000 was not observed in mammalian mitochondria. The dominant Co species in mitochondria, Co1200, had a concentration of 20 nM and was probably a cobalamin. Mammalian but not yeast mitochondria contained a LMM Mo species, Mo730, at a concentration of ∼1 μM. Increasing Mn, Fe, Cu, and Zn concentrations 10-fold in the medium increased the concentration of the same element in the corresponding isolated mitochondria. Treatment with metal chelators confirmed that these LMM species were labile. The dominant S species at 1100 Da was not free glutathione or glutathione disulfide.

Tumor-derived α-fetoprotein impairs the differentiation and T cell stimulatory activity of human dendritic cells.

Several tumor-derived factors have been implicated in dendritic cell (DC) dysfunction in cancer patients. α-fetoprotein (AFP) is an oncofetal Ag that is highly expressed in abnormalities of prenatal development and several epithelial cancers, including hepatocellular carcinoma (HCC). In HCC patients exhibiting high levels of serum AFP, we observed a lower ratio of myeloid/plasmacytoid circulating DCs compared with patients with low serum AFP levels and healthy donors. To test the effect of AFP on DC differentiation in vitro, peripheral blood monocytes from healthy donors were cultured in the presence of cord blood-derived normal AFP (nAFP) or HCC tumor-derived AFP (tAFP), and DC phenotype and function were assessed. Although the nAFP and tAFP isoforms only differ at one carbohydrate group, low (physiological) levels of tAFP, but not nAFP, significantly inhibited DC differentiation. tAFP-conditioned DCs expressed diminished levels of DC maturation markers, retained a monocyte-like morphology, exhibited limited production of inflammatory mediators, and failed to induce robust T cell proliferative responses. Mechanistic studies revealed that the suppressive activity of tAFP is dependent on the presence of low molecular mass (LMM) species that copurify with tAFP and function equivalently to the LMM fractions of both tumor and nontumor cell lysates. These data reveal the unique ability of tAFP to serve as a chaperone protein for LMM molecules, both endogenous and ubiquitous in nature, which function cooperatively to impair DC differentiation and function. Therefore, novel therapeutic approaches that antagonize the regulatory properties of tAFP will be critical to enhance immunity and improve clinical outcomes.

Determination of Prostate-Specific Antigen in Serum and a Reference Material by On-Chip Immunoaffinity Chromatography

Glycoprotein tumor markers are striking examples of heterogeneous analytes. The complexity of their structural forms in biological fluids is generally not reflected in reference materials. Therefore, they are not specified to consist of a distinct form, but rather to contain a mixture of molecular species. In this study, the question of the heterogeneity of free prostate-specific antigen (free PSA) is addressed in reference materials to define the immunoreactive molecular species and compare them to those in clinical serum. The reference material for free PSA and serum samples of subjects with benign prostatic hyperplasia and prostate cancer was examined for immunoreactivity to epitope I-specific anti-free PSA antibody using on-chip immunoaffinity chromatography in combination with mass spectrometry for the determination of bound forms. The mass spectra of the reference material for free PSA and clinical serum, obtained by on-chip immunoaffinity chromatography, were similar. The cluster of major free PSA-immunoreactive peaks at 28–29 kDa corresponding to the mature glycosylated PSA molecule overlapped in both analytes. However, the reference material displayed a more restricted pattern of low molecular mass species corresponding to nicked PSA fragments or PSA degradation products. The PSA concentration in clinical serum seems to consist of more species than equivalent concentrations of reference material. Regarding analysis of heterogeneous proteins, immunoaffinity capture combined with mass-specific detection represents a rapid means for selective detection of distinct molecular species, exceeding the analytical performance of current formats of immunoassays.

High-performance liquid chromatographic and mass spectrometric analysis of fluorescent carbon nanodots

Amino/hydroxyl-functionalized fluorescent carbon nanodots (C-NanoD) are conveniently synthesized based on hydrothermal carbonization of chitosan at 180°C. Dialysis membranes with small cut-off masses (500–1000Da) were found useful for removing the side-products and low molecular mass species to purify the C-NanoD product. Herein, reversed-phase high-performance liquid chromatography (RP-HPLC) has been successfully applied to fractionate the C-NanoD product. The elution order of the C-NanoD species present in the sample follows approximately their core sizes from small to large. The separated C-NanoD fractions are collected and characterized by UV absorption spectroscopy, photoluminescence (PL) spectroscopy, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), and transmission electron microscopy (TEM). All the C-NanoD fractions display a distinctive absorption band at 300nm, attributing to the n→π⁎ transition of CO bond. The PL spectra of the fractions display emission peaks at 400–415nm which are slightly red-shifted with their increase in relative molecular masses. The C-NanoD fractions are fully anatomized by MALDI-TOF MS, displaying their fragmentation mass ion features. The core sizes of some selected C-NanoD are determined as 1.6, 1.8, 2.5, and 3.1nm by TEM which are in consistent with their HPLC elution order. The findings highlight the virtues of RP-HPLC to fractionate and reveal the unique characteristics of individual C-NanoD species present in an as-synthesized C-NanoD product which may have potential applications in the fields of bioanalysis, bioimaging, catalysis, chemosensing, energy storage, and optoelectronics device.

Metallomics for drug development: a further insight into intracellular activation chemistry of a ruthenium(iii)-based anticancer drug gained using a multidimensional analytical approach

The mechanism by which the most relevant ruthenium anticancer drugs are activated in tumors to commence their tumor-inhibiting action remains one of the challenging research tasks of present-day metallomics. This contribution aims to capture and identify eventually more reactive species of one of two bis-indazole tetrachloridoruthenate(III) compounds that are progressing in clinical trials. In view of the fact that the transport of ruthenium into cancer cells is governed by transferrin receptors, the susceptibility of the Ru drug adduct with holo-transferrin to exposure by glutathione and ascorbic acid (at their cancer cytosol concentrations) was studied by inductively coupled plasma mass spectrometry (ICP-MS), following isolation of the reaction products by ultrafiltration. Next, capillary electrophoresis coupled to ICP-MS was applied to monitor changes in the Ru speciation both under simulated cancer cytosol conditions and in real cytosol and to assign the charge state of novel metal species. The latter were identified by using tandem electrospray ionization MS in the respective ion mode. The formation of ruthenium(II) species was for the first time revealed, in which the central metal is coordinated by the reduced (GSH) or the oxidized (GSSG) form of glutathione, i.e. [Ru(II)HindCl4(GSH)](2-) and [Ru(II)HindCl4(GSSG)](2-), respectively (Hind = indazole). Ascorbic acid released the ruthenium functionality from the protein-bound form in a different way, the products of adduct cleavage containing aqua ligands. Distribution of low-molecular mass species of Ru in human cytosol was found to have very much in common with the ruthenium speciation assayed under simulated cytosol conditions.

Study of nickel content in Ni-rich food products in Slovenia

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 3000Da) 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.

Infrared Spectroscopic Study of the Thermo-Oxidative Aging of Polyethylene Containing Pro-Oxidant

Synthetic polymers are not normally biodegradable until they are degraded into low molecular mass species that can be assimilated by microorganisms. This means that biodegradation must be preceded by an abiotic degradation that produces monomeric and oligomeric products. It has been shown that carboxylic acids, alcohols, ketones, etc... can be utilized by microorganisms as nutrients to produce cell biomass. Polyethylene is resistant to oxidation and biodegradation because of the presence of antioxidants and stabilizers. However, it can be made oxo-biodegradable by the use of prooxidant additives. The most active prooxidants are those based on transition metal particulary Fe, Co and Mn. This study is an attempt to investigate the effect of prooxidant additives on the thermo-oxidation of polyethylene. Three differentes mulch films of polyethylene, two films with prooxidant additives consisting of salt based on cobalt and iron and the third film whitout prooxidant, were subjected to thermo-oxidative degradation which was conducted in an air oven at 70°C that normally occur during composting conditions, for extended time periods. Based on Fourier transform infrared spectroscopy the chemical and structural changes induced by this exposure were followed by monitoring the changes in carbonyl index and cristallinity. The results reveal an increase in the carbonyl groups with aging time more important for the polyehylene films containing a combination of Fe and Co additives than these obtained by the films with only one transition metal additive (Co) while the LDPE without additives represents no increase in carbonyl groups. The results show also a small variation of cristallinity for the two differents polyethylene films with pro-oxidant. This indicates that the transition metal prooxidant plays an important role in the degradation of PE films and accelerates the degradation of PE.

Environmental impact assessment of radionuclide and metal contamination at the former U site at Kadji Sai, Kyrgyzstan

During 1949–1967, a U mine, a coal-fired thermal power plant and a processing plant for the extraction of U from the produced ash were operated at the Kadji Sai U mining site in Tonsk district, Issyk-Kul County, Kyrgyzstan. The Kadji Sai U legacy site represents a source of contamination of the local environment by naturally occurring radionuclides and associated trace elements. To assess the environmental impact of radionuclides and trace metals at the site, field expeditions were performed in 2007 and 2008 by the Joint collaboration between Norway, Kazakhstan, Kyrgyzstan, Tajikistan (JNKKT) project and the NATO SfP RESCA project. In addition to in situ gamma and Rn dose rate measurements, sampling included at site fractionation of water and sampling of water, fish, sediment, soils and vegetation. The concentrations of radionuclides and trace metals in water from Issyk-Kul Lake were in general low, but surprisingly high for As. Uptake of U and As was also observed in fish from the lake with maximum bioconcentration factors for liver of 1.6 and 75, respectively. The concentrations of U in water within the Kadji Sai area varied from 0.01 to 0.05 mg/L, except for downstream from the mining area where U reached a factor of 10 higher, 0.2 mg/L. Uranium concentrations in the drinking water of Kadji Sai village were about the level recommended by the WHO for drinking water. The 234U/238U activity ratio reflected equilibrium conditions in the mining pond, but far from equilibrium outside this area (reaching 2.3 for an artesian well). Uranium, As and Ni were mainly present as low molecular mass (LMM, less than 10 kDa) species in all samples, indicating that these elemental species are mobile and potentially bioavailable.The soils from the mining sites were enriched in U, As and trace metals. Hot spots with elevated radioactivity levels were easily detected in Kadji Sai and radioactive particles were observed. The presence of particles carrying significant amount of radioactivity and toxic trace elements may represent a hazard during strong wind events (wind erosion). Based on sequential extractions, most of the elements were strongly associated with mineral matter, except for U and As having a relatively high remobilization potential. Low Kd was obtained for U (3.5 × 102 L/kg d.w.), intermediate Kds (∼3 × 103 L/kg d.w.) were obtained for 226Ra, As and Ni, while a high Kd (2.2 × 105 L/kg d.w.) were obtained for Pb. The accumulation of metals in fish gills reflected the LMM species in the Issyk-Kul water, and did not show any bioaccumulation. The muscle Hg concentrations in all fish species were low and did not represent any health risk even for groups at risk.Total gamma and Rn dose rate to man amounted to about 12 mSv/y, while the highest calculated dose rate for non-human species based on the ERICA Assessment Tool were obtained in terrestrial plants (164 μGy/h) due to the Ra exposure. The results obtained showed that radiation doses to resident public at all of the investigated sites in the Kadji Sai area were in general relatively low. Low radiological risk and no detrimental health impact on resident public can be expected at these sites. However, exposure to Rn and Tn in the living environment can be further reduced by implementing simple countermeasures such as ventilation of dwelling cellars. More focus in the Kadji Sai area should probably be put on trace elements, especially the As uptake in fish in Lake Issyk-Kul.

SEPARATION OF GALACTOGLUCOMANNANS, LIGNIN, AND LIGNIN-CARBOHYDRATE COMPLEXES FROM HOT-WATER-EXTRACTED NORWAY SPRUCE BY CROSS-FLOW FILTRATION AND ADSORPTION CHROMATOGRAPHY

A simple method to simultaneously recover polymeric carbohydrates, mainly galactoglucomannans (GGM), lignin, and lignin-carbohydrate complex (LCC) from hot-water-extracted Norway spruce wood is presented. The isolation method consists of cross-flow filtration, where high and low molecular mass species are removed, followed by fixed-bed adsorption on a hydrophobic polymeric resin (XAD-16) to remove lignins and lignans. In the second step of fixed-bed adsorption, a phenylic reversed-phase analytical chromatography column, where mass transport resistance is minimized and a very high selectivity towards aromatic compounds have been observed, was used to separate LCC from GGM. The isolated LCC fraction contained about 10% aromatics, whereas the upgraded GGM fraction contained about 1.5% aromatics and the lignin fraction contained about 56% aromatics. Polymeric xylan was accumulated in the GGM fraction, while mannose was the dominant sugar found in the LCC fraction. As products, approximately 7% was recovered in the lignin fraction in the first adsorptive step, 5% was recovered as LCC, and 88% as upgraded hemicelluloses.

Environmental impact assessment of radionuclides and trace elements at the Kurday U mining site, Kazakhstan

The Kurday uranium mining site in Kazakhstan operated from 1954 to 1965 as part of the USSR nuclear weapon programme. To assess the environmental impact of radionuclides and trace elements associated with the Kurday mining site, field expeditions were performed in 2006. In addition to in situ gamma and 220Rn dose rate measurements, sampling included at site fractionation of water as well as sampling of water, fish, sediment, soils and vegetation. The concentrations of U and associated trace metals were enriched in the Pit Lake and in the artesian water (U exceeding the WHO guideline value for drinking water), and decreased downstream from the mining area. Uranium, As, Mo and Ni were predominantly present as mobile low molecular mass species in waters, while a significant proportion of Cr, Mn and Fe were associated with colloids and particles. Due to oxidation of divalent iron in the artesian ground water upon contact with air, Fe served as scavenger for other elements, and peak concentrations of U-, Ra-isotopes, As and Mn were seen. Most radionuclides and trace elements were contained in minerals in soils and sediments, and good correlations were obtained between U and As, Cd, Mo and 226Ra. Based on sequential extractions, a significant fraction of U, Pb and Cd could be considered mobile. Radioactive particles carrying significant amount of trace metals may represent a hazard during strong wind events. The transfer of radionuclides and metals from soils or sediments to water was in general low. The Kd levels varied with the element in question, ranging from 0.5 to 3 × 102 L/kg d.w. for 238U being relatively mobile, 103 for 226Ra, As, Cd, Ni, to 104 L/kg d.w. for Cu, Cr and Pb being rather inert The transfer of radionuclides and metals from soils to vegetation (TF) was low, while higher if the transfer to vegetation, especially underwater mosses, occurred via water (e.g., BCF 37 L/kg w.w. for 238U and 3 × 103 L/kg w.w. for 226Ra). The transfer of Cd, Pb and As from water to fish liver (BCF) was rather high, showing BCFs in the range of 102–103 L/kg w.w., and may, if eaten, represent a health risk. Furthermore, the high Hg level in fish filet reaching 0.3 mg/kg w.w. muscle and the tendency of biomagnification call for dietary restrictions. Total gamma and Rn dose rate to man amounted to about 6 mSv/y, while the highest calculated dose rate for non-human species based on the ERICA Assessment Tool were obtained in aquatic plants, with calculated mean doses of 700 μGy/hr, mostly due to the U exposure. Overall, it is concluded that measures such as restricted access to the Pit Lake as well as dietary restrictions with respect to drinking water and intake of fish should be taken to reduce the environmental risk to man and biota.

Environmental impact assessment of radionuclide and metal contamination at the former U sites Taboshar and Digmai, Tajikistan

Uranium (U) ore mining and processing were initiated in the former Soviet Republics of Tajikistan after the Second World War as part of the USSR nuclear weapon programme. The U mine in Taboshar was opened in 1936, and mining took place from 1945 to 1965, while the Digmai tailings dump was exploited during 1963–1993. The mining, milling and extraction activities have resulted in large amounts of waste rock deposits and U tailing materials placed in the vicinity of inhabited areas. To assess the environmental impact of radionuclides and trace metals in the Taboshar and Digmai mining and tailing sites in Tajikistan, field expeditions were performed in 2006 and 2008. In addition to in situ gamma and radon dose rate measurements, sampling of water, fish, sediments, soils and vegetation including in situ fractionation of water were performed. The U concentrations in water from Taboshar Pit Lake (2.0 mg U/L) were higher than in waters collected in the Digmai area. The Pit Lake and the stream water from the tailing mountain were also characterised by elevated concentrations of As, Mo, Mn and Fe, exceeding the WHO recommended values for drinking water. Uranium, As, Mo and Ni were present as low molecular mass species in the waters, and are therefore considered mobile and potentially bioavailable. The 238U concentrations in sediments and soils varied between the sites; with peak concentrations (6 kBq/kg dw) in sediments from the Pit Lake, while the soil concentrations were significantly lower (296–590 Bq/kg dw). In contrast, high levels of the radium isotopes (226Ra and 228Ra) were found in the Digmai soil (17–32 kBq/kg dw). Based on sequential extraction results, both U and Pb were found to be quite mobile at the Pit Lake site, showing that these elements were associated with the pH sensitive and redox sensitive amorphous fractions. In tailings, U was found to be quite mobile, but here Pb was rather inert. The transfer of radionuclides and metals from sediments to waters was in general low. In the Pit Lake, U was quite mobile (Kd = 90 L/kg), followed by Ni (1.5 × 103 L/kg) and As (6 × 103 L/kg), Cu and Cd (1.5 × 104 L/kg), while Pb (3 × 105 L/kg) was rather inert. The transfer from soil to plant, TFs (kg/kg dw), was in general low, while the bioconcentration factor for water living Poaceae and for fish from water was relatively high (Pb 1.8 × 105 and Cd 1 × 104). These legacy sites, containing enhanced levels of natural radioactive material (TENORM) as well as heavy metals, may represent a hazard having a potential radiological and chemical impact on man and the environment, and measures should be taken to reduce the environmental risk to man and biota.

The use of CIM-DEAE monolithic chromatography coupled to ICP-MS to study the distribution of cisplatin in human serum

Among platinum (Pt) containing chemotherapeutics, cisplatin (CDDP) is the most widely used. Its distribution in spiked human serum and serum of cancer patients was studied by liquid chromatography with UV and ICP-MS detection. Rapid Pt fractionation was performed by SEC on a HiTrap desalting column. The CIM DEAE-1 fast monolithic column was used in speciation analysis of CDDP for the first time. Complementary to monolithic chromatography, Pt speciation was also performed by FPLC on a strong anion-exchange Mono Q particle packed column. To study CDDP interactions with proteins, synthetic solutions of single standard proteins (albumin (HSA), transferrin (Tf) and γ-globulins (IgG)) or their mixtures, and human serum samples were spiked with CDDP and incubated at 37 °C for 24 h. Results of fractionation showed that more than 80% of Pt in serum was eluted with proteins and the remaining portion as low molecular mass species. Serum proteins were efficiently separated by anion-exchange chromatography on FPLC Mono Q or CIM DEAE-1 columns. Both complementary speciation procedures gave statistically comparable results. In spiked serum samples about 83 to 87% of Pt was eluted with HSA, 3 to 4.5% with Tf and the remaining 8.5 to 14%, which represents unbound CDDP, with a solvent front. The developed CIM-DEAE-1 fast monolithic chromatography procedure was applied to Pt speciation in serum of cancer patients receiving CDDP-based chemotherapy. In these samples Pt was found to be bound as follows: 87 to 93% to HSA, 2.6 to 6.4% to Tf, and 4.2 to 6.6% as unbound CDDP species.

Speciation of selected trace elements in three Ethiopian Rift Valley Lakes (Koka, Ziway, and Awassa) and their major inflows

The Ethiopian Rift Valley Lakes (ERVLs) are water resources which have considerable environmental, economic and cultural importance. However, there is an increasing concern that increasing human activities around these lakes and their main inflows can result in increased contamination of these water bodies. Information on total concentrations of some trace elements is available for these lakes and their inflows; however, data on the trace element speciation is lacking. Therefore, the objective of this study was to determine the low molecular mass (LMM) trace element species and also, evaluate the influence of flooding episodes on the LMM trace element fractions. At-site size and charge fractionation system was used for sampling of water from the lakes Koka, Ziway and Awassa and their main inflows during the dry and wet seasons. The results showed that chromium (Cr), manganese (Mn), cobalt (Co), nickel (Ni), copper (Cu), zinc (Zn), and lead (Pb) in Lake Koka and its inflows as well as in Lake Ziway were predominantly present as HMM (high molecular mass, i.e., > 10 kDa) forms, while arsenic (As), selenium (Se), cadmium (Cd) were more mobile during the dry season. In Lake Awassa, all except Cr and Mn were predominantly found as LMM species (low molecular mass, i.e. < 10 kDa) which can be attributed to the high concentrations of LMM DOC (dissolved organic carbon). During the wet season, results from the Lake Koka and its inflows showed that all trace elements were predominantly associated with HMM forms such as colloids and particles, demonstrating that the mobility of elements was reduced during the wet season. The colloidal fraction of elements such as Cr, Ni, and Cd was also correlated with dissolved Fe. As the concentration of LMM trace element species are very low, the mobility, biological uptake and the potential environmental impact should be low.

Degradation as a result of UV radiation of bloodmeal-based thermoplastics

Polymers are known for their susceptibility to degradation as a result of ultra-violet (UV) radiation. In this study, the UV stability of bloodmeal-based thermoplastics (BMT) was evaluated over a period of 12 weeks. Formulations with and without plasticiser were tested and moisture was excluded during accelerated weathering to isolate the effect of UV because of the material’s known sensitivity to moisture. It was found that embrittlement due to loss of water overshadowed the effect of UV degradation. Embrittlement caused the material’s toughness to be reduced by an order of magnitude after only two weeks of exposure, for either plasticised or unplasticised samples. An initial increase in tensile strength was observed after two weeks followed by a steady decline in strength. The elastic modulus reached a plateau after about two weeks of exposure. FTIR did not confirm any chemical changes after 12 weeks exposure and TGA suggested that low molecular mass species were quickly lost during the course of the test. The absence of chemical changes does not suggest resistance to environmental degradation, although the dark pigmentation of bloodmeal may have contributed to the lack of UV degradation. Embrittlement remains a greater concern and requires further attention.

Rapid fractionation of Al in human serum by the use of HiTrap desalting size exclusion column with ICP-MS detection

To understand the pathways of Al transport 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.