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  • 101.
    Schwalfenberg, Gerry
    et al.
    University of Alberta.
    Genuis, Stephen J.
    University of Alberta.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    The benefits and risks of consuming brewed tea: Beware of toxic element contamination2013In: Journal of Toxicology, ISSN 1687-8191, E-ISSN 1687-8205, Vol. 2013, article id 370460Article in journal (Refereed)
    Abstract [en]

    Background. Increasing concern is evident about contamination of foodstuffs and natural health products. Methods. Common off-the-shelf varieties of black, green, white, and oolong teas sold in tea bags were used for analysis in this study. Toxic element testing was performed on 30 different teas by analyzing (i) tea leaves, (ii) tea steeped for 3-4 minutes, and (iii) tea steeped for 15-17 minutes. Results were compared to existing preferred endpoints. Results. All brewed teas contained lead with 73% of teas brewed for 3 minutes and 83% brewed for 15 minutes having lead levels considered unsafe for consumption during pregnancy and lactation. Aluminum levels were above recommended guidelines in 20% of brewed teas. No mercury was found at detectable levels in any brewed tea samples. Teas contained several beneficial elements such as magnesium, calcium, potassium, and phosphorus. Of trace minerals, only manganese levels were found to be excessive in some black teas. Conclusions. Toxic contamination by heavy metals was found in most of the teas sampled. Some tea samples are considered unsafe. There are no existing guidelines for routine testing or reporting of toxicant levels in "naturally" occurring products. Public health warnings or industry regulation might be indicated to protect consumer safety.

  • 102.
    Stenberg, Anna
    et al.
    Luleå tekniska universitet.
    Andren, Henrik
    Malinovskiy, Dmitry
    Engström, Emma
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Rodushkin, Ilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Baxter, Douglas
    Isotopic variations of Zn in biological materials2004In: Analytical Chemistry, ISSN 0003-2700, E-ISSN 1520-6882, Vol. 76, no 14, p. 3971-3978Article in journal (Refereed)
    Abstract [en]

    Variations in the isotopic composition of Zn present in various biological materials were determined using high-resolution multicollector inductively coupled plasma mass spectrometry (MC-ICPMS), following digestion and purification by anion exchange chromatography. To correct for differences in instrumental mass discrimination effects between samples and standards, Cu was employed as an elemental spike. Complementary analyses of Zn separates by sector field ICPMS instruments revealed that the concentrations of the majority of potentially interfering elements were reduced to negligible levels. Residual spectral interferences resulting from 35Cl16O2+, 40Ar14N2+, and 40Ar14N16O+ could be instrumentally resolved from the 67Zn, 68Zn, and 70Zn ion beams, respectively, during measurement by MC-ICPMS. The only other observed interference in the Cu and Zn mass range that could not be effectively eliminated by high-resolution multicollection resulted from 35Cl2+, necessitating modification of the sample preparation procedure to allow accurate 70Zn detection. Complete duplication of the entire analytical procedure for human whole blood and hair, as well as bovine liver and muscle, provided an external reproducibility of 0.05-0.12” (2) for measured 66/64Zn, 67/64Zn, and 68/64Zn values, demonstrating the utility of the method for the precise isotopic analysis of Zn in biological materials. Relative to the selected Zn isotopic standard, 66/64Zn values for biological samples varied from -0.60” in human hair to +0.56” in human whole blood, identifying the former material as the isotopically lightest Zn source found in nature to date.

  • 103.
    Stenberg, Anna
    et al.
    Luleå tekniska universitet.
    Malinovskiy, Dmitry
    Rodushkin, Ilia
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andren, Henrik
    Ponter, Christer
    Analytica AB.
    Öhlander, Björn
    Baxter, Douglas
    Separation of Fe from whole blood matrix for precise isotopic ratio measurements by MC-ICP-MS: a comparison of different approaches2003In: Journal of Analytical Atomic Spectrometry, ISSN 0267-9477, E-ISSN 1364-5544, Vol. 18, no 1, p. 23-28Article in journal (Refereed)
    Abstract [en]

    Anion-exchange and precipitation procedures for Fe separation from unspiked human whole blood after microwave digestion and ashing decomposition techniques were thoroughly evaluated in terms of Fe recoveries, decreases in matrix element concentrations and elimination of interfering species for subsequent Fe isotope ratio measurements by multi-collector ICP-MS. During isotope ratio measurements involving 54Fe, 56Fe and 57Fe, on-line mass discrimination correction using Ni isotopes was applied, significantly reducing uncertainties both within and between Fe sample runs. Despite Fe recoveries below 100% for all separation procedures studied, no artificial isotope fractionation was detected. The degree of Fe fractionation in a commercially available, whole blood sample (Trace Elements in Whole Blood, Level 1, Sero AS), expressed as 56i (m2.83 - 0.06‰) and 57i (m4.23 - 0.08‰) values relative to IRMM-014 Fe isotopic reference material, agrees well with previously published data. Of the tested separation procedures, precipitation using NH3 was found to be the most rapid and cost-effective method, yielding high Fe recovery and low levels of concomitant elements.

  • 104.
    Stenberg, Anna
    et al.
    Luleå tekniska universitet.
    Malinovskiy, Dmitry
    Öhlander, Björn
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Andren, Henrik
    Forsling, Willis
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Sustainable Process Engineering.
    Engström, Lena-Maria
    Umeå universitet.
    Wahlin, Anders
    Umeå universitet.
    Engström, Emma
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Baxter, Douglas
    Measurement of iron and zinc isotopes in human whole blood: preliminary application to the study of HFE genotypes2005In: Journal of Trace Elements in Medicine and Biology, ISSN 0946-672X, E-ISSN 1878-3252, Vol. 19, no 1, p. 55-60Article in journal (Refereed)
    Abstract [en]

    Multi-collector inductively coupled plasma - sector field mass spectrometry was applied to the measurement of Fe and Zn isotopes in human whole blood samples. For the Fe present in the blood of healthy adults, enrichment of the lighter isotopes relative to a standard material was observed, in agreement with earlier studies. The level of fractionation was found to be lower in hemochromatosis patients exhibiting homozygous (C282Y/C282Y) mutation of the HFE gene. On the one hand, this reinforces the hypothesis that Fe fractionation in blood decreases with enhanced dietary absorption. On the other hand, this contradicts predictions made on the basis of determinations of Fe fractionation in blood samples collected from subjects characterized by milder HFE mutations. In healthy subjects, the Zn in blood is depleted in lighter isotopes, consistent with the limited number of prior observations. As for Fe, the Zn isotopic composition exhibited a tendency toward lower levels of fractionation in the blood of subjects with hereditary hemochromatosis with homozygous mutation (C282Y/C282Y) of the HFE gene. The results therefore suggest that both Fe and Zn isotopic signatures in whole blood, at least to some extent, reflect polymorphisms in the HFE gene.

  • 105.
    Ödman, Fredrik
    et al.
    Luleå tekniska universitet.
    Ruth, Thomas
    Analytica AB, Box 511, SE-183 25 Täby.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ponter, Christer
    Analytica AB.
    Validation of a field filtration technique for characterization of suspended particulate matter from freshwater: Part II. Minor, trace and ultra trace elements2006In: Applied Geochemistry, ISSN 0883-2927, E-ISSN 1872-9134, Vol. 21, no 12, p. 2112-2134Article in journal (Refereed)
    Abstract [en]

    A field filtration method for the concentration and separation of suspended particulate matter (SPM) from freshwater systems and the subsequent determination of minor, trace and ultra trace elements (As, Ba, Be, Cd, Co, Cr, Cs, Cu, Ga, Hf, Mo, Nb, Ni, Pb, Rb, Sb, Sc, Sn, Sr, Ta, Th, Tl, U, V, W, Zn and Zr) is validated with respect to detection limits, precision and bias. The validation comprises the whole procedure including filtration, sample digestion and instrumental analysis. The method includes two digestion procedures (microwave acid digestion and alkali fusion) in combination with inductively coupled plasma atomic emission spectrometry (ICP-AES) and inductively coupled plasma quadrupole mass spectrometry (ICP-QMS). Total concentrations of these 27 trace and minor elements have been determined in suspended particulate matter (SPM) from lake and river water with low levels of suspended solids (

  • 106. Österlund, Helene
    et al.
    Chlot, Sara
    Faarinen, Mikko
    ALS Laboratory Group, Luleå.
    Widerlund, Anders
    Rodushkin, Ilya
    Ingri, Johan
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Baxter, Douglas
    Simultaneous measurements of As, Mo, Sb, V and W using a ferrihydrite diffusive gradients in thin films (DGT) device2010In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 682, no 1-2, p. 59-65Article in journal (Refereed)
    Abstract [en]

    The ferrihydrite-backed DGT (diffusive gradients in thin films), recently developed for arsenic and phosphate measurements was, for the first time, characterized with respect to molybdate, antimonate, vanadate and tungstate determination. Arsenate was included in the characterization to allow comparison with literature data and thus provide quality control of the measurements. In addition to laboratory experiments, field measurements were carried out in a natural stream in northern Sweden affected by mine drainage. It was shown that ferrihydrite-DGT is suitable for simultaneous determination of labile arsenic, molybdate, antimonate, vanadate and tungstate over a wide pH range. Diffusion coefficients were estimated using two different methods; diffusion cell and direct uptake to DGT devices in synthetic solutions. Estimations of the coefficients using the direct uptake method were performed between pH 4 and 8. The results from the two methods agreed well irrespective of pH, except for molybdate and antimonate that showed decreased values at pH 8. Adsorption of the analytes to ferrihydrite gel discs was rapid at all pH values. However, there was a tendency toward lower adsorption affinity for antimonate compared to the other anions. 100% recovery of accumulated analytes was achieved through complete dissolution of the ferrihydrite adsorbent using 1.4 mol L-1 HNO3 with 0.1 mol L-1 HF. From field sampling it was concluded that the opportunities for accurate antimonate and molybdate determination decrease at pH ≥8.7. DGT labile concentrations were generally lower than dissolved concentrations. Relatively lower DGT concentrations, compared to dissolved (<0.45 μm), were observed under a period when ferric oxide precipitations were detected on the DGT protective filter.

  • 107.
    Österlund, Helene
    et al.
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Rodushkin, Ilya
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Geosciences and Environmental Engineering.
    Ylinenjärvi, Karin
    ALS Scandinavia AB.
    Baxter, Douglas
    Determination of total chlorine and bromine in solid wastes by sintering and inductively coupled plasma-sector field mass spectrometry2009In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 29, no 4, p. 1258-1264Article in journal (Refereed)
    Abstract [en]

    A sample preparation method based on sintering, followed by analysis by inductively coupled plasma-sector field mass spectrometry (ICP-SFMS) for the simultaneous determination of chloride and bromide in diverse and mixed solid wastes, has been evaluated. Samples and reference materials of known composition were mixed with a sintering agent containing Na2CO3 and ZnO and placed in an oven at 560 °C for 1 h. After cooling, the residues were leached with water prior to a cation-exchange assisted clean-up. Alternatively, a simple microwave-assisted digestion using only nitric acid was applied for comparison. Thereafter the samples were prepared for quantitative analysis by ICP-SFMS. The sintering method was evaluated by analysis of certified reference materials (CRMs) and by comparison with US EPA Method 5050 and ion chromatography with good agreement. Median RSDs for the sintering method were determined to 10% for both chlorine and bromine, and median recovery to 96% and 97%, respectively. Limits of detection (LODs) were 200 mg/kg for chlorine and 20 mg/kg for bromine. It was concluded that the sintering method is suitable for chlorine and bromine determination in several matrices like sewage sludge, plastics, and edible waste, as well as for waste mixtures. The sintering method was also applied for determination of other elements present in anionic forms, such as sulfur, arsenic, selenium and iodine.

123 101 - 107 of 107
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