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  • 1.
    Danielsson, Conny
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Analysis of PCDD/Fs in fly ash using comprehensive two-dimensional gas chromatography with electron capture detection (GC×GC-µECD)2005In: Organohalogen Compounds, Vol. 67, 103-6 p.Article in journal (Refereed)
  • 2.
    Danielsson, Conny
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Korytár, Peter
    de Boer, Jacob
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Trace Analysis of PCDD/Fs and WHO-PCBs in Food and Feed Using Comprehensive Two-Dimensional Gas Chromatography (GCxGC)2003In: Organohalogen Compounds, Vol. 60, 395-8 p.Article in journal (Refereed)
  • 3.
    Danielsson, Conny
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Korytárb, Peter
    Bergek, Sture
    Umeå University, Faculty of Science and Technology, Chemistry.
    Brinkman, Udo A.Th.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Trace analysis of polychlorinated dibenzo-p-dioxins, dibenzofurans and WHO polychlorinated biphenyls in food using comprehensive two-dimensional gas chromatography with electron-capture detection2005In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1086, no 1-2, 61-70 p.Article in journal (Refereed)
    Abstract [en]

    Trace analysis of 2,3,7,8-polychlorinated dibenzo-p-dioxins (PCDDs), dibenzofurans (PCDFs) and the 12 WHO-PCBs (four non-ortho and eight mono-ortho congeners that have been assigned toxic equivalence factors, TEFs, by the World Health Organisation) was conducted by comprehensive two-dimensional gas chromatography with a micro electron-capture detector (GC x GC-mu ECD). Four food matrices (fish oil from herring, spiked cows' milk, vegetable oil and an eel extract) were analysed by two GC x GC laboratories, and four GC-HRMS laboratories generated reference values. The two GC x GC laboratories used different column combinations for separating the target analytes. For the first dimension, non-polar DB-XLB and VF-1 columns were used, and for the second dimension, an LC-50 liquid crystalline column with unique selectivity for planar compounds. The congener-specific and total toxic equivalence (TEQ) data obtained using DB-XLB x LC-50 were in good agreement with results obtained by the GC-HRMS laboratories. The WHO-PCB data obtained with the VF-1 x LC-50 combination was also good, but the PCDD/F concentrations were sometimes overestimated due to matrix interferences. GC x GC-mu ECD using DB-XLB x LC-50 seems to fulfil the European Community requirements of a screening method for PCDD/F and WHO-PCB TEQ in food.

  • 4.
    Haglund, Peter
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Korytar, Peter
    de Boer, Jacob
    Validation of GC×GC-ECD for the determination of dioxins and dioxin-like PCBs in food and feed2005In: Organohalogen Compounds, Vol. 67, 99-102 p.Article in journal (Refereed)
  • 5.
    Haglund, Peter
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Harju, Mikael
    Umeå University, Faculty of Science and Technology, Chemistry.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Marriott, Philip
    Effects of temperature and flow regulated carbon dioxide cooling in longitudinally modulated cryogenic systems for comprehensive two-dimensional gas chromatography2002In: Journal of Chromatography A, Vol. 962, no 1-2, 127-34 p.Article in journal (Refereed)
    Abstract [en]

    Two different modes of temperature regulation in longitudinally modulated cryogenic systems (LMCSs) for comprehensive two-dimensional gas chromatography (GC×GC) were compared. Carbon dioxide was used as coolant. In the first mode of operation, the temperature of the trap was regulated to a pre-set temperature using a digital temperature controller (“the constant temperature mode”). In the second, the temperature was regulated to a fixed negative offset to the oven temperature by using a constant flow of CO2 (“the constant flow mode”). A number of problems were occasionally observed using the constant temperature mode: (1) severe band broadening of high boiling analytes in the second dimension; (2) non-Gaussian reconstructed first-dimension peak profiles; (3) high background due to modulation of first-dimension column bleed. It was concluded that these problems were associated with inefficient solute remobilization at low LMCS trap temperatures (1 and 2) or large trap temperature fluctuations (3). These problems could be avoided or significantly reduced by using the constant flow mode. Best results were obtained as the trap temperature was kept about 70 °C below the oven temperature.

  • 6.
    Haglund, Peter
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Korytár, Peter
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Diaz, Jordí
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Chemistry.
    Leonards, Pim
    Brinkman, Udo
    de Boer, Jacob
    GCxGC-ECD a promising method for the determination of dioxins and dioxin-like PCBs in food and feed2008In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642 (Print) 1618-2650 (Online), Vol. 390, no 7, 1815-27 p.Article in journal (Refereed)
    Abstract [en]

    There is a need for cost-efficient alternatives to gas chromatography (GC)–high-resolution mass spectrometry (HRMS) for the analysis of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) and dioxin-like polychlorinated biphenyls (PCBs) in food and feed. Comprehensive two-dimensional GC–micro electron capture detection (GC×GC-μECD) was tested and all relevant (according to the World Health Organisation, WHO) PCDD/Fs and PCBs could be separated when using a DB-XLB/LC-50 column combination. Validation tests by two laboratories showed that detectability, repeatability, reproducibility and accuracy of GC×GC-μECD are all statistically consistent with GC-HRMS results. A limit of detection of 0.5 pg WHO PCDD/F tetrachlorodibenzo-p-dioxin equivalency concentration per gram of fish oil was established. The reproducibility was less than 10%, which is below the recommended EU value for reference methods (less than 15%). Injections of vegetable oil extracts spiked with PCBs, polychlorinated naphthalenes and diphenyl ethers at concentrations of 200 ng/g showed no significant impact on the dioxin results, confirming in that way the robustness of the method. The use of GC×GC-μECD as a routine method for food and feed analysis is therefore recommended. However, the data evaluation of low dioxin concentrations is still laborious owing to the need for manual integration. This makes the overall analysis costs higher than those of GC-HRMS. Further developments of software are needed (and expected) to reduce the data evaluation time. Combination of the current method with pressurised liquid extraction with in-cell cleanup will result in further reduction of analysis costs.

  • 7.
    Haglund, Peter
    et al.
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Wiberg, Karin
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Nording, Malin
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Björklund, Erland
    Lunds universitet.
    Sporring, Sune
    Lunds universitet.
    Hyphenated techniques for dioxin analysis: LC-LC-GC-ECD, GCxGC-ECD, and selective PLE with GC-HRMS or bioanalytical detection2004In: Organohalogen Compounds, Vol. 66, 376-382 p.Article in journal (Refereed)
  • 8.
    Harju, Mikael
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Comprehensive two-dimensional gas chromatography of the 209 polychlorinated biphenyls2003In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1019, no 1-2, 111-126 p.Article in journal (Refereed)
    Abstract [en]

    Comprehensive two-dimensional gas chromatography (GC×GC) of the 209 polychlorinated biphenyls (CBs) was carried out using a longitudinally modulated cryogenic system (LMCS) and liquid carbon dioxide as cryogen. The effluent from a non-polar column was modulated and further separated on either a polar or a shape-selective second-dimension column. Five GC×GC column combinations were evaluated, with DB-XLB as the first column in each case. DB-XLB separates more congeners than any other GC column currently available. When combined with a biscyanopropyl siloxane (SP-2340 or BPX70) or smectic liquid crystal (LC-50) second-dimension column in a GC×GC system many additional CBs can be separated. In total, 176 and 181 of the 209 congeners were separated (Rs=0.5) on the column combinations DB-XLB/SP-2340 and DB-XLB/LC-50, respectively. Of the 136 CBs present in any Aroclor mixture at concentrations greater than 0.05% (w/w), 126 were resolved using either of these two column combinations. The seven frequently measured CBs 28, 52, 101, 118, 138, 153, 180, and the WHO-PCBs 77, 81, 105, 114, 118, 123, 126, 156, 157, 167, 169 and 189 were all separated from Aroclor CBs on the DB-XLB/LC-50 column set, whereas CBs 118 and 131 coeluted on the DB-XLB/SP-2340 column set. In addition, three technical CB formulations (Aroclors 1232, 1248 and 1260) and a seal blubber sample (Halichoerus grypus) from the Baltic Sea were analyzed. Similar peak patterns were found for Aroclor 1260 and the CBs in the seal blubber, facilitating use of this technical CB formulation to identify the CBs in the blubber by GC×GC. Individual CBs in environmental samples, such as seal blubber, may be identified semi-automatically by matching the samples GC×GC profiles to a template generated using a standard containing all 209 CBs. Using such a template, 64 CBs were identified in the grey seal blubber sample.

  • 9. Korytár, P
    et al.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    Leonards, P E G
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Department of Chemistry.
    de Boer, J
    Brinkman, U A Th
    Separation of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like polychlorinated biphenyls by comprehensive two-dimensional gas chromatography with electron-capture detection2004In: Journal of Chromatography A, ISSN 0021-9673, E-ISSN 1873-3778, Vol. 1038, no 1-2, 189-199 p.Article in journal (Refereed)
    Abstract [en]

    Comprehensive two-dimensional gas chromatography (GC×GC) with electron-capture detection (ECD) has been optimized for the separation of seventeen 2,3,7,8-substituted polychlorinated dibenzo-p-dioxins and dibenzofurans and 12 dioxin-like polychlorinated biphenyls, with emphasis on the selection of the first- and second-dimension, commercially available, columns. When eight second-dimension columns were subsequently combined with a 100% methylpolysiloxane stationary phase (DB-1) in the first dimension to create orthogonal conditions, a complete separation of all congeners with different TEF values was obtained with two column combinations, DB-1 × VF-23 and DB-1 × LC-50. When other types of first-dimension columns were used (and orthogonality was partly sacrificed), a DB-XLB column combined with 007-65HT, VF-23 and LC-50 was found to provide a complete separation of all 29 priority congeners. Next, the potential of these three column combinations for real-life analysis was preliminarily studied. With a spiked and fractionated milk extract, DB-XLB × LC-50 was found to be the most powerful column combination, because of the good separation of the 29 priority congeners from each other as well as from the matrix constituents. Quantitative performance (close to three-order linearity; LODs, 30–150 fg injected; R.S.D.s, 1.5–6.5% (n=10)) was satisfactory.

  • 10. Kristenson, E Maria
    et al.
    Korytár, Peter
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Kallio, Minna
    Brandt, Menno
    Mäkelä, Jani
    Vreuls, René J J
    Beens, Jan
    Brinkman, Udo A Th
    Evaluation of modulators and electron-capture detectors for comprehensive two-dimensional GC of halogenated organic compounds2003In: Journal of Chromatography A, Vol. 1019, no 1-2, 65-77 p.Article in journal (Refereed)
    Abstract [en]

    Abstract

    Different cryogenic and a heated GC×GC modulator(s) were evaluated and compared for the analysis of high-boiling halogenated compounds. The cryogenic modulators investigated were: (i) the longitudinally modulated cryogenic system; (ii) the liquid-nitrogen-cooled jet modulator (KT2001); (iii) a dual-jet CO2 modulator (made in-house); (iv) a semi-rotating cryogenic modulator (made in-house) and (v) a CO2 loop modulator (KT2003); the heated modulator was the slotted heater system (sweeper). Each modulator was optimised with respect to analyte peak widths at half height in the second-dimension. n-Alkanes, chlorinated alkanes, polychlorinated biphenyls (PCBs) and fluorinated polycyclic aromatic hydrocarbons (F-PAHs) were used as test analytes. The flow rate of the coolant was found to be an important parameter, i.e. the flow rate of the gaseous nitrogen in the KT2001, and of the liquid CO2 in the other cryogenic modulators. For the slotted heater the stroke velocity and pause time were important parameters. This modulator had a limited application range in terms of temperature due to a necessary 100 °C difference between sweeper and oven temperature. All cryogenic modulators were found to be suitable for the GC×GC analysis of high-boiling compounds, but the CO2 modulators are to be preferred to the KT2001 due to a wider application range and slightly narrower peaks. As regards the performance of three commercially available electron-capture detectors (ECDs), the aim was to obtain narrow peak widths in GC×GC, i.e. to avoid band broadening caused by the cell volume. The most important parameters were the flow rate of the make-up gas and the detector temperature which both should be as high as possible. Comparison of analyte peak widths obtained with ECD mode and flame ionisation detection (FID) showed that all ECDs exhibited band broadening compared to the FID. The narrowest peaks were obtained with the Agilent micro-ECD, which has a cell volume of only 150 μl.

  • 11.
    Spinnel, Erik
    et al.
    Umeå University, Faculty of Science and Technology, Chemistry.
    Danielsson, Conny
    Umeå University, Faculty of Science and Technology, Chemistry.
    Haglund, Peter
    Umeå University, Faculty of Science and Technology, Chemistry.
    Rapid and cost-effective analysis of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in soil, fly ash and sediment certified reference materials using pressurized liquid extraction with an integrated carbon trap.2008In: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 390, no 1, 411-417 p.Article in journal (Refereed)
    Abstract [en]

    Pressurized liquid extraction with an integrated carbon trap (PLE-C) has recently been developed for fast and efficient analysis of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) in food and feed. The method has also been tested, but not verified, for use on more complex soil samples, such as soil, sediment and fly ash. Hence, the primary aim of this study was to verify that PLE-C can produce reliable data for PCDDs/PCDFs in various abiotic matrixes. A second aim was to find a replacement for the previously used AX21 active carbon that is currently not commercially available. The performance of the PLE-C was evaluated using both single congener concentrations and toxic equivalency potentials (TEQ-pot) of three (soil, sediment and fly ash) certified reference materials. The results clearly show that PLE-C can be used for abiotic samples and that a commercially available carbon (Norit SA 4PAH HF) can replace the AX-21 carbon in the carbon trap. The TEQ-pot values obtained for the soil and sediment samples were within the uncertainty limits of the corresponding certified values, as were the determinations of single congener concentrations. PLE-C therefore has great potential for determination of PCDDs/PCDFs in soil and sediment samples. The TEQ-pot result for the fly ash was slightly lower than the certified TEQ-pot value, but it is still within the uncertainty limits of the certified value. Out of the single congener concentrations all but four (out of 17) agreed well with the values. Hence, PLE-C may potentially be used also for fly ash-after slight modifications. The integrated PLE-C and cleanup procedure is less labour-intensive than traditional methods such as Soxhlet extraction followed by a multistep cleanup, and consumes smaller quantities of ultrapure solvents than the commonly used Power-Prep system. In addition, PLE-C is capable of larger sample throughputs than the conventional methods. Thus, PLE-C is a promising alternative to the currently used sample preparation procedures for dioxins in abiotic samples. Figure PLE with integraded carbon trap for rapid PCDD/Fs analysis.

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