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  • 1.
    Alsberg, T.
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Minten, J.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Haglund, J.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Törnqvist, M.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Determination of hydroxyalkyl derivatives of cobalamin (vitamin B12) using reversed phase high performance liquid chromatography with electrospray tandem mass spectrometry and ultraviolet diode array detection2001In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 15, no 24, p. 2438-45Article in journal (Refereed)
    Abstract [en]

    Electrospray ionization tandem mass spectrometry (ESI-MS/MS) and ultraviolet diode array detection (UV-DAD), coupled on-line to reversed phase high performance liquid chromatography (HPLC), was used for the characterization of hydroxyalkyl derivatives of cob(I)alamin. The reduced form of vitamin B12, cob(I)alamin, denoted a supernucleophile due to its high nucleophilic strength, has shown promise as an analytical tool in studies of electrophilically reactive compounds in vitro and in vivo. A method for analysis of DNA-phosphate adducts was developed earlier utilizing the supernucleophilicity of cob(I)alamin to transfer alkyl groups from the phosphotriester configuration in DNA, with the formation of a Co-substituted alkyl-cobalamin (alkyl-Cbl) complex. For the purpose of identification and quantification of alkyl-Cbls at high sensitivity, an MS/MS method has been developed with application to a number of 2-hydroxyalkyl-cobalamins (OHalkyl-Cbls). The precursor oxiranes were reacted with cob(I)alamin, followed by clean-up and mass spectrometric analysis of the resulting OHalkyl-Cbls. It was found that ionization was highly dependent on solvent composition. By using acetonitrile/water/trifluoroacetic acid (TFA) (eluent I), the base peak was the doubly protonated molecule [M + 2H](2+), whereas acetonitrile/water/1-methylpiperidine (eluent II) yielded the singly protonated molecule [M + H](+) as the base peak. Excellent separation was obtained with eluent II, with good separation between stereoisomers, thus enabling the characterization of these by means of UV spectra. Limits of quantitation for 2-hydroxypropyl-cobalamin (OHPr-Cbl) were 0.2 and 2 pg/microL (or 0.1 and 1 fmol/microL) using selected ion recording (SIR) with eluent I and II, respectively. The obtained detection level should be sufficient for analysis of alkyl-Cbls from a wide range of toxicological applications.

  • 2.
    Bergh, Caroline
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Torgrip, Ralf
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Östman, Conny
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Simultaneous selective detection of organophosphate and phthalate esters using gas chromatography with positive ion chemical ionization tandem mass spectrometry and its application to indoor air and dust2010In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 24, no 19, p. 2859-2867Article in journal (Refereed)
    Abstract [en]

    A selective and sensitive method for the simultaneous determination of 14 organophosphate and six phthalate esters using gas chromatography (GC) and mass spectrometry (MS) is presented. Both of these compound classes are frequently found in the indoor environment due to their use as bulk additives in numerous polymers, consumer products and building materials. GC/MS utilizing positive ion chemical ionisation (PICI) in selected reaction monitoring (SRM) mode with isobutane as the reagent gas was found to be the best of the tested methods; it proved superior to electron ionisation (EI) in selected ion monitoring (SIM) mode and to PICI using methane as the reagent gas. The method was applied to indoor air samples collected by active air sampling using solid-phase extraction (SPE) cartridges. Organophosphates and phthalates were simultaneously determined with method detection limits (MDLs) in the range of 0.1-47 ng m(-3). For most compounds the MDLs were <= 0.2 ng m(-3), but due to the presence of some of these ubiquitous indoor air pollutants in the blanks, significantly higher MDLs were observed for a few compounds. Finally, the method was also applied in the screening of a much more complex sample matrix, indoor dust.

  • 3. Björklund, Jonas
    et al.
    Isetun, Sindra
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Nilsson, Ulrika
    Selective determination of organophosphate flame-retardants and plasticizers in indoor air by gas chromatography, positive-ion chemical ionization and collision-induced dissosiation mass spectrometry2004In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 18, no 24, p. 3079-3083Article in journal (Refereed)
    Abstract [en]

    Gas chromatography/ion trap mass spectrometry with in-source ionization and dissociation was used in positive-ion chemical ionization (PICI) mode for the determination of organophosphate triesters in indoor air. These compounds are widely used as additive flame retardants and plasticizers in different types of materials and have become ubiquitous pollutants in indoor environments. When using collision-induced dissociation in PICI mode the fragmentation of the organophosphate triesters can be performed in a more controllable way than in electron ionization (EI) mode. The developed selected-reaction monitoring method provided high selectivity for the investigated compounds. For 8-h air measurements (corresponding to 1.5 m3 of sampled air) the limit of detection of the method was determined to be in the range 0.1–1.4 ng m−3, which is comparable with nitrogen-phosphorus detection and about 50-fold lower than when using EI in selected-ion monitoring mode. The presented method was applied to samples from three common indoor environments, in which a number of organophosphate triesters were identified and quantified. The dominating compound was found to be tris(2-chloropropyl) phosphate, which occurred at levels up to 0.8 μg m−3.

  • 4. Daikoku, Shusaku
    et al.
    Widmalm, Göran
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Kanie, Osamu
    Analysis of a series of isomeric oligosaccharides by energy-resolved mass spectrometry: a challenge on homobranched trisaccharides2009In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 23, no 23, p. 3713-3719Article in journal (Refereed)
  • 5.
    Fred, Charlotta
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Chemistry.
    Cantillana, Tatiana
    Henderson, Alistair
    Golding, Bernard T.
    Törnqvist, Margareta
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK), Environmental Chemistry.
    Adducts to N-terminal valines in hemoglobin from isoprene di-epoxide, a metabolite of isoprene2004In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 18, no 18, p. 2177-2184Article in journal (Refereed)
    Abstract [en]

    Isoprene (2-methylbuta-1,3-diene) is a multi-site carcinogen in rodents. To evaluate the role of the diepoxide metabolite (1,2:3,4-diepoxy-2-methylbutane) in carcinogenesis, measurements of in vivo doses of the diepoxide are needed. The in vivo dose may be inferred from levels of reaction products with hemoglobin (Hb adducts). This report presents in vitro studies of the adduct formation by the diepoxide of isoprene with valinamide and oligopeptides as model compounds of N-terminal valines in hemoglobin (Hb). In the reaction with valinamide it was shown that isoprene diepoxide forms as the main product a ring-closed adduct, which is a pyrrolidine derivative [N,N-(2,3-dihydroxy-2-methyl-1,4-butadiyl)valinamide, MPyr-Val]. The analysis was performed by gas chromatography/mass spectrometry (GC/MS) (EI and PICI) after acetylation. The ring-closed adduct was also identified by liquid chromatography/electrospray ionization mass spectrometry (LC/ESI-MS) as the main product in the reaction between isoprene diepoxide and standard hepta- or (2H8)octapeptides, corresponding to the N-terminal peptides of the α-chains in mouse and rat Hb. These peptides, alkylated with isoprene diepoxide, to be used as internal standards and calibration standards for quantification of MPyr-adduct levels in vitro and in vivo, were analyzed with respect to the degree of MPyr-alkylation by two independent methods, amino acid analysis and HPLC-UV; similar results were obtained using these methods. A method for measurement of Hb adducts as modified peptides, used earlier to measure a similar adduct to N-terminal valines in Hb from the diepoxide of 1,3-butadiene, has in the present work been tested for application to isoprene diepoxide. The method is based on tryptic degradation of globin and LC/ESI-MS analysis of N-terminal Pyr-heptapeptides of the Hb α-chain enriched by HPLC. MPyr-adduct levels in isoprene diepoxide alkylated hemolysate from mouse erythrocytes incubated with different concentrations of isoprene diepoxide (2 and 10 mM) for 1 h were quantified. The adduct level was about 50 nmol/g α-chain Hb per mM × h. From the adduct levels the rate constant of isoprene diepoxide for reaction with N-terminal valine was calculated to be about 1.6 times faster than for diepoxybutane

  • 6.
    Glykou, Aikaterini
    et al.
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Eriksson, Gunilla
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Storå, Jan
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Osteoarchaeological Research Laboratory.
    Schmitt, M.
    Kooijman, E.
    Lidén, Kerstin
    Stockholm University, Faculty of Humanities, Department of Archaeology and Classical Studies, Archaeological Research Laboratory.
    Intra- and inter-tooth variation in strontium isotope ratios from prehistoric seals by laser ablation multi-collector inductively coupled plasma mass spectrometry2018In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 32, no 15, p. 1215-1224Article in journal (Refereed)
    Abstract [en]

    RationaleStrontium isotope ratios (Sr-87/Sr-86) in modern-day marine environments are considered to be homogeneous (0.7092). However, in the Baltic Sea, the Sr ratios are controlled by mixing seawater and continental drainage from major rivers discharging into the Baltic. This pilot study explores if variations in Sr can be detected in marine mammals from archaeological sites in the Baltic Sea. Methods(87)Sr/Sr-86 ratios were measured in tooth enamel from three seal species by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The method enables micro-sampling of solid materials. This is the first time that the method has been applied to marine samples from archaeological collections. ResultsThe analyses showed inter-tooth Sr-87/Sr-86 variation suggesting that different ratios can be detected in different regions of the Baltic Sea. Furthermore, the intra-tooth variation suggests possible different geographic origin or seasonal movement of seals within different regions in the Baltic Sea through their lifetime. ConclusionsThe method was successfully applied to archaeological marine samples showing that: (1) the Sr-87/Sr-86 ratio in marine environments is not uniform, (2) Sr-87/Sr-86 differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on Sr-87/Sr-86 ratios in humans should therefore be evaluated together with diet reconstruction.

  • 7.
    Holmstrand, Henry
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Unger, Maria
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Carrizo, Daniel
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Andersson, Per
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Compound-specific bromine isotope analysis of brominated diphenyl ethers using gas chromatography multiple collector/inductively coupled plasma mass spectrometry2010In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 24, no 14, p. 2135-2142Article in journal (Refereed)
    Abstract [en]

    The bromine isotope composition is potentially diagnostic in both degradation monitoring and source apportionment of organobromines in the environment. A method for compound-specific bromine isotope analysis (delta Br-81) based on gas chromatography multiple collector inductively coupled plasma mass spectrometry (GC/ICPMS) was developed for common brominated diaromatic compounds. Brominated diphenyl ethers (BDEs) in Bromkal 70-5DE, a technical flame-retardant mixture containing mainly BDEs #47, #99 and #100, were used as test substances, with standard bracketing for the samples achieved through co-injected monobromobenzene (MBB) with a known delta Br-81 of -0.39 parts per thousand vs. Standard Mean Ocean Bromine (SMOBr). Three different heated transfer lines were constructed and tested to achieve efficient conduction of the BDEs from the gas chromatograph to the ICPMS instrument. The MBB was analyzed with a precision of 0.4 parts per thousand (1 s, n = 18). The precision for BDEs was 1.4-1.8 parts per thousand (1 s, n = 10-12 depending on the congener). The lower precision for the BDEs than for MBB may reflect the heat required to prevent condensation of the analytes in ICP torch assembly. The use of an internal standard of similar chemical structure to the analytes alleviates this problem, as illustrated by a difference of 0.3 +/- 0.7 parts per thousand (1 s, n = 6) between the (delta Br-81 values of co-injected methoxy BDE-47 and BDE-47 extracted from whale blubber. Improvements in precision and accuracy may be achieved by the use of a more efficient heating of the torch assembly in conjunction with a set of internal standards that match the target compounds.

  • 8.
    Horst, Axel
    et al.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Holmstrand, Henry
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Andersson, Per
    Andersson, August
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Carrizo, Daniel
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Thornton, Brett F.
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Gustafsson, Örjan
    Stockholm University, Faculty of Science, Department of Applied Environmental Science (ITM).
    Compound-specific bromine isotope analysis of methyl bromide using gas chromatography hyphenated with inductively coupled plasma multiple-collector mass spectrometry2011In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 25, no 17, p. 2425-2432Article in journal (Refereed)
    Abstract [en]

    Methyl bromide is the most important natural bromine contributor to stratospheric ozone depletion, yet there are still large uncertainties regarding quantification of its sources and sinks. The stable bromine isotope composition of CH(3)Br is potentially a powerful tool to apportion its sources and to study both its transport and its reactive fate. A novel compound-specific method to measure (81)Br/(79)Br isotope ratios in CH3Br using gas chromatography hyphenated with inductively coupled plasma multiple-collector mass spectrometry (GC/MCICPMS) was developed. Sample amounts of >40 ng could bemeasured with a precision of 0.1 parts per thousand (1 sigma, n=3). The method results are reproducible over the long term as shown with 36 analyses acquired over 3 months, yielding a standard deviation ( 1s) better than 0.4 parts per thousand. This new method demonstrates for the first time Br isotope ratio determination in gaseous brominated samples. It is three orders of magnitude more sensitive than previously existing isotope ratio mass spectrometry methods for Br isotope determination of other organobromines, thus allowing applications towards ambient atmospheric samples.

  • 9.
    Mashayekhy Rad, Farshid
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Leck, Caroline
    Stockholm University, Faculty of Science, Department of Meteorology .
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Nilsson, Ulrika
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Investigation of ultrahigh-performance liquid chromatography/travelling-wave ion mobility/time-of-flight mass spectrometry for fast profiling of fatty acids in the high Arctic sea surface microlayer2018In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 32, no 12, p. 942-950Article in journal (Refereed)
    Abstract [en]

    Rationale

    Fatty acids are enriched in the ocean surface microlayer (SML) and have as a consequence been detected worldwide in sea spray aerosols. In searching for a relationship between the properties of the atmospheric aerosol and its ability to form cloud condensation nuclei and to promote cloud droplet formation over remote marine areas, the role of surface active fatty acids sourced from the SML is of interest to be investigated. Here is presented a fast method for profiling of major fatty acids in SML samples collected in the high Arctic (89 °N, 1 °W) in the summer of 2001.

    Methods

    UHPLC/travelling‐wave ion mobility spectrometry (TWIMS)/time‐of‐flight (TOF) mass spectrometry (MS) for profiling was evaluated and compared with UHPLC/TOFMS. No sample preparation, except evaporation and centrifugation, was necessary to perform prior to the analysis.

    Results

    TOFMS data on accurate mass, isotopic ratios and fragmentation patterns enabled identification of the fatty acids. The TWIMS dimension added to the selectivity by extensive reduction of the noise level and the entire UHPLC/TWIMS/TOFMS method provided a fast profiling of the acids, ranging from C8 to C24. Hexadecanoic and octadecanoic acids were shown to yield the highest signals among the fatty acids detected in a high Arctic SML sample, followed by the unsaturated octadecenoic and octadecadienoic acids. The predominance of signal from even‐numbered carbon chains indicates a mainly biogenic origin of the detected fatty acids.

    Conclusions

    This study presents a fast alternative method for screening and profiling of fatty acids, which has the advantage of not requiring any complicated sample preparation thus limiting the loss of analytes. Almost no manual handling, together with the very small sample volumes needed, is certainly beneficial for the determination of trace amounts and should open up the field of applications to also include atmospheric aerosol and fog.

  • 10.
    Miska, Milena E.
    et al.
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Shouakar-Stash, Orfan
    Holmstrand, Henry
    Stockholm University, Faculty of Science, Department of Environmental Science and Analytical Chemistry.
    Stable chlorine isotope analysis of chlorinated acetic acids using gas chromatography/quadrupole mass spectrometry2015In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 29, no 24, p. 2341-2348Article in journal (Refereed)
    Abstract [en]

    RationaleThe environmental occurrence of chlorinated acetic acids (CAAs) has been extensively studied, but the sources and transport are still not yet fully understood. A promising approach for source apportionment and process studies is the isotopic characterization of target compounds. We present the first on-line stable chlorine isotope analysis of CAAs by use of gas chromatography/quadrupole mass spectrometry (GC/qMS). MethodsFollowing approved procedures for concentration analysis, CAAs extracted into MTBE were methylated to GC-amenable methyl esters (mCAAs). These mCAAs were then analyzed by GC/qMS for their stable chlorine isotope composition using a sample/standard-bracketing approach (CAA standards in the range Cl-37 -6.3 to -0.2 , Standard Mean Ocean Chloride). ResultsCross-calibration of the herein presented method with off-line reference methods (thermal ionization and continuous-flow GC isotope ratio mass spectrometry; TI-MS and CF-GC/IRMS, respectively) shows good agreement between the methods (regression slope for GC/qMS vs reference method data sets: 0.92 +/- 0.29). Sample amounts as small as 10 pmol Cl can herewith be analyzed with a precision of 0.1 to 0.4 parts per thousand. ConclusionsThis method should be useful for environmental studies of CAAs at ambient concentrations in precipitations (<0.06 to 100nmolL(-1)), surface waters (<0.2 to 5nmolL(-1)) and soil (<0.6 to 2000nmolkg(-1) dry soil) where conventional off-line methods cannot be applied.

  • 11.
    Shariatgorji, Mohammadreza
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Spacil, Zdenek
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Maddalo, Gianluca
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Cardenas, Lourdes B.
    Plant Biology Division, Institute of Biological Sciences, University of the Philippines Los Banos, College, Laguna 4031, The Philippines.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Matrix-free thin-layer chromatography/laser desorption ionization mass spectrometry for facile separation andidentification of medicinal alkaloids2009In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 23, no 23, p. 3655-3660Article in journal (Refereed)
    Abstract [en]

    Quaternary protoberberine alkaloids belong to a pharmaceutically important class of isoquinoline alkaloids associated with bactericidal, fungicidal, insecticidal and antiviral activities. As traditional medicine gains wider acceptance, quick and robust analytical methods for the screening and analysis of plants containing these compounds attract considerable interest. Thin-layer chromatography (TLC) combined with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) is a powerful technique but suffers from dilution of the TLC bands resulting in decreased sensitivity and masking of signals in the low-mass region both due to addition of matrix. This study integrates for the first time conventional silica gel TLC and laser desorption ionization mass spectrometry (LDI-MS) thus eliminating the need for any external matrix. Successful separation of berberine (Rf = 0.56) and palmatine (Rf = 0.46) from Berberis barandana including their identification by MS are demonstrated. Furthermore, a robust electrospray ionization (ESI)-MS method utilizing residual sample from TLC for quantification of berberine applying selected reaction monitoring and standard addition method is presented. The amount of berberine in the plant root prepared for the study was determined to be 0.70% (w/w). Copyright © 2009 John Wiley & Sons, Ltd.

  • 12.
    Spacil, Zdenek
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Shariatgorji, Mohammadreza
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Amini, Nahid
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Solich, Petr
    Department of Analytical Chemistry, Faculty of Pharmacy, Charles University in Prague, Heyrovskeho 1203, 500 05 Hradec Kralove, Czech Republic.
    Ilag, Leopold L.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Matrix-less laser desorption/ionisation mass spectrometry of polyphenols in red wine2009In: Rapid Communications in Mass Spectrometry, ISSN 0951-4198, E-ISSN 1097-0231, Vol. 23, no 12, p. 1834-1840Article in journal (Refereed)
    Abstract [en]

    Matrix-assisted laser desorption/ionisation (MALDI) of small molecules is challenging and in most cases impossible due to interferences from matrix ions precluding analysis of molecules <300-500 Da. A common matrix such as ferulic acid belongs to an important class of compounds associated with antioxidant activity. If the shared phenolic structure is related to the propensity as an active MALDI matrix then it follows that direct laser desorption/ionisation should be possible for polyphenols. Indeed matrix-less laser desorption/ionisation mass spectrometry is achieved whereby the analyte functions as a matrix and was used to monitor low molecular weight compounds in wine samples. Sensitivity ranging from 0.12-87 pmol/spot was achieved for eight phenolic acids (4-coumaric, 4-hydroxybenzoic, caffeic, ferulic, gallic, protocatechuic, syringic, vanillic) and 0.02 pmol/spot for trans-resveratrol. Additionally, 4-coumaric, 4-hydroxybenzoic, caffeic, ferulic, gallic, syringic, vanillic acids and trans-resveratrol were identified in wine samples using accurate mass measurements consistent with reported profiles based on liquid chromatography (LC)/MS. Minimal sample pre-treatment make the technique potentially appropriate for fingerprinting, screening and quality control of wine samples. Copyright © 2009 John Wiley & Sons, Ltd.

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