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  • 1.
    Gustavsson, Marcus
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Meiby, Elinor
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Gylestam, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dahlin, Jakob
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Spanne, Mårten
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Tveterås, Björn Oscar
    Pedersen, Age Engen
    Adsorption Efficiency of Respirator Filter Cartridges for Isocyanates2010In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 54, no 4, p. 377-390Article in journal (Refereed)
    Abstract [en]

    In some industries, the temperature and the humidity will vary greatly between different work places, such as outdoor work in arctic or tropical climates. There is therefore a need to test respirator filters at conditions that simulate conditions that are relevant for the industries that they are used in. Filter cartridges were exposed to controlled atmospheres of varying isocyanate concentration, air humidity, and temperature in an exposure chamber. For isocyanic acid (ICA) and methyl isocyanate (MIC), the exposure concentrations were between 100 and 200 p.p.b., monitored using a proton transfer reaction mass spectrometer. ICA and MIC were generated by continuous thermal degradation of urea and dimethylurea. The breakthrough was studied by collecting air samples at the outlet of the filter cartridges using impinger flasks or dry samplers with di-n-butylamine as derivatization reagent for isocyanates followed by liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. For hexamethylene diisocyanate (HDI) and isophorone diisocyanate (IPDI), the exposure concentrations were between 4 and 20 p.p.b. and were generated by wet membrane permeation. To reveal the profile of adsorption in different layers of the respirator filters, representative samples from each of the layers were hydrolyzed. The hydrolysis products hexamethylene diamine and isophorone diamine were determined after derivatization with pentafluoropropionic anhydride (PFPA) followed by LC-MS/MS analysis. The two filter types studied efficiently absorbed both ICA and MIC. There was no trend of impaired performance throughout 48-h exposure tests. Even when the filters were exposed to high concentrations (similar to 200 p.p.b.) of ICA and MIC for 96 h, the isocyanates were efficiently absorbed with only a limited breakthrough. The majority of the HDI and IPDI (> 90%) were absorbed in the top layers of the absorbant, but HDI and IPDI penetrated farther down into the respirator filters during 120 h of exposure as compared to 16 h exposure.

  • 2.
    Gylestam, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Gustavsson, Marcus
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry. Institutet för Kemisk Analys Norden AB, Sweden.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry. Institutet för Kemisk Analys Norden AB, Sweden.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Sampling of Respirable Isocyanate Particles2014In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 58, no 3, p. 340-354Article in journal (Refereed)
    Abstract [en]

    An advanced design of a denuder impactor (DI) sampler has been developed for characterization of possible airborne isocyanate exposure in different particle size fractions. The sampler is equipped with 12 different parallel denuder tubes, 4 impaction stages with the cut-off values (d50) of: 9.5, 4, 2.5 and 1 µm, and an end filter that collects particles < 1 µm. All collecting parts were impregnated with di-n-butylamine DBA as the reagent in a mixture with acetic acid. The performance of the DI sampler was studied on a standard atmosphere containing gas and particulate isocyanates. The isocyanate atmosphere was generated by liquid permeation of 2,4-, 2,6-Toluene Diisocyanate (TDI), 1,6-Hexamethylene Diisocyanate (HDI) and Isophorone Diisocyanate (IPDI). 4,4’-Methylene Diphenyl Diisocyanate (MDI) particles were generated by heating of technical MDI and condensing the mixture of gas and particle-borne MDI in an atmosphere containing mixed salt particles. The study was performed in a 0.85 m3 environmental chamber with stainless steel walls. With the advancement of the DI sampler it is now possible to collect isocyanate particle samples for up to 320min. The performance of the DI sampler is essentially unaffected by the humidity. The DI sampler and the ASSET™ EZ4-NCO sampler (Sigma-Aldrich/Supelco, Bellefonte, PA, USA) gave similar results. Sample losses within the DI sampler are low. In the environmental chamber it was observed that the particle distribution may be affected by the humidity and ageing. A scanning mobility particle sizer (SMPS) was used to separate a flow of selected fractions containing MDI particles from mixed MDI and salt particles. The particle-size distribution had a maximum at about 300nm, but later in the environmental chamber 1 µm dominated. The distribution was very different as compared to with only NaCl or MDI present. The biological relevance for studying isocyanate nano particles is significant as these have the possibility to reach the lower airways where allergic reactions may occur. SMPS and isocyanate air sampling can be used for the investigation of isocyanate nano particles.

  • 3.
    Gylestam, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of Gas Phase Isocyanates Using Proton Transfer Reaction Mass Spectrometry2011In: Analytical Chemistry Letters, ISSN 2229-7928, Vol. 1, no 4, p. 261-271Article in journal (Refereed)
    Abstract [en]

    We report the development of proton transfer reaction-mass spectrometry (PTR-MS) methodology for on-line monitoring, using a direct reading instrument, of several typical gas phase isocyanates, including isocyanic acid (ICA), ethyl isocyanate (EIC), phenyl isocyanate (PhI), hexamethylene diisocyanate (HDI) and toluene diisocyanate (TDI). In the study, ICA and MIC were generated by thermal degradation of urea and 1,3-dimethylurea, respectively, while the other isocyanates were generated by liquid and gas permeation techniques. Comparative, reference measurements were made by sampling isocyanate atmosphere using impinger flasks containing the reagent di-n-butyl amine (DBA) then determining the resulting DBA derivatives by liquid chromatography (LC)-MS/MS. Reproducible measurements were obtained, with a <10 % drift in PTR-MS responses during a 12 month period. Further, there were linear correlations (R2>0.99) between the data acquired by the PTR-MS technique and air sampling followed by LC-MS/MS for all tested isocyanates in the concentration range 2-100 ppb, with a PTR-MS detection limits in the low ppb range. For all isocyanates except EIC, BIC, HDI and IPDI, the protonated molecular ions were the most abundant ions in the PTR mass spectra. Overall, the results show that the developed method enables sensitive, time-resolved measurements of airborne isocyanates to be acquired over several weeks.

  • 4.
    Gylestam, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Riddar, Jakob B.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dahlin, Jakob
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dry Sampling of Gas-Phase Isocyanates and Isocyanate Aerosols from Thermal Degradation of Polyurethane2014In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162, Vol. 58, no 1, p. 28-49Article in journal (Refereed)
    Abstract [en]

    The performance of a dry sampler, with an impregnated denuder in series with a glass fibre filter, using di-n-butylamine (DBA) for airborne isocyanates (200ml min−1) is investigated and compared with an impinger flask with a glass fibre filter in series (1 l min−1). An exposure chamber containing 1,6-hexamethylene diisocyanate (HDI), isophorone diisocyanate (IPDI), and 2,4- and 2,6-toluene diisocyanate (TDI) in the concentration range of 5–205 μg m−3 [0.7–33 p.p.b.; relative humidity (RH) 50%], generated by gas- and liquid-phase permeation, was used for the investigation. The precision for the dry sampling for five series with eight samplers were in the range of 2.0–6.1% with an average of 3.8%. During 120-min sampling (n = 4), no breakthrough was observed when analysing samplers in series. Sixty-four exposed samplers were analysed after storage for 0, 7, 14, and 21 days. No breakdown of isocyanate derivatives was observed. Twenty-eight samplers in groups of eight were collecting isocyanates during 0.5–32h. Virtually linear relationships were obtained with regard to sampling time and collected isocyanates with correlation coefficients in the range of 0.998–0.999 with the intercept close to the origin. Pre- or post-exposure to ambient air did not affect the result. Dry sampling (n = 48) with impinger-filter sampling (n = 48) of thermal decomposition product of polyurethane polymers, at RH 20, 40, 60, and 90%, was compared for 11 isocyanate compounds. The ratio between the different isocyanates collected with dry samplers and impinger-filter samplers was in the range of 0.80–1.14 for RH = 20%, 0.8–1.25 for RH = 40%, 0.76–1.4 for RH = 60%, and 0.72–3.7 for RH = 90%. Taking into account experimental errors, it seems clear that isocyanic acid DBA derivatives are found at higher levels in the dry samples compared with impinger-filter samplers at elevated humidity. The dry sampling using DBA as the reagent enables easy and robust sampling without the need of field extraction.

  • 5.
    Karlsson, Daniel
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of Cotinine in Urine and Saliva Using Hydrophilic Interaction Liquid Chromatography and Tandem Mass Spectrometry2011In: Analytical Chemistry Letters, ISSN 2229-7928, Vol. 1, no 1, p. 25-33Article in journal (Refereed)
    Abstract [en]

    A new simplified method for monitoring of cotinine in urine and saliva, based on hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS) is presented. Work-up techniques based on filtration, using 0.45 μm pore sizepolypropylene filter, of crude urine and saliva and alkaline extraction of cotinine with methylene dichloride were studied. Multiple reaction monitoring (MRM) of the protonated molecular ions of cotinine and tri-deuterium labelled cotinine resulted in selective determinations with linear calibration graphs (correlation coefficients >0.999) The precision for 10 samples, containing 100 ng cotinine /ml, prepared from urine and saliva by methylene dichloride extraction or filtration were between 2 and 5 %. The detection limit for extracted and filtrated saliva was 2 fmol and for extracted and filtrated urine it was 5 and 9 fmol, respectively. Agreement was obtained for the two different work-up techniques. Extraction of urine/saliva enabled detection at lower levels (down to 5 pg cotinine/ml of urine) compared to filtration, since the possibility of enrichment of the sample but also due to reduction of interfering compounds present in the matrix. However, when performing large exposure studies with many samples to be analysed, the simplified and time saving work-up procedure obtained with filtration is valuable.

    The higher organic content of the effluent in the HILIC mode and a more efficient separation of polar compounds present in the matrix, favoured the electrospray ionisation compared to reversed phase (RP) LC, thus enabling lower detection limits.

  • 6.
    Marand, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dahlin, Jakob
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Determination of technical grade isocyanates used in the production of polyurethane plastics2004In: Journal of Environmental Monitoring, Vol. 6, no 7, p. 606-614Article in journal (Refereed)
    Abstract [en]

    A method for determination of technical grade isocyanates used in the production of polyurethane (PUR) is presented. The isocyanates in technical grade products were characterised as di-n-butylamine (DBA) derivatives using LC-MS and LC-chemiluminescent nitrogen detection (CLND) and the total isocyanate content was compared to a titration assay. For collection of isocyanates in air, an impinger–filter sampling technique with DBA as derivatisation reagent was used. Characterised DBA and nonadeuterium labelled DBA derivatives of isocyanates in technical products were used as calibration standards and internal standards, respectively, in the analysis of air samples. Three workplaces were studied where PUR products were produced either by spraying or by moulding. In both technical products and in air samples, a number of monomeric, oligomeric and prepolymeric isocyanates of e.g. methylenebisphenyl diisocyanate (MDI) and hexamethylene diisocyanate (HDI) were characterised. Several of these have not previously been described in workplace atmospheres. In the technical isocyanate products, between 69 and 102% of the NCO content determined by titration was accounted for by LC-CLND. Quantifications of a wide range of isocyanates in air samples were performed with correlation coefficients in the range 0.988–0.999 (n= 8) and the instrumental detection limits were 0.7–25 pg. At the two workplaces where MDI- and HDI isocyanurate-based products were sprayed, the isocyanate composition in the air reflected the composition in the technical product. At the workplace where a MDI-based product was used in a moulding process, only the monomeric isocyanates were found in the air. The advantage of using characterised technical grade isocyanates as analytical standards was clearly demonstrated and the possibility of using index compounds when monitoring isocyanate exposure is discussed.

  • 7.
    Marand, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of amines as pentafluoropropionic acid anhydride derivatives in biological samples using liquid chromatography and tandem mass spectrometry2004In: The Analyst, ISSN 0003-2654, Vol. 129, no 6, p. 522-528Article in journal (Refereed)
    Abstract [en]

    Determination of amines in biological samples as markers of exposure to the amines or the corresponding isocyanates is an important tool for industrial exposure assessment. In this study, a liquid chromatography and tandem mass spectrometry (LC- MS/ MS) method for determination of amines in biological samples as perfluorofatty amides derivatives is presented. The method enables determination of diamines such as methylene diamine (MDA), toluene diamine (TDA), naphthalene diamine (NDA), hexamethylene diamine (HDA), isophorone diamine (IPDA), methylenedi( cyclohexylamine) (HMDA) and 4,4'-methylene-(2-chloroaniline) (MOCA) in human urine and plasma. The work-up procedure included hydrolysis of the biological samples with 3 M H2SO4 at 100degreesC for 16 h and extraction of the amines into toluene, where derivatisation of the amines with perfluorofatty acid anhydride was performed. Following removal of excess reagent and the acid formed and an exchange of solvent, the derivatives were analysed using gradient elution with an acetonitrile/water mobile phase composition and electrospray ionisation (ESI) with multiple reaction monitoring (MRM) of [M - H](-) --> [M - H - 120](-) or [119](-). Several perfluorofatty acid anhydrides were evaluated as derivatisation reagents, but the LC chromatographic properties of the pentafluoropropionic acid anhydride (PFPA) derivatives were favourable. Quantification of amine - PFPA derivatives was performed using deuterium labelled amine - PFPA derivatives as internals standards with good precision and linearity in the investigated range of 0 - 20 ng ml(-1) urine. The instrumental detection limits for the amine - PFPA derivatives were 0.2 - 3 fmol for MRM of [M - H](-) --> [119](-) and 0.3 - 8 fmol for [M - H](-) --> [M - H - 120](-). In 10 urine and 6 plasma samples from workers exposed to isocyanates, determination of TDA and MDA as PFPA derivatives was performed using LC- MS/ MS and a reference GC-MS method. No significant difference between the two methods was observed.

  • 8.
    Marand, Åsa
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Extractable organic compounds in polyurethane foam with special reference to aromatic amines and derivatives thereof2004In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 510, no 1, p. 109-119Article in journal (Refereed)
    Abstract [en]

    Methods for determination of aromatic amines and related compounds in flexible toluene diisocyanate (TDI)-based polyurethane (PUR) foam were investigated. The foam was extracted using 0.1% (w/v) aqueous acetic acid (HAc). Extraction solutions were analysed and aromatic amines were determined as ethyl chloroformate (Et) and pentafluoropropionic acid anhydride (PFPA) derivatives. The determinations were performed using liquid chromatography (LC) and mass spectrometry (MS) detection with electrospray ionisation (ESI) or gas chromatography (GC)-MS with chemical ionisation monitoring negative ions (NCI). The Et derivatives were determined using LC-ESI+-MS with detection limit of 2 pg of toluenediamine (TDA). The PFPA derivatives were determined using LC-ESI--MS or GC-NCI-MS with detection limits of 0.1 and 0.02 pg of TDA, respectively. Using trideuterium labelled TDA as internal standard, linear calibration curves were obtained in the range of 0.01-0.50 mug ml(-1) (n = 7), with correlation coefficients >0.999. When plotting calibration curves for TDA-PFPA derivatives determined using LC-MS against TDA-PFPA using GC-MS and TDA-Et using LC-MS, linear curves were obtained. The relative standard deviation (R.S.D.) for determination of TDA in foam extraction solutions were 13%. LC-MS determination of PFPA derivatives was more selective, as compared to LC-MS of Et derivatives.

    In foam extraction solutions, 2,4- and 2,6-TDA, several isomers of methylenedianiline (MDA) and dimers of TDA/TDI were observed. 2,4-TDA and 4,4'-MDA are possible human carcinogens. Hydrolysis of the extraction solution revealed a large pool of TDA/TDI compounds and oligomers. The concentration of TDA in foam was affected by the extraction media, temperature and duration. The choice of derivatisation procedure also affected the determination of TDA. In extraction solutions from six different commercially available flexible foam qualities 2,4- and 2,6-TDA were found in the range of 0-7 and 0-6 mug g(-1) foam, respectively. When flexible foam was heated, considerable higher concentrations of TDA were observed.

  • 9.
    Riddar, Jakob B.
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    A novel sampler for aliphatic amines and a new method for determination using hydrophilic interaction liquid chromatography tandem mass spectrometryManuscript (preprint) (Other academic)
    Abstract [en]

    A novel sampler for determination of airborne aliphatic amines is presented using hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry (MSMS). The sampler consisted of a denuder comprising a polypropylene tube (length = 7 cm, ID = 0.8 cm) with an inner wall coated with a glass fibre filter and internal glass fibre filter strip folded into a ‘V’ to increase the denuder surface coupled in series with a 13 mm glass fibre filter. Sulphuric acid was used for impregnation of all the filters.

    Electrospray ionisation and multiple-reaction monitoring (MRM) of the protonated molecular ions and corresponding deuterium-labelled internal standards resulted in selective determination with linear correlation coefficients > 0.995,  instrumental precision (n = 16) < 6 %  and detection limits of 1.9 - 150 pg (2.6 - 195 ng mL-1) for ethylamine (EA), allylamine (AA), isopropanol amine (IPA), n-butylamine (NBA), diethylamine (DEA), dimethylethylamine (DMEA), cyclohexylamine (CHA), diisopropylamine (DIPA) and triethylamine (TEA).

    The performance of the sampler was investigated by sampling a standard atmosphere of AA, IPA, NBA, DEA, DMEA, CHA and TEA (0.5-15.4 mg m-3) in an exposure chamber (0.3 m3). The air concentrations of the amines were generated by gas phase membrane permeation.

    The extraction recovery for spiked samplers (10-100 μg) was in the range 93-106 % (except for DMEA 127 %). The precision when sampling three series of ten samplers each was in the range 1.8-7.0 %. Collection efficiencies of > 99.9 % without breakthrough were observed for the studied amines when sampling over 60 min using four sets of two samplers in sequence at a flow rate of 200 mL min-1. Major breakthrough was observed for TEA and DMEA at 800 mL min-1 with collection efficiencies > 82 %. For CHA, DEA, NBA, IPA and AA, the collection efficiencies were > 97 %. The distribution of the aliphatic amines in the sampler was studied by dissection of the denuders (into eight parts) for two different flow rates (200 and 1100 mL min-1). The first parts of the denuder collected the highest amount of aliphatic amines, which then declined throughout the remaining parts. Thus, it was deemed that the denuder was too short to collect all gas phase amines and the presence of the end filter was necessary for efficient collection. No effect was observed on the collection efficiency when samplers were stored for up to 45 days prior to sampling. No degradation of the amines on the sampler was observed when exposed samplers were stored for up to 45 days. When sampling IPA, DEA and TEA over a period of 0.5 - 8 h (n = 6), linear relationships were obtained with correlation coefficients > 0.997. Using sampling flow rates of 50-800 mL min−1, linear relationships were obtained with correlation coefficients > 0.977. Pre- or post-exposure to ambient air for up to 10 h at 25 °C or 50 °C did not affect the sampler performance.

  • 10.
    Riddar, Jakob B.
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    A novel sampler for alkanolamines and a new method for determination using hydrophilic interaction liquid chromatography tandem mass spectrometry2014In: Annals of Occupational Hygiene, ISSN 0003-4878, E-ISSN 1475-3162Article in journal (Refereed)
    Abstract [en]

    A novel sampler for determination of airborne alkanolamines is presented using hydrophilic interaction liquid chromatography (HILIC) with tandem mass spectrometry (MSMS). The sampler consisted of a denuder comprising a polypropylene tube (length = 7 cm, ID = 0.8 cm) with an inner wall coated with a glass fibre filter and internal glass fibre filter strip folded into a ‘V’ to increase the denuder surface coupled in series with a 13 mm glass fibre filter. Sulphuric acid was used for impregnation of all the filters.

    Electrospray ionisation and multiple-reaction monitoring (MRM) of the protonated molecular ions and corresponding deuterium-labelled internal standards resulted in selective quantifications with linear correlation coefficients > 0.992,  instrumental precision (n = 16) of < 6 %  and detection limits of 5.1 – 48 pg for ethanol amine (EA), n-propanol amine (NPA), isopropanol amine (IPA), dimethylethanol amine (DMEA), diethanol amine (DEA), diethylethanol amine (DEEA), methyldiethanol amine (MDEA), diisopropanol amine (DIPA) and triethanolamine (TEA).

    The performance of the sampler was investigated by sampling a standard atmosphere of EA, IPA, DMEA, DEEA and MDEA (0.03-6.1 mg m-3) in an exposure chamber (0.3 m3). The air concentrations of the amines were generated by liquid phase membrane permeation.

    The extraction recovery for spiked samplers (10 μg) was in the range 93-106 %. The precision when sampling three series of ten samplers each was in the range 2.1-4.8 %. No breakthrough was observed from the sampler when sampling during 60 min using four sets of two samplers in sequence at a flow rate of 0.2 L min-1. A minor breakthrough was observed for DEEA and DMEA at 0.8 L min-1 and the collection efficiencies were > 99.4 %. The distribution of the alkanolamines in the sampler was studied by dissection of the denuders (into eight parts) for two different flow rates (0.2 and 1.1 L min-1). The first parts of the denuder collected the highest amount of alkanolamines, which then declined throughout the remaining parts. It was observed that the denuder was too short to collect all the gas phase alkanolamines and the presence of the end filter was necessary for efficient collection. No effect was observed on the collection efficiency when samplers were stored for up to 45 days prior sampling. No degradation of the alkanolamines on the sampler was observed when exposed samplers were stored for up to 45 days. When sampling DMEA and DEEA, over a period of 0.5 - 8 h (n = 6), linear relationships were obtained with correlation coefficients > 0.998. Using sampling flow rates of 0.05 - 0.8 L min−1, linear relationships were obtained with correlation coefficients > 0.974. Pre- or post-exposure to ambient air for up to 10 h at 25 °C or 50 °C did not affect the sampler performance.

  • 11.
    Riddar, Jakob B.
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Analysis of Aqueous Alkanolamines using Hydrophilic Interaction Liquid Chromatography and Mass Spectrometr2013In: Analytical Chemistry Letters, ISSN 2229-7928, Vol. 3, no 5-6, p. 298-313Article in journal (Refereed)
    Abstract [en]

    A method for determination of mono-, di-, triethanolamine (EA, DEA, TEA), iso-, N-propanolamine (IPA, NPA),  diisopropyl ethanol amine (DIPEA), 2-diethylethanol amine (DEEA), diisopropanol amine (DIPA), dimethylethanol amine (DMEA), N-methyldiethanol amine (MDEA) in aqueous solutions is presented. Separation was achieved by zwitterionic hydrophilic interaction liquid chromatography (ZIC-HILIC). Injections of aqueous solutions were enabled by on-column focusing with partially filled loop injections. The ZIC-HILIC was coupled with a tandem mass spectrometer (MS/MS) with electrospray ionisation monitoring of positive ions. Linear calibration graphs (0.04-3.0 μg mL-1, n = 9) were obtained with correlation coefficients in the range of >0.96 using N-tripropyl amine (NTPN) as internal standard and >0.99 using NPA as internal standard. The instrumental detection limit was below 44 fmol.

    Chromatographic separation of the 10 studied alkanolamines was achieved. The most suitable composition of the focusing liquid was determined to be 1:1 AcCN/AcO, enabling injection volumes up to 3 µL whilst maintaining the chromatographic characteristics. The optimal solvent composition was found to be 100 % water with 0.01 % acid at pH < 4. Sample solution concentrations of 1.0 µg mL-1 could be injected on the column with sustained chromatography.

    To maintain stable chromatography the column needed to be regenerated after approximately 500 injections. A minimum of 5 minutes equilibration time between runs was required. The importance of equilibration was also observed after regeneration of the column to obtain chromatographic stability (peak shape and retention times), especially for the compounds eluting close to the front.

    Characterisation of the MS fragmentation pattern for the alkanolamines by hydrogen-deuterium exchange indicated a main loss of one or more water molecules. For secondary and tertiary alkanolamines the loss of an alkyl-group and/or alkanol-group was also seen.

    The possibility of using the method for determining alkanolamines in metal working fluids and in air samples was demonstrated.

  • 12.
    Riddar, Jakob Johnson
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Karlsson, Daniel
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, Marianne
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Skarping, Gunnar
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Determination of aromatic amines in aqueous extracts of polyurethane foam using hydrophilic interaction liquid chromatography and mass spectrometry2010In: Analytica Chimica Acta, ISSN 0003-2670, E-ISSN 1873-4324, Vol. 678, no 1, p. 117-123Article in journal (Refereed)
    Abstract [en]

    A method is presented for the determination of aromatic amines in aqueous extracts of polyurethane (PUR) foam. The method is based on the extraction of PUR foam using aqueous acetic acid (0.1%, w/v) followed by determination of extracted aromatic amines using hydrophilic interaction liquid chromatography (HILIC) and tandem mass spectrometry (MS/MS) with positive electrospray ionisation. The injections of volumes up to 5 mu L of aqueous solutions were made possible by on-column focusing with partially filled loop injections. The fragmentation patterns for 2,4- and 2,6-toluene diamine (TDA) and 4,4'-methylene dianiline (MDA) were clarified by performing a hydrogen-deuterium exchange study. TDA and MDA were determined using trideuterated 2,4- and 2,6-TDA and dideuterated 4,4'-MDA as internal standards. Linear calibration graphs were obtained over the range 0.025-0.5 mu g mL(-1) with correlation coefficients >0.996 and the instrumental detection limit for each compound was <50 fmol. The stability of the amines was influenced by the matrix, so their concentrations decreased over time. Agreement was observed between the results of analyses of PUR foam extracts by HILIC-MS/MS and results obtained by ethyl chloroformate derivatisation and reversed phase (RP) liquid chromatography-mass spectrometry (LC-MS/MS). TDA was observed to be unstable in extracts of foam but not in pure solutions.

  • 13.
    Skarping, G
    et al.
    Stockholm University, Faculty of Science, Department of Analytical Chemistry.
    Dalene, M
    Workplace air — Guidelines for selecting analytical methods for sampling and analysing isocyanates in air: TECHNICAL REPORT ISO/TR 17737, First edition 2007-04-012007Report (Other academic)
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