| 1. |
- Axmon, Anna, et al.
(författare)
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CYP1A1 and GSTM1 polymorphisms affect urinary 1-hydroxypyrene levels after PAH exposure
- 2000
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Ingår i: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 21:4, s. 669-676
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Tidskriftsartikel (refereegranskat)abstract
- Certain human biotransformation enzymes have been implicated in the formation and scavenging of the ultimate reactive metabolites, the diolepoxides, from polycyclic aromatic hydrocarbons (PAHs). In the present study, performed on aluminum smelter workers, we have analyzed airborne PAH, the pyrene metabolite 1-hydroxypyrene (1-OHP) in urine, and genotypes for biotransformation enzymes involved in PAH metabolism. The aim was to evaluate the correlation between external exposure and biomarkers of exposure and to investigate to what extent genetic polymorphism in metabolic enzymes can explain interindividual variation in urinary 1-OHP levels. DNA was prepared from blood samples from 98 potroom workers and 55 controls and altogether eight polymorphisms in the CYP1A1, mEH, GSTM1, GSTP1 and GSTT1 genes were analyzed. The 1-OHP excretion was found to correlate significantly (P 100-fold) and univariate and multivariate regression analyses were used to find the variables that could determine differences in excretion. The variation could, to some degree, be explained by differences in exposure to airborne particulate-associated PAHs, the use of personal respiratory protection devices, smoking habits and genetic polymorphisms in the cytochrome P450 1A1, GSTM1 and GSTT1 enzymes. The part of the variance that could be explained by differences in biotransformation genotypes seemed to be of the same order of magnitude as the variance explained by differences in exposure. In the control group as well as in the occupationally exposed group, the highest 1-OHP levels were observed in individuals carrying the CYP1A1 Ile/Val genotype who were also of the GSTM1 null genotype. The results show that urinary 1-OHP is a sensitive indicator of recent human exposure to PAHs and that it may also to some extent reflect the interindividual variation in susceptibility to PAHs.
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| 2. |
- Claeson, Anna-Sara, 1974-, et al.
(författare)
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Volatile metabolites from microorganisms grown on humid building materials and synthetic media
- 2002
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 667-672
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Tidskriftsartikel (refereegranskat)abstract
- Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.
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| 3. |
- Ekman, Jenny, et al.
(författare)
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Comparison of sampling methods for 1,6-hexamethylene diisocyanate, (HDI) in a commercial spray box
- 2002
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 127:1, s. 169-173
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Tidskriftsartikel (refereegranskat)abstract
- In this study three different types of samplers for the determination of 1,6-hexamethylene diisocyanate in air were compared. The experimental set up was a simulation of real life conditions with spray painting operations performed inside a commercial, full sized, spray box. The sampling methods were 1-(2-methoxyphenyl)-piperazine impregnated on glass fibre filter, and the same reagent in impinger, and also dibutylamine in impinger. All analyses were performed by LC-MS-MS. The determined concentrations varied between 20 and 90 microg m(-3) with relative standard deviations from 7 to 17% for each method. No significant difference was found between the three methods using ANOVA with a significance level of alpha = 0.05.
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| 4. |
- Eriksson, Kåre, et al.
(författare)
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Dermal exposure to terpenic resin acids in Swedish carpentry workshops and sawmills
- 2004
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Ingår i: Annals of Occupational Hygiene. - : Oxford University Press. - 0003-4878 .- 1475-3162. ; 48:3, s. 267-275
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: The aim of this study was to evaluate dermal exposure to the resin acids abietic acid, dehydroabietic acid and 7-oxodehydroabietic acid during collecting in sawmills and during sawing in carpentry workshops, respectively. METHODS: Sampling was performed by fastening patches at 12 different areas on a sampling overall, one patch on the front of a cap, one patch on the chest inside the clothing and one patch on the inner lower right leg. Exposure of the hands was assessed by fastening patches on cotton gloves representing the dorsal sides and the palms of the left and right hands. Sampling was performed on 30 different occasions in the sawmills and in the carpentry workshops with mean sampling times of 120 and 59 min, respectively. The acids were solvent desorbed from the patches. Identification and quantification of the resin acids was performed by gas chromatography-mass spectrometry. RESULTS: The geometric means (GMs) of the potential body exposures to abietic acid, dehydroabietic acid and 7-oxodehydroabietic acid during sawing and collecting of wood from pine and spruce were 3346 and 17 247 micro g/h, respectively. The GM of the potential exposure on the hands was 3020 micro g/h in the carpentry workshops and 4365 micro g/h in the sawmills. Resin acids were detected on the inner chest and inner lower front right leg, respectively. CONCLUSIONS: There is a potential dermal exposure to terpenic resin acids in carpentry workshops as well as in sawmills. The hands have the highest exposure during sawing as well as during collecting. There is a spatial distribution of contaminants, with the outer chest, arms and legs showing the highest exposures. Resin acids also contaminated the inner chest and inner lower leg. It is necessary to take action to reduce dermal exposure to these allergenic substances.
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| 5. |
- Eriksson, Kåre, et al.
(författare)
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Quantification of melatonin in human saliva by liquid chromatography-tandem mass spectrometry using stable isotope dilution
- 2003
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Ingår i: Journal of chromatography. B. - : Elsevier. - 1570-0232 .- 1873-376X. ; 794:1, s. 115-123
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Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of melatonin in human saliva has been developed using high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS). Saliva was collected in plastic tubes. 7-D-Melatonin was added as internal standard and the samples were cleaned and concentrated by solid-phase extraction. The limit of detection was 1.05 pg x ml(-1) and the limit of quantification was 3.0 pg x ml(-1). The accuracy of the method was +/-14% at 5.60 pg x ml(-1) and +/-9% at 19.6 pg x ml(-1). The precision was +/-13% at 6.18 pg x ml(-1) and +/-11% at 31.2 pg x ml(-1), respectively. Our HPLC-MS-MS method shows a high sensitivity and specificity for melatonin and more reliable results compared with a radioimmunoassay. The chromatographic method has been used to determine the circadian rhythm of melatonin among three nurses working the night shift and a patient suffering from an inability to fall asleep at night.
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| 6. |
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| 7. |
- Hagenbjörk-Gustafsson, Annika, et al.
(författare)
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Validation of the Willems badge diffusive sampler for nitrogen dioxide determinations in occupational environments
- 2002
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 127:1, s. 163-168
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Tidskriftsartikel (refereegranskat)abstract
- The Willems badge, a diffusive sampler for nitrogen dioxide, has previously been validated for ambient air measurements. This paper describes the laboratory and field validation of the Willems badge for personal sampling under working environment conditions. The mean sampling rate in the laboratory tests was 46 ml min(-1), with an RSD of 12%. No statistically significant effects on sampling rate of the sampling time, concentration of NO2 or relative humidity were found. A slightly decreased sampling rate was observed at low wind velocity. This was also confirmed during static sampling, which makes the sampler less appropriate for static sampling indoors. No back diffusion was observed. Storage of the samplers for two weeks before or after exposure did not affect the sampling rate. Our analysis is based on a modified colorimetric method, performed by FIA (flow injection analysis). This technique was compared to ion chromatography analysis. The use of ion chromatography lowered the detection limit from 11 to 2 microg m(-3) for an 8 h sample, and furthermore enabled the detection of other anions. In conclusion, the diffusive sampler was found to perform well for personal measurements in industrial environments.
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| 8. |
- Liljelind, Ingrid E, et al.
(författare)
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Comparison of self-assessment and expert assessment of occupational exposure to chemicals
- 2001
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Tyoterveyslaitos, Finnish Institute of Occupational Health. - 0355-3140 .- 1795-990X. ; 27:5, s. 311-317
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Occupational assessments of chemical exposure are often inadequate because of difficulties in obtaining sufficient numbers of measurements by trained professionals (experts). The objective of this study was to determine whether workers can provide unbiased data via self-assessments of exposure facilitated by the use of simple passive monitors for personal sampling.METHODS: Untrained workers obtained personal measurements of their exposures to gaseous contaminants (terpenes in sawmills and styrene in reinforced plastics factories) with passive monitors and written instructions. To study the validity of the self-assessments, an occupational hygienist performed exposure measurements on the same occupational groups after the workers had obtained two or more measurements independently. The potential bias of the self-assessments was evaluated by comparing the self-assessments with the expert assessments in mixed-effects statistical models.RESULTS: A total of 153 terpene (97 self and 56 expert) and 216 styrene (159 self and 57 expert) measurements were obtained from four sawmills and six reinforced plastics factories, respectively. No significant differences in the geometric mean exposures were observed between the self-assessments and the expert assessments in 3 of 4 sawmills and 5 of 6 reinforced plastics factories (P > 0.10). The potential bias of the self-assessments of exposure ranged from less than 0.1% to 102% and was less than 17% in 9 of the 10 groups investigated.CONCLUSIONS: The results indicate that untrained, unsupervised workers are able to collect consistently unbiased exposure data by employing currently available passive monitors.
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| 9. |
- Lindahl, R, et al.
(författare)
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Determination of morpholine in air by derivatisation with 1-naphthylisothiocyanate and HPLC analysis
- 2001
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 126:2, s. 152-154
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Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of morpholine in air was developed. Samples were collected with adsorbent tubes containing XAD-2 resin coated with 1-naphthylisothiocyanate (NIT). The thiourea derivative formed was subsequently desorbed with acetonitrile and analysed by HPLC with UV detection. The recovery after gas phase spiking with morpholine (2.2-1570 micrograms) was 91% (86-100%) with a relative standard deviation of 5.5%. No effect on recovery from relative humidity or amount of morpholine was seen. The lowest level tested corresponded to 7 mg m-3 (1/10 threshold limit value) for a 15 min sampling period with a sampling rate of 20 ml min-1. Exposed NIT-coated XAD-2 tubes were stable at room temperature for at least 2 weeks.
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| 10. |
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| 11. |
- Modig, Lars, et al.
(författare)
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Cancerframkallande ämnen i tätortsluft : Exponering och halter i Umeå 2001
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Exponeringen för ett antal cancerframkallande ämnen undersöktes i ett slumpmässigt urval av allmänbefolkningen i Umeå, 2001. Den huvudsakliga studien genomfördes från slutet av september till mitten av oktober som personburna 7-dygns mätningar på totalt 60 personer, medan några av mätningarna genomfördes i januari 2002. Parallellt med de personburna mätningarna genomfördes även mätningar vid två stationära platser i Umeå, bibliotekstaket och E4:an. Mätningarna omfattade bensen, 1,3-butadien, formaldehyd, acetaldehyd, PAH (polyaromatiska kolväten) samt kvävedioxid (NO2). Mätningarna genomfördes med passiva provtagare med undantag för PAH där provtagningen genomfördes med hjälp av en pump. Resultatet från de personburna provtagningarna av bensen gav medianvärdet 1,5 μg/m3, vilket kan jämföras med resultatet från fjolårets studie i Göteborg (1μg/m3) och den av Institutet för miljömedicin (IMM) föreslagna lågrisknivån 1,3μg/m3. Exponeringen för bensen var signifikant associerad till tiden som deltagarna vistats inomhus, utomhus på arbetsplatsen, i rum med rökning samt om de var rökare. Det var marginell skillnad mellan medianhalten uppmätt vid E4:an och den personburna halten (1,6 μg/m3 och 1,5 μg/m3) medan halten på bibliotekstaket låg lägre (1,0 μg/m3). Medianvärdet för butadien var 0,4 μg/m3, vilket är samma som halten uppmätt vid E4:an men högre jämfört med halten på bibliotekstaket (0,12 μg/m3). Det var signifikant skillnad mellan rökare och icke-rökare (p=0,007), och tid som tillbringats i rum med rökning var signifikant förknippat med ökad exponering för butadien. Mätningar genomfördes för både formaldehyd och acetaldehyd, dock redovisas enbart resultaten för formaldehyd på grund av problem med provtagningen av acetaldehyd. Bland mätningarna som genomfördes personburet var medianhalten formaldehyd 15 μg/m3 vilket kan jämföras med resultaten från samma studie i Göteborg förra året (19 μg/m3). Resultatet ligger inom det intervall som angivit som lågrisknivå (IMM, 12-60 μg/m3). Halterna som uppmättes vid E4:an och Biblioteket var nästintill lika (3,5 μg/m3 och 3,0 μg/m3), dock var de betydligt lägre jämfört med den halt som uppmättes personburet. Bostadstyp (villa alt lägenhet), framstod som den enda variabeln som var signifikant associerad till den personburna halten formaldehyd. PAH-mätningarna genomfördes stationärt hemma hos 10 deltagare ur befolkningsurvalet, samt personburet och stationärt på 10 personer i anknytning till forskargruppen. Mediankoncentrationen av bens(a)pyren, mätt personburet, var 0,08 ng/m3 vilket är i nivå med resultaten från Göteborg. Halterna hemma hos personerna från befolkningsurvalet samt de med anknytning till kliniken var 0,17 respektive 0,07 ng/m3. De stationära utomhusmätningarna visade att halten vid E4:an var betydligt högre jämfört med halten på Bibliotekstaket (0,3 respektive 0,1 ng/m3). Kvävedioxid (NO2) mättes som ett lokalt tillägg i syfte att undersöka samband mellan NO2, som trafikindikator, och övriga ämnen. Median halten för mätningarna som gjordes personburet var 8 μg/m3 medan resultaten från de stationära mätningarna var betydligt högre. NO2 uppvisade ingen signifikant korrelation till övriga ämnen mätta personburet. Vidare sågs inga samband till vistelse i specifika miljöer.
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| 12. |
- Modig, Lars, et al.
(författare)
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Cancerframkallande ämnentätortsluft - Umeå 2001
- 2002
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- Exponeringen för ett antal cancerframkallande ämnen undersöktes i ett slumpmässigturval av allmänbefolkningen i Umeå, 2001. Den huvudsakliga studien genomfördesfrån slutet av september till mitten av oktober som personburna 7-dygns mätningar påtotalt 60 personer, medan några av mätningarna genomfördes i januari 2002. Parallelltmed de personburna mätningarna genomfördes även mätningar vid två stationäraplatser i Umeå, bibliotekstaket och E4:an. Mätningarna omfattade bensen, 1,3-butadien, formaldehyd, acetaldehyd, PAH (polyaromatiska kolväten) samtkvävedioxid (NO2). Mätningarna genomfördes med passiva provtagare med undantagför PAH där provtagningen genomfördes med hjälp av en pump.Resultatet från de personburna provtagningarna av bensen gav medianvärdet1,5 μg/m3, vilket kan jämföras med resultatet från fjolårets studie i Göteborg (1μg/m3)och den av Institutet för miljömedicin (IMM) föreslagna lågrisknivån 1,3μg/m3.Exponeringen för bensen var signifikant associerad till tiden som deltagarna vistatsinomhus, utomhus på arbetsplatsen, i rum med rökning samt om de var rökare. Detvar marginell skillnad mellan medianhalten uppmätt vid E4:an och den personburnahalten (1,6 μg/m3 och 1,5 μg/m3) medan halten på bibliotekstaket låg lägre (1,0μg/m3).Medianvärdet för butadien var 0,4 μg/m3, vilket är samma som halten uppmätt vidE4:an men högre jämfört med halten på bibliotekstaket (0,12 μg/m3). Det varsignifikant skillnad mellan rökare och icke-rökare (p=0,007), och tid som tillbringats irum med rökning var signifikant förknippat med ökad exponering för butadien.Mätningar genomfördes för både formaldehyd och acetaldehyd, dock redovisas enbartresultaten för formaldehyd på grund av problem med provtagningen av acetaldehyd.Bland mätningarna som genomfördes personburet var medianhalten formaldehyd15 μg/m3 vilket kan jämföras med resultaten från samma studie i Göteborg förra året(19 μg/m3). Resultatet ligger inom det intervall som angivit som lågrisknivå (IMM,12-60 μg/m3). Halterna som uppmättes vid E4:an och Biblioteket var nästintill lika(3,5 μg/m3 och 3,0 μg/m3), dock var de betydligt lägre jämfört med den halt somuppmättes personburet. Bostadstyp (villa alt lägenhet), framstod som den endavariabeln som var signifikant associerad till den personburna halten formaldehyd.PAH-mätningarna genomfördes stationärt hemma hos 10 deltagare urbefolkningsurvalet, samt personburet och stationärt på 10 personer i anknytning tillforskargruppen. Mediankoncentrationen av bens(a)pyren, mätt personburet, var 0,08ng/m3 vilket är i nivå med resultaten från Göteborg. Halterna hemma hos personernafrån befolkningsurvalet samt de med anknytning till kliniken var 0,17 respektive 0,07ng/m3. De stationära utomhusmätningarna visade att halten vid E4:an var betydligthögre jämfört med halten på Bibliotekstaket (0,3 respektive 0,1 ng/m3).Kvävedioxid (NO2) mättes som ett lokalt tillägg i syfte att undersöka samband mellanNO2, som trafikindikator, och övriga ämnen. Median halten för mätningarna somgjordes personburet var 8 μg/m3 medan resultaten från de stationära mätningarna varbetydligt högre. NO2 uppvisade ingen signifikant korrelation till övriga ämnen mättapersonburet. Vidare sågs inga samband till vistelse i specifika miljöer.
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| 13. |
- Nordenhäll, C, et al.
(författare)
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Airway inflammation following exposure to diesel exhaust : a study of time kinetics using induced sputum
- 2000
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Ingår i: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 15:6, s. 1046-1051
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Tidskriftsartikel (refereegranskat)abstract
- The adverse health effects of particulate matter pollution are of increasing concern. In a recent bronchoscopic study in healthy volunteers, pronounced airway inflammation was detected following exposure to diesel exhaust (DE). The present study was conducted in order to evaluate the time kinetics of the inflammatory response following exposure to DE using induced sputum from healthy volunteers. Fifteen healthy nonsmoking volunteers were exposed to DE particles with a 50% cut-off aerodynamic diameter of 10 microm 300 microg x m(-3) and air for 1 h on two separate occasions. Sputum induction with hypertonic saline was performed 6 and 24 h after each exposure. Analyses of sputum differential cell counts and soluble protein concentrations were performed. Six hours after exposure to DE, a significant increase was found in the percentage of sputum neutrophils (37.7 versus 26.2% p=0.002) together with increases in the concentrations of interleukin-6 (12.0 versus 6.3 pg x mL(-1), p=0.006) and methylhistamine (0.11 versus 0.12 microg x L(-1), p=0.024). Irrespective of exposure, a significant increase was found in the percentage of sputum neutrophils at 24 as compared to 6 h, indicating that the procedure of sputum induction itself may change the composition of sputum. This study demonstrates that exposure to diesel exhaust induces inflammatory response in healthy human airways, represented by an early increase in interleukin-6 and methylhistamine concentration and the percentage of neutrophils. Induced sputum provides a safe tool for the investigation of the inflammatory effects of diesel exhaust, but care must be taken when interpreting results from repeated sputum inductions.
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| 14. |
- Nordenhäll, C, et al.
(författare)
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Diesel exhaust enhances airway responsiveness in asthmatic subjects
- 2001
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Ingår i: European Respiratory Journal. - : European Respiratory Society. - 0903-1936 .- 1399-3003. ; 17:5, s. 909-915
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Tidskriftsartikel (refereegranskat)abstract
- Particulate matter (PM) pollution has been associated with negative health effects, including exacerbations of asthma following exposure to PM peaks. The aim of the present study was to investigate the effects of short-term exposure to diesel exhaust (DE) in asthmatics, by specifically addressing the effects on airway hyperresponsiveness, lung function and airway inflammation. Fourteen nonsmoking, atopic asthmatics with stable disease, on continuous treatment with inhaled corticosteroids, were included. All were hyperresponsive to methacholine. Each subject was exposed to DE (particles with a 50% cut-off aerodynamic diameter of 10 microm (PM10) 300 microg x m(-3)) and air during 1 h on two separate occasions. Lung function was measured before and immediately after the exposures. Sputum induction was performed 6 h, and methacholine inhalation test 24 h, after each exposure. Exposure to DE was associated with a significant increase in the degree of hyperresponsiveness, as compared to after air, of 0.97 doubling concentrations at 24 h after exposure (p < 0.001). DE also induced a significant increase in airway resistance (p=0.004) and in sputum levels of interleukin (IL)-6 (p=0.048). No changes were detected in sputum levels of methyl-histamine, eosinophil cationic protein, myeloperoxidase and IL-8. This study indicated that short-term exposure to diesel exhaust, equal to high ambient levels of particulate matter, is associated with adverse effects in asthmatic airways, even in the presence of inhaled corticosteroid therapy. The increase in airway responsiveness may provide an important link to epidemiological findings of exacerbations of asthma following exposure to particulate matter.
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| 15. |
- Paal, D Molander, et al.
(författare)
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Harmonized Nordic strategies for isocyanate monitoring in workroom atmospheres
- 2002
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 685-687
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Tidskriftsartikel (refereegranskat)abstract
- The Nordic Network on Isocyanates (NORDNI) is financed by the Nordic Council of Ministers and is under the administration of Prof. Yngvar Thomassen and co-workers. National Institute of Occupational Health, Norway. The aim of NORDNI is to establish a broad network between the Nordic National Institutes of Occupational Health working within the field of isocyanate exposure and strategies for sampling and determination of isocyanates in workroom atmospheres. This viewpoint article summarizes the resolutions that were established at the 1st NORDNI consensus meeting arranged in Frøya, Norway, 31st August-2nd September, 2001. The consensus platform from the 1st NORDNI meeting was presented at the 4th International Symposium on Modern Principles of Air Monitoring, Lillehammer, Norway, 3-7 February, 2002.
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| 16. |
- Sandström, K. J. Mattias, et al.
(författare)
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Amperometric biosensor for formic acid in air
- 2000
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Ingår i: Sensors and actuators. B, Chemical. - : Elsevier. - 0925-4005 .- 1873-3077. ; 70:1–3, s. 182-187
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of developing a simple, inexpensive and specific personal passive “real-time” air sampler incorporating a biosensor for formic acid was investigated. The sensor is based on the enzymatic reaction between formic acid and formate dehydrogenase (FDH) with nicotinamide adenine dinucleotide (NAD+) as a co-factor and Meldola's blue as mediator. An effective way to immobilise the enzyme, co-factor and Meldola's blue on screen-printed, disposable, electrodes was found to be in a mixture of glycerol and phosphate buffer covered with a gas-permeable membrane. Steady-state current was reached after 4–15 min and the limit of detection was calculated to be below 1 mg/m3. However, the response decreased by 50% after storage at −15°C for 1 day.
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| 17. |
- Sandström, K. J. Mattias, et al.
(författare)
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Multivariate evaluation of factors influencing the performance of a formic acid biosensor for use in air monitoring
- 2001
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Ingår i: The Analyst. - : Royal Society of Chemistry. - 0003-2654 .- 1364-5528. ; 126:11, s. 2008-2014
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Tidskriftsartikel (refereegranskat)abstract
- A formic acid biosensor for air monitoring has been evaluated using chemometric methods. Using experimental design eleven factors that could influence the performance of the biosensor were examined. The response matrices consisted of six parameters (steady state currents at three different formic acid concentrations and response rates during changes in formic acid concentrations) describing the performance of the biosensor. The data were evaluated using a combination of principal component analysis (PCA) and multiple linear regression (MLR). To confirm the conclusions from the PCA-MLR partial least squares (PLS) was also used. The most important factor for the biosensor performance was found to be the enzyme concentration. Using the information from the chemometric analyses the optimum operation conditions for the biosensor were determined. The steady state currents were increased by 18-30% and the initial two response rates increased by 47-89% compared with a biosensor that had not been optimised.
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| 18. |
- Schulte-Ladbeck, Rasmus, et al.
(författare)
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Characterization of chemical interferences in the determination of unsaturated aldehydes using aromatic hydrazine reagents and liquid chromatography
- 2001
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 3:3, s. 306-310
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Tidskriftsartikel (refereegranskat)abstract
- A systematic investigation on interferences in the determination of unsaturated aldehydes and ketones using the 2,4-dinitrophenylhydrazine (DNPH) method is described. Acrolein, crotonaldehyde, methacrolein and 1-buten-3-one are derivatized with DNPH in the presence of an acidic catalyst to form the respective hydrazones. The unstable hydrazones react with excess reagent to form adducts. These are identified by high-performance liquid chromatography (HPLC)-mass spectrometry and spectroscopic techniques after cryogenic fraction collection of the adducts. The quantification of the unsaturated carbonyls with the DNPH method remains difficult. N-Methyl-4-hydrazino-7-nitrobenzofurazan (MNBDH) was used as an alternative reagent for this purpose. As with DNPH, the formation of a side product is observed. In contrast to DNPH, the alteration of the pH immediately after sampling leads to only one reaction product, which is stable and storable in solution at 4 degrees C for 2 days.
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| 19. |
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| 20. |
- Sunesson, Anna-Lena, et al.
(författare)
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Passive sampling in combination with thermal desorption and gas chromatography as a tool for self-assessment of chemical exposure
- 2002
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 706-710
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Tidskriftsartikel (refereegranskat)abstract
- Diffusive samplers for monitoring of air quality are user-friendly devices that can normally be operated by the user himself. Hence these samplers are suitable for self-assessment. Practical and work organisational aspects of self-assessment of chemical exposure were studied in different occupational settings. It was found that the diffusive sampler used in these studies, the Perkin-Elmer tube in combination with thermal desorption, worked well for the purpose and could be correctly handled by the individuals using it. The results from self-assessments agreed well with expert measurements carried out by an occupational hygienist. However, in order to obtain a sustainable system of self-assessment strong organizational support is needed.
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| 21. |
- von Zweigbergk, Peter, et al.
(författare)
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Development of a diffusive sampling method for determination of methyl isocyanate in air
- 2002
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Ingår i: Journal of Environmental Monitoring. - : Royal Society of Chemistry. - 1464-0325 .- 1464-0333. ; 4:5, s. 663-666
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Tidskriftsartikel (refereegranskat)abstract
- A diffusive sampling method for determination of methyl isocyanate in air has been developed. A glass fibre filter impregnated with 1-(2-methoxyphenyl)piperazine in a commercially available diffusive sampling device was used to collect methyl isocyanate and the derivative formed was analysed with LC-MS/MS. The sampling rate was determined to be 15.6 ml min(-1), with a relative standard deviation of 7.3%. The sampler was validated for sampling periods from 15 min to 8 h, for relative humidities from 20% to 80% and for concentrations from I to 46 microg m(-3). A field validation was also made and the diffusive sampling results showed no difference compared to a pumped reference method. The impregnated filters have to be stored apart from the diffusive sampler housing and loaded into the sampler prior to each sampling.
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