| 1. |
- Jönsson, Bo A, et al.
(författare)
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Determination of hexahydrophthalic anhydride in air using gas chromatography
- 1991
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Ingår i: Journal of Chromatography A. - 0021-9673. ; 558:1, s. 247-256
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Tidskriftsartikel (refereegranskat)abstract
- Two methods for the determination of hexahydrophthalic anhydride (HHPA) in air were developed. In a solid sorbent method, HHPA was sampled in Amberlite XAD-2 tubes, eluted in toluene and analysed by gas chromatography with flame ionization detection. The sampling rates were 0.2 and 1.0 l/min. At 15 micrograms/m3 (relative humidity less than 2%) and 27 micrograms/m3 (relative humidity 70%) no breakthrough was observed. However, at 160 micrograms/m3 (relative humidity less than 2%), 6% breakthrough was found. The sampling efficiency of the sampling rates 0.2 and 1.0 l/min did not differ. In a bubbler method, HHPA was sampled in bubblers filled with 0.1 M sodium hydroxide solution. The sodium salt of hexahydrophthalic acid was formed. No breakthrough was observed using a sampling rate of 1.0 l/min. The samples were stable during storage for eight weeks in a refrigerator. The HHP acid was esterified with methanol-boron trifluoride and analysed by gas chromatography-flame ionization detection. Apparatus for the generation of standard atmospheres of HHPA, in the range of 10-3000 micrograms/m3, was developed using the diffusion principle. For the solid sorbent method the precision (coefficient of variation) of the overall method was 2-7%, and for the bubbler method 3-19% (range 15-160 micrograms HHPA/m3; relative humidity = less than 2-70%). A comparison between the two methods was performed using the standard atmosphere. The concentrations found by the solid sorbent method were 86-98% of those found by the bubbler method (range 15-160 micrograms HHPA per m3; relative humidity = less than 2-70%). In work environment air, 93% was found using the solid sorbent method relative to the bubbler method at a mean concentration of 330 micrograms/m3 (coefficient of variation = 39%; range 200-540 micrograms/m3). For both methods, concentrations greater than 3 micrograms/m3 could be quantified at 60 min sampling with a sampling rate of 1.0 l/min.
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| 2. |
- Jönsson, Bo A, et al.
(författare)
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Generation of hexahydrophthalic anhydride atmospheres in a controlled human-use test chamber
- 1994
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Ingår i: American Industrial Hygiene Association Journal. - : Informa UK Limited. - 1542-8117 .- 0002-8894. ; 55:4, s. 330-338
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Tidskriftsartikel (refereegranskat)abstract
- A method for generating controlled atmospheres of hexahydrophthalic anhydride (HHPA) in an 8 m3 exposure chamber was developed. The permeation principle was used for gaseous HHPA generation. HHPA concentration was monitored by sampling on XAD-2 tubes and by a Fourier-transform infrared (FTIR) spectrometer using the partial least-square quantitative method. The repeatability of the FTIR was 5%, the reproducibility 12%, and the limit of detection 10 micrograms/m3. A bubbler method determined the sum of HHPA and HHP acid by using gas chromatography/mass spectrometry detection after derivatization with methanol/boron trifluoride. The precision of the work-up procedure was 3% and the recovery was 94% at 300 ng sampled amount of HHPA. The limit of detection was 10 ng HHPA. The variation in the permeation rate was 3% over 3 days. Different concentrations in the exposure chamber were generated by changing the temperature of the permeation tubes. The generated HHPA concentration range, at human exposure, was 3-90 micrograms/m3. The concentration at one temperature was reproducible even after major changes in the temperature. The coefficient of variation (CV) of six samples from different places in the breathing zone was 3%. The variation in the concentration, during an 8-hour human exposure at 10 micrograms/m3, was 3%. Time-weighted averages (8 hour) for human exposures of 10 micrograms/m3 (CV = 15%; n = 6); 37 micrograms/m3 (CV = 5%; n = 5); and 81 micrograms/m3 (CV = 6%; n = 9) were obtained at intended concentrations of 10 micrograms/m3, 40 micrograms/m3, and 80 micrograms/m3. The loss of HHPA in the exposure chamber was 54% (CV = 17%).(ABSTRACT TRUNCATED AT 250 WORDS)
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| 3. |
- Jönsson, Bo A, et al.
(författare)
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Hexahydrophthalic acid in urine as an index of exposure to hexahydrophthalic anhydride
- 1991
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Ingår i: International Archives of Occupational and Environmental Health. - 1432-1246. ; 63:1, s. 77-79
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Tidskriftsartikel (refereegranskat)abstract
- Post-shift and next-morning urine was sampled from workers exposed to hexahydrophtalic anhydride (HHPA), an epoxy hardener, sensitising at low exposure levels. Exposure levels of HHPA in air (gas chromatography, GC) in the range of 30-270 micrograms/m3 corresponded to urinary concentrations of 0.9-2.8 mumol hexahydrophthalic acid (HHP acid; GC-mass spectrometry)/mmol creatinine. In the morning samples the concentrations were less than 0.04-0.3 mumol HHP acid/mmol creatinine. In unexposed controls, the level was less than 0.1 mumol/mmol creatinine. A correlation was found between the time-weighted levels of HHPA in air and HHP acid in the post-shift urine (rs = 0.93; P less than 0.023), indicating that the determination of HHP acid in urine is suitable for biologic monitoring of HHPA exposure.
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| 4. |
- Jönsson, Bo A, et al.
(författare)
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Method for the biological monitoring of hexahydrophthalic anhydride by the determination of hexahydrophthalic acid in urine using gas chromatography and selected-ion monitoring
- 1991
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Ingår i: Journal of Chromatography A. - 0021-9673. ; 572:1-2, s. 117-131
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Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of hexahydrophthalic acid, a metabolite of hexahydrophthalic anhydride, in human urine has been developed. The urine was worked-up by liquid-solid extraction, esterified with boron trifluoride-methanol, and analysed by capillary gas chromatography and selected-ion monitoring. Hexadeuterium-labelled hexahydrophthalic acid was used as the internal standard. The precision was 4% at 0.7 microgram/ml and 5% at 0.07 microgram/ml. The recovery of the acid for the overall method was 101% at 0.07 micrograms/ml of urine (with a coefficient of variation of 4%) and 95% at 0.7 microgram/ml (coefficient of variation 2%). The limit of detection was 20 ng/ml urine.
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| 5. |
- Jönsson, Bo A, et al.
(författare)
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Occupational exposure to hexahydrophthalic anhydride: air analysis, percutaneous absorption, and biological monitoring
- 1993
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Ingår i: International Archives of Occupational and Environmental Health. - 1432-1246. ; 65:1, s. 43-47
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Tidskriftsartikel (refereegranskat)abstract
- Urinary hexahydrophthalic acid (HHP acid) levels were determined in 20 workers occupationally exposed to hexahydrophthalic anhydride (HHPA) air levels of 11-220 micrograms/m3. The levels of HHP acid in urine increased rapidly during exposure and the decreases were also rapid after the end of exposure. The elimination half-time of HHP acid was 5 h, which was significantly longer than in experimentally exposed volunteers, possibly indicating distribution to more than one compartment. There was a close correlation between time-weighted average levels of HHPA in air and creatinine-adjusted levels of HHP acid in urine collected during the last 4 h of exposure (r = 0.90), indicating that determination of urinary HHP acid levels is suitable as a method for biological monitoring of HHPA exposure. An air level of 100 micrograms/m3 corresponded to a postshift urinary HHP acid level of ca. 900 nmol/mmol creatinine in subjects performing light work for 8 h. Percutaneous absorption of HHPA was studied by application of HHPA in petrolatum to the back skin of three volunteers. The excreted amounts of HHP acid in urine, as a fraction of the totally applied amount of HHPA, were within intervals of 1.4%-4.5%, 0.2%-1.3%, and 0%-0.4% respectively, indicating that the contribution from percutaneous absorption is of minor importance in a method for biological monitoring.
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| 6. |
- Jönsson, Bo A, et al.
(författare)
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Toxicokinetics and biological monitoring in experimental exposure of humans to gaseous hexahydrophthalic anhydride
- 1993
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140. ; 19:3, s. 183-190
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Tidskriftsartikel (refereegranskat)abstract
- Six healthy volunteers were exposed to gaseous hexahydrophthalic anhydride (HHPA) concentrations of 10, 40, or 80 micrograms.m-3 (65, 260 or 520 nmol.m-3, respectively) for 8 h. The respiratory uptake of the inhaled HHPA was almost complete. Rapid increases in plasma and urinary levels of hexahydrophthalic acid (HHP acid) were seen. During the first 4 h after the end of exposure, the half-time of HHP acid in plasma was about 2 h. A corresponding decay was seen in urine. The correlations (r > 0.90) between the air concentrations of HHPA and the levels of HHP acid in plasma and urine were close. They were even closer (r > 0.96) when the total respiratory uptake of HHPA was used. Urinary pH adjustment by intake of ammonium chloride or sodium hydrogen carbonate did not significantly alter the excretion of HHP acid. The results show that the analysis of HHP acid in plasma or urine is useful as a biological monitor for exposure to HHPA.
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| 7. |
- Lindh, Christian, et al.
(författare)
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Method for analysis of methyltetrahydrophthalic acid in urine using gas chromatography and selected ion monitoring
- 1994
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Ingår i: Journal of chromatography. B, Biomedical applications. - : Elsevier BV. - 1572-6495 .- 0378-4347. ; 660:1, s. 57-66
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Tidskriftsartikel (refereegranskat)abstract
- A method for the determination of methyltetrahydrophthalic acid (MTHP acid), a metabolite of methyltetrahydrophthalic anhydride (MTHPA) in human urine, was developed. The investigated MTHP acid was obtained by hydrolysis of a commercial MTHPA mixture, composed of three major isomers. These were synthesized and identified as 3-methyl-delta 4-tetrahydrophthalic anhydride, 4-methyl-delta 4-tetrahydrophthalic anhydride and 4-methyl-delta 3-tetrahydrophthalic anhydride. The urine was worked up by a liquid-solid extraction technique using C18 sorbent columns. Esterification was performed with methanol and boron trifluoride. The derivative in toluene was analyzed with capillary gas chromatography and selected ion monitoring. Deuterium-labeled MTHP acid was used as internal standard. The intra-assay precision for the overall method was between 4 and 8% in the range 3-110 ng/ml and the inter-assay precision was between 4 and 7% in the range 30-110 ng/ml. The total recoveries of the MTHP acid at 19 and 190 ng/ml were 94 and 97%, respectively. The total detection limit for the three isomers was < 6 ng/ml. Analysis of urine from a worker exposed to MTHPA makes it reasonable to assume that the method may be used for biological monitoring of MTHPA exposure.
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| 8. |
- Welinder, Hans, et al.
(författare)
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Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride in exposed workers
- 1994
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Ingår i: Scandinavian Journal of Work, Environment and Health. - 0355-3140. ; 20:6, s. 459-465
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES--Exposure-response relationships in the formation of specific antibodies to hexahydrophthalic anhydride (HHPA) was studied in exposed workers. METHODS--The relation between exposure to HHPA and the levels of specific immunoglobin E [(radioallergosorbent test (RAST)] and immunoglobin G (enzyme-linked immunosorbent assay) antibodies was investigated in a cross-sectional study on 95 workers from two plants using epoxy resin with HHPA as a hardener; the mean time of exposure was 7 (range 0.1-25) years. RESULTS--The specific immunoglobin E and immunoglobin G was significantly increased in exposed workers when they were compared with unexposed workers or external referents. There was no significant difference in the number of RAST positives [N = 23 (24%)] between the groups of workers exposed to < 10 micrograms.m-3, 10--< 50 micrograms.m-3, or > or = 50 micrograms.m-3. No effects were found of atopy or smoking habits on the prevalence of RAST positives. Five out of seven workers positive for immunoglobulin E in the group with the lowest exposures reported frequent short-time (minutes per day) exposures exceeding 50 micrograms.m-3. A correlation was seen between specific immunoglobulin E and G antibodies (rs = 0.5). CONCLUSIONS--The results indicate that HHPA is a sensitizing compound even at low exposure levels and that short-time peak exposures may have an impact on immunoglobulin E sensitization.
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