title: Determination of hexahydrophthalic anhydride in air using gas chromatography.
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.
authors.affiliation: Department of Occupational and Environmental Medicine, University Hospital, Lund, Sweden.
authors.forename: B
authors.initials: B
authors.lastname: Jönsson
authors.forename: H
authors.initials: H
authors.lastname: Welinder
authors.forename: G
authors.initials: G
authors.lastname: Skarping
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D002849:Chromatography, Gas / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D004355:Drug Stability; D004853:Epoxy Resins / Q000032:analysis*; D004951:Esterification; D010796:Phthalic Anhydrides / Q000032:analysis*
chemical_list: D000395:Air Pollutants, Occupational; D004853:Epoxy Resins; D010796:Phthalic Anhydrides; C005752:araldite