title: Sampling efficiency of a modified closed-face cassette sampler for airborne toluene diisocyanate determination.
abstract: OBJECTIVE
  A modified closed-face cassette was developed for sampling and derivatizing airborne toluene diisocyanate (TDI).
  
  
  METHODS
  The cassette was assembled as a regular two-piece cassette sampler except that the whole inner surface of the sampler was loaded with coated filters to ensure that all of the aspirated TDI react with 1-(2-pyridyl) piperazine (1-2pp).
  
  
  RESULTS
  A test atmosphere study showed that the sampling efficiencies were 89.4% and 94.3% for 2,4-TDI and 2,6-TDI. One-third of the 2,4-TDI and 2,6-TDI mass was constantly collected on the top and middle-rim filters. A polyurethane (PU)-manufacturing plant study revealed an average of 35% and 33% of both isomer masses collected on the top and middle-rim filters. The 2,4-TDI collection of the closed-face cassette sampling was 21% higher than that of open-face sampling. Furthermore, consistent isomeric compositions of airborne 2,4-/2,6-TDI obtained from both types of samplers validated the use of the modified cassette sampler.
  
  
  CONCLUSIONS
  The closed-face cassette sampler is capable of a higher collection of airborne TDI and the technique involved is as simple and feasible as that of the open-face sampler.
authors: Institute of Environmental Health Sciences, College of Medicine, National Yang-Ming University, Shi-Pai, Taipei, Taiwan.
authors: I F
authors: IF
authors: Mao
authors: M L
authors: ML
authors: Chen
authors: Y C
authors: YC
authors: Lin
mesh_terms: D000395:Air Pollutants, Occupational / Q000032:analysis*; D002853:Chromatography, Liquid; D004784:Environmental Monitoring / Q000295:instrumentation; D005374:Filtration; D007202:Indicators and Reagents; D014051:Toluene 2,4-Diisocyanate / Q000032:analysis*
chemical_list: D000395:Air Pollutants, Occupational; D007202:Indicators and Reagents; D014051:Toluene 2,4-Diisocyanate