| Abstrakt: |
Several methods were used for the sampling and analysis of airborne 1,6-hexamethylene diisocyanate (HDI) and polyisocyanates during spray-painting operations. National Institute for Occupational Safety and Health (NIOSH)Method 5521 uses an impinger filled with 1-(2methoxyphenyl)piperazine in toluene for collection and derivatization, HPLC separation, and simultaneous UV and EC detection. This method was compared directly to Occupational Safety and Health Administration (OSHA) Method 42, which is based on sample collection on a fiber filter coated with 1-(2-pyridyl)piperazine, HPLC separation, then UV detection. NIOSH Method 5521, modified so that polyisocyanate concentrations were determined based on polyisocyanate standards, also was compared with NIOSH Method 0500, which is a gravimetric assay for total particulates. The results for HDI monomer demonstrate that NIOSH Method 5521 appears to give higher results than those obtained using OSHA Method 42, especially when the total particulate concentration is high. Furthermore, field studies show that polyisocyanate concentrations during spray paint operations may exceed a concentration of 1 mg/m3, which is believed to be hazardous. Finally, preliminary results indicate that the true concentration of polyisocyanate in air, in all cases but one, was within two times the theoretical concentration based on the total particulate mass. |
