Adaptation of CIP10 for the sampling of 4,4′-methylene diphenyl diisocyanate aerosols

Abstract

Some sampling comparison studies have demonstrated that impinger and filter methods are not adequate for personal sampling of MDI aerosols in fast polymerization reaction processes. Other available sampling techniques for isocyanates have not been characterized for this application. These limitations led to the development of a new sampling method for MDI aerosols. The sampling method recommends a CIP10 device with a configuration in which a centrifuged liquid medium composed of DMPS + MOPIP (0.5 mg mL⁻¹) would collect the MDI aerosols. The DMPS + MOPIP medium was characterized in the laboratory and the MDI–MOPIP monomer and oligomer derivatives were quantitatively extracted using 4 extractions with acetonitrile. Moreover, the DMPS does not prevent the fast reaction between the free MDI and MOPIP, and reaction rates similar to those in an impinger were obtained for the free MDI monomer and oligomers in the DMPS + MOPIP medium. The LOD and LOQ of the method were 0.010 μg mL⁻¹ and 0.033 μg mL⁻¹ respectively. The dynamic range was from 0.079 μg mL⁻¹ to 0.787 μg mL⁻¹ with R² ≥ 0.990. The intra-day and inter-day precisions were <6% for all of the concentration levels tested, and the accuracy was within an appropriate range of 100 ± 6%. No matrix effect was observed, and a total recovery of 98% was obtained. The method under the current conditions optimized in the laboratory appears suitable to be tested in the workplace for MDI aerosol sampling and to be compared in a real situation with an impinger.