The purpose of this study was to compare performances of two analytical methods, the OSHA 42 and two NIOSH 5522, of quantifying total isocyanates in ar. These methods were compared in terms of accuracy and precision and the detection limits using four(4) spiked samples in each of four(4) concentration levels which ranged from 0.25 to 2.0 times of the ACGIH TLV-TWA.
In addition, two methods were used to assess airborne concentrations of total isocyanates at the following processes including autobody spray painting, furniture spray painting, polyurethane foaming, urethane adhesion, UV coating, and pigment mixing.
The results of this study showed that the NIOSH 5522 method was better than the OSHA 42 method in terms of accuracy, precision, and detection limit for quantifying airborne total isocyanates. It was also clear that the NIOSH method was capable of detecting not only monomeric but also non-monomeric isocyanates. The results of air concentrations of total isocyanates among processes studied indicate that some processes may exceed the recommended level of isocyanates.
In addition, to evaluate toxicological effects of total isocyanates, it is recommended to consider additive effects of isocyanates present in mixtures.
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