Evaluation of solid phase extraction (SPE) for the analysis of isocyanates in spray-painting operations
Perez, Gregory P.
Polyisocyanates of 1,6-hexamethylene diisocyanate (HDI) were initially introduced as an alternative to HDI monomer for use in polyurethane paint. The chemical class of isocyanates is utilized in polyurethane paints as a cross-linking agent, which imparts the favorable, characteristics of hardness and durability to the product. However, workers who are exposed to the aerosolized isocyanates during the spray-painting process are subject to irritation of the eyes, skin and respiratory tract which may result in occupational asthma. Several researchers have investigated the use of a polyurethane sponge impregnated with a derivatizing solution. A novel solvent for this method would have the characteristics of being high boiling, viscous, non-hazardous and non-reactive. Butyl benzoate is a solvent which exhibits such advantageous characteristics. However, the low volatility of butyl benzoate hinders solvent removal for analysis. A sample processing technique has been developed that incorporates solid phase extraction (SPE) to effect the separation of the solvent from the analyte. Through the utilization of solid phase extraction, separation of derivatized isocyanates from various interferents has been affected. Solid phase extraction simultaneously affords physical separation of particulate matter, solvent removal and preferential elution of analytes. This technique has been integrated with previously studied analytical methods to yield a combined process, which has the benefits of an extremely favorable solvent and interferent reduction via SPE.
extraction, isocyanates, spray painting, solid phase extraction
Perez, G. P. (1998). Evaluation of solid phase extraction (SPE) for the analysis of isocyanates in spray-painting operations (Unpublished thesis). Southwest Texas State University, San Marcos, Texas.