Christa Gorski

Project title: A Comparison of Surface Sampling Wipe Media for Isocyanate Sampling in the Auto Repair Industry

Degree: MS | Program: Occupational & Environmental Exposure Sciences (OEES) - no longer offered | Project type: Thesis/Dissertation
Completed in: 2012 | Faculty advisor: Michael G. Yost


Objective: many opportunities exist for dermal exposure to isocyanates in the auto repair industry. Contaminated work surfaces may be of particular concern as surfaces sprayed with isocyanates have been shown to represent a source of exposure long after paints and clear coats have dried. Improvement upon currently used surface sampling methods may be important in evaluating work surfaces as a potential source of isocyanate exposure. In order to initiate these improvements, this study aims to compare multiple wipe media to find a material effective in recovering isocyanates.

Methods: percent recovery of isocyanates was compared among 3 different wipe media composed of the following materials: PVDF, quartz fiber, and polypropylene. In addition, each wipe material was sampled from 3 surface type, including glass, ceramic, and aluminum. All wipe samples were analyzed using a quantitative HPLC assay at the Industrial Hygiene lab at the Washington State Department of Labor and Industries. Statistical analysis was used to determine whether differences in recovery of hexamethylene diisocyanates (HDI) could be attributed to differences in wipe media or surface type.

Results: comparison of PVDF and quartz fiber media found that difference in recovered isocyanates species could not be explained by differences in the wipes. In contrast, a significant decline in mean recovery was observed when comparing polypropylene wipes to PVDF and quartz media. Surface type was also found to be a significant factor in determining isocyanate recovery. Samples taken from aluminum surfaces yielded the highest recovery of HDI.

Conclusion: although PVDF and quartz media appeared to be associated with similar recovery of HDI, quartz wipes are not recommended for surface sampling due to durability issues. Since HDI recovery when using PVDF wipes is significantly higher compared to that of polypropylene media, PVDF may be an effective material for surface sampling.