Transitioning from Univariate to Multivariate Predictive Models for Respirable Quartz via Infrared Spectroscopy

Ernest N. Morial New Orleans Convention Center 

The quantification of quartz in respirable dust samples is possible using a variety of established analytical methods. These methods have been established by national institutions, such as the National Institute for Occupational Safety and Health (NIOSH), standardization bodies, such as the American Society for Testing and Materials (ASTM International), and the International Organization for Standardization (ISO). These methods are generally based on either X-ray diffraction or infrared spectroscopy analytical techniques. The analysis is executed either directly on the filter used for sampling or after extraction of the sample and redeposition on new media. Every method is calibrated, independently of the analytical technique or preparation of the sample, using samples of a known quantity of material characterized by high purity quartz. In addition, every method is calibrated using a quantification model based on univariate calibration. The response of the analytical technique is condensed into one variable, typically the height or area of the region of interest. The values for the selected variable for different standard reference or calibration samples are correlated with the known amount of quartz in the same samples. The resulting regression becomes the calibration model and the quantification model for future unknown samples. While this approach is well established and validated, it does not take advantage of the full potential of the data created by modern diffractomet

"R. Walker, NIOSH, Pittsburgh, PA, USA
C. Wolfe, NIOSH, Pittsburgh, PA, USA
M. Yekich, NIOSH, Pittsburgh, PA, USA
E. Cauda, NIOSH, Pittsburgh, PA, USA"
 

"The authors would like to thank Dr. Lauren Chubb for the initial involvement in the study and Dr. Sena Yang for the support in the very last phase of the study.

L. Chubb, NIOSH, Pittsburgh, PA, USA
S. Yang, NIOSH, Pittsburgh, PA, USA

References used in the manuscript can be presented as well."
 

Exposure Assessment

Respiratory protection