Factors Affecting the Accuracy of Airborne Quartz Determination

Abstract

Samples collected in a foundry were used to analyze sources of variation and factors influencing the overall accuracy of sampling results. Air samples were analyzed by Fourier Transform Infrared Spectroscopy (FTIR) using NIOSH Method 7602 to study particle size effects, analytical precision, sampling equipment performance, and production factors. The FTIR technique provides accuracy when silica particle size is taken into consideration. In this case, the variability due to analytical factors is small compared with other sources of error. The typical coefficient of variation of the analytical procedure is 0.08; variation associated with sampling reaches 0.21; and interday coefficient of variation can be as high as 0.48. The IR method has advantages over XRD analysis, including cost effectiveness, sensitivity, and a lower detection limit.

Keywords:

• α-quartz
• FTIR
• IR spectrometry
• respirable particulates
• silica

ACKNOWLEDGMENTS

The authors acknowledge the contribution of M. Sheppard, S. Hache and M. Zaidi for collecting field samples. We also thank Serge Zuev for sharing his experience in experimental statistics.

Notes

^A Reference material is used without any additional separation.

^B Reference material is purified by consecutive extraction with 10% NaOH and 10% HCl solutions.

^A Results estimated for the chart published by Bhaskar et al.[5]

^B Size selected as reference point.