Investigation of the determination of respirable quartz on filter media using fourier transform infrared spectrophotometry.
Appl Occup Environ Hyg 1990 Jun; 5(6):348-348
The feasibility of using Fourier Transform infrared spectrophotometry (FTIR) to determine respirable quartz (14808607) directly on filters was examined. Various types of filters were spiked with suspensions of quartz. Some samples contained broadband interferents such as coal dust or structural interferences such as cristobalite or kaolinite. The calibrant consisted of standard reference method 1878 quartz which was used at concentrations of 20 to 1000 micrograms (microg) per filter. The samples were analyzed by FTIR spectrophotometry. The absorbances were measured by determining peak height after subtraction of the estimated filter contribution, determining peak height after spectral subtraction of the filter contribution, and determining the integrated absorbance after subtraction of the filter contribution. Polyvinyl-chloride copolymer based filters had the lowest absolute absorbance and made the smallest contribution to the sample absorbances. The presence of the broadband or structural interferences led to the quartz concentrations being underestimated by 6 to 9 and up to 20%, respectively. Both spectral subtraction and estimation from correction curves were found to overcorrect for the amount of interference and resulted in a negative bias in the quantitation of quartz. The author concludes that FTIR used for direct on filter analysis of quartz does not offer any significant improvement over existing IR methods for determining quartz.
NIOSH-Author; Analytical-methods; Quartz-dust; Air-filters; Infrared-spectroscopy; Industrial-hygiene; Quantitative-analysis; Respirable-dust
Applied Occupational and Environmental Hygiene