Quantitative determination of the quartz content of respirable dust by infrared spectrophotometry

Infrared spectrophotometric method was developed for the determination of crystalline silica in respirable dust samples from a wide range of industrial environments. Samples were collected with personal sampler on a Microsorban filter. The filter was dissolved in benzene and the suspension was separated by centrifuge. The mineral phase content of the dust was determined by X-ray powder diffraction. The particle size of the standards and samples as well as the mineral interference effects were controlled. Different calibration curves using a mixture of crystalline quartz and interference mineral were prepared. The particle size was measured in the pellets. The absorbance of the 800 cm−1 band (Si−O−Si symmetrical stretching vibration) was calculated and proved to be proportional to the concentration of quartz.