A Method for Determining Crystalline Silica in Bulk Samples by Fourier Transform Infrared Spectrophotometry

A method for determining crystalline silica (α-quartz) in bulk samples has been developed. This procedure requires the bulk sample to be homogenized and sieved down to particle sizes <10 µm in diameter. The obtained fraction is analysed by Fourier transform infrared spectrophotometry. Method validation was carried out using 55 real-world bulk samples, containing between 1 and 75% (w/w) α-quartz. The method is capable of quantifying α-quartz down to 1% (w/w) in routine analysis. However, the method is unlikely to allow routine quantification at 0.1% (w/w) as currently mandated by regulations.