A method for determining crystalline silica in bulk samples by Fourier transform infrared spectrophotometry.

A method for determining crystalline silica (alpha-quartz) in bulk samples has been developed. This procedure requires the bulk sample to be homogenized and sieved down to particle sizes <10 micro m 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) alpha-quartz. The method is capable of quantifying alpha-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.