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Med. Pr. 2001;52(5)

Free crystalline silica: Possibilities and limitations of its detection and determination in dust using infrared spectrometry

Wolna krystaliczna krzemionka - możliwości i ograniczenia wykrywania oraz oznaczania w pyłach metodą fourierowskiej spektrometri

A. Maciejewska

Abstract

The effect of the commonly occurring industrial dust components on the detection of crystalline silica and crystobalite by means of infrared spectrometry was investigated. The influence of minerals interfering in infrared with quartz and crystobalite: kaolinite, microcline, albite, mullite, and amorphous silica, as well as of the mixture of SiO₂ crystalline forms was analyzed. The study was based on the computer-aided summing up of crystalline silica spectra with spectra of interfering components and spectra resulting from further transformation:deconvolved spectra,the second and fourth orders derivative spectra.
It was found that the smallest amount of silica, possible to be detected in mixtures with interfering components amounted to1-5%and crystobalite to 2-10%. The limit of detection, using the pellet technique in the adopted conditions of spectra registration, accounted for 0.5 ľg for silica and 1 ľg for crystobalite, whereas using PVC filters, 1 ľg of silica and 4 ľg of crystobalite could be detected.

Key words

crystalline silica, quartz, crystobalite, infrared spectrometry