Milling effects upon quantitative determinations of chrysotile asbestos by the reference intensity ratio method

As is well known from literature, the grinding process, which is an unavoidable step in sample preparation, may strongly modify the physical properties of chrysotile through amorphisation. The aim of this work is to establish the proper milling time to apply to the samples before all accurate X-ray powder diffraction quantitative analysis. We have used the RIR (reference intensity ratio) analytical method, based on the measurement of the ratio I/I-s between the intensity of the strongest line of an analyte and the intensity of the analytical peak of a standard material, when they are thoroughly mixed 50:50 by weight. We have studied how the RIR value changes as a function of the milling time of the sample and how the accuracy of this: quantitative method is affected. (C) 2000 International Center for Diffraction Data. [S0885-7156(99)00203-1].