Non-targeted crystal phase screening strategy and Rietveld refinement application based on complex dust samples in occupational settings

BackgroundOccupational health places often involve complex dust samples characterized by diverse compositions and a lack of prior supplementary information. These factors pose challengs in ascertaining crystal phase composition, creating a hurdle for both crystallographic screening and subsequent precise quantification. Hence, establishing a systematic, non-targeted crystal phase screening strategy is essential for analyzing complex occupational dust samples lacking background data.ObjectiveTo develop a non-targeted crystal phase screening strategy and a corresponding evaluation mechanism for complex occupational dust, by leveraging various non-destructive spectroscopy techniques and automated full-spectrum fitting, aiming to establish a technical foundation for phases identification and standardless quantification in samples with unknown backgrounds. MethodsAn extensible and non-targeted screening strategy and a dual-verification mechanism were formulated specifically for occupational health samples. The approach integrated energy dispersive X-ray fluorescence spectroscopy (EDXRF), Fourier-transform infrared (FTIR), and Raman spectroscopy to ensure accurate phase identification. To demonstrate applicability, a representative routine monitoring sample was analyzed. The strategy was validated based on the precision of Rietveld refinement results and the logical consistency of phase distribution within specific occupational settings. Furthermore, universality was tested across multiple industrial sectors prone to silica-related dust, including refractory material manufacturing, construction stone processing, and steel rolling. ResultsUtilizing high-precision X-ray diffraction (XRD) data from a representative complex dust sample, a comprehensive workflow comprising primary component identification, sequential phase screening, and gap-filling analysis successfully identified 13 highly correlated crystal phases, 11 of which exhibited strong industry relevance. Subsequent to these screening results, Rietveld full-spectrum fitting yielded a calculated pattern closely matching the experimental data, with a relatively flat residual line and high statistical reliability (Rwp=5.121%, Rexp=2.955%, and χ2=1.733). In universality tests across various industrial sites, all samples achieved Rwp < 20% and χ2 <2. In addition, the quantitative phase distributions remained self-consistent and highly aligned with actual industrial processes and material positioning. ConclusionA crystal phase screening strategy combining multi-modal spectroscopic analysis with computer-aided full-spectrum fitting is successfully established. This method effectively identifies multiple crystalline substances in uninformed samples and achieves non-targeted screening of complex occupational dust samples. Validated through both numerical accuracy and phase distribution, the strategy provides a practical and robust methodological framework for analyzing complex occupational dust samples without background information.