Fan Wenxia Wendy, Gualtieri Alessandro F, Hamilton Ayrton, Patel Janki P, Salmond Jennifer A
School of Environment, Faculty of Science, University of Auckland, Auckland, New Zealand.
Department of Chemical and Geological Sciences, The University of Modena and Reggio Emilia, Via G. Campi 103, Modena, 41125, Italy.
Sci Rep. 2025 Jul 13;15(1):25316. doi: 10.1038/s41598-025-09551-5.
Erionite is a fibrous zeolite classified as a Group 1 carcinogen and may pose a significant public health hazard when aerosolized into individual respirable-sized fibers. SEM-EDXA has been widely used to identify individual erionite fibers in environmental samples as it combines morphological imaging with elemental analysis. However, the reliability of SEM-EDXA data when applied to the quantitative chemical analysis of individual erionite fibers rather than bulk samples remains uncertain. This study analyzed 325 individual erionite fibers (obtained from a bulk sample with high-purity) across a range of fiber widths and four commonly used sample preparation methods, using two different SEM-EDS systems. SEM-EDXA results were compared with previously acquired EPMA reference data from the bulk sample to assess analytical accuracy. Systematic overestimations of Si and Mg and underestimations of Al, K, and Ca were observed. Framework elements (Si and Al) exhibited relatively stable detection in fibers > 0.5 μm. However, preparation methods-deionized water dispersion and hydrogen peroxide digestion-introduced greater variability, likely due to ion exchange and cation mobilization. Despite the purity of the erionite bulk sample, none of the analyzed individual fibers fully met the established quantitative chemical criteria for erionite identification. These results highlight the need for pre-calibration with erionite standards and the application of correction index to improve SEM-EDX accuracy, and subsequent confirmation of mineralogy using TEM-SAED, when determining whether individual fibers found in airborne samples are erionite.
毛沸石是一种纤维状沸石，被归类为1类致癌物，当雾化成可吸入的单根纤维时，可能对公众健康构成重大危害。扫描电子显微镜-能量色散X射线分析（SEM-EDXA）已被广泛用于识别环境样品中的单根毛沸石纤维，因为它将形态成像与元素分析结合在一起。然而，当应用于单根毛沸石纤维而非大量样品的定量化学分析时，SEM-EDXA数据的可靠性仍不确定。本研究使用两种不同的扫描电子显微镜-能量色散X射线光谱（SEM-EDS）系统，分析了325根单根毛沸石纤维（从高纯度大量样品中获得），这些纤维具有一系列纤维宽度，并采用了四种常用的样品制备方法。将SEM-EDXA结果与之前从大量样品中获得的电子探针微区分析（EPMA）参考数据进行比较，以评估分析准确性。观察到硅（Si）和镁（Mg）的系统高估以及铝（Al）、钾（K）和钙（Ca）的低估。骨架元素（Si和Al）在大于0.5μm的纤维中表现出相对稳定的检测。然而，去离子水分散和过氧化氢消解等制备方法引入了更大的变异性，可能是由于离子交换和阳离子迁移。尽管毛沸石大量样品纯度高，但分析的单根纤维均未完全符合既定的毛沸石识别定量化学标准。这些结果突出表明，在确定空气样品中发现的单根纤维是否为毛沸石时，需要用毛沸石标准进行预校准并应用校正指数来提高SEM-EDX的准确性，随后使用透射电子显微镜-选区电子衍射（TEM-SAED）确认矿物学。
