Trace metals in ambient particulate matter and cloud are considered key elements of atmospheric processes as they affect air quality, environmental ecosystems, and cloud formation. However, they are often available at trace concentrations in these media such that their analysis requires high-precision and sensitive techniques. In this study, different analytical methods were applied to quantify trace metals in particulate matter (PM) samples collected on quartz and polycarbonate filters as well as cloud water, using the Total reflection X-Ray Fluorescence (TXRF) technique. These methods considered the measurement of filter samples directly without and with chemical pretreatment. Direct measurements involved the analysis of PM samples collected on polycarbonate filters and cloud water samples after they are brought onto TXRF carrier substrates. The chemical treatment method involved the assessment of different acid digestion procedures on PM sampled on quartz filters. The solutions applied were reverse aqua regia, nitric acid, and a combination of nitric acid and hydrogen peroxide. The effect of cold-plasma treatment of samples on polycarbonate filters before TXRF measurements was also investigated. Digestion with the reverse aqua regia solution provided lower blanks and higher recovery in comparison to other tested procedures. The detection limits of the elements ranged from 0.3 to 44 ng cm⁻². Ca, K, Zn, and Fe showed the highest detection limits of 44, 35, 6, and 1 ng cm⁻², while As and Se had the lowest of 0.3 and 0.8 ng cm⁻², respectively. The method showed higher recovery for most trace metals when applied to commercially available reference materials and field samples. TXRF measurements showed good agreement with results obtained from ion chromatography measurements for elements such as Ca and K. Cold-plasma treatment did not significantly lead to an increase in the detected concentration, and the results were element specific. Baking of the quartz filters prior to sampling showed a reduction of more than 20 % of the filter blanks for elements such as V, Sr, Mn, Zn, and Sb. The methods were applied successfully on ambient particulate matter and cloud water samples collected from the Atlas Mohammed V station in Morocco and the Cape Verde Atmospheric Observatory. The obtained concentrations were within the range reported using different techniques from similar remote and background regions elsewhere, especially for elements of anthropogenic origins such as V, Pb, and Zn with concentrations of up to 10, 19, and 28 ng m⁻³, respectively. Enrichment factor analysis indicated that crustal matter dominated the abundance of most of the elements, while anthropogenic activities also contributed to the abundance of elements such as Sb, Se, and Pb. The results confirm that TXRF is a useful complementary sensitive technique for trace metal analysis of particulate matter in the microgram range as well as in cloud water droplets.

中文翻译：

---

TXRF在监测颗粒物和云水中痕量金属中的应用

环境颗粒物和云中的痕量金属被认为是大气过程的关键元素，因为它们会影响空气质量，环境生态系统和云的形成。但是，它们通常在这些介质中以痕量浓度存在，因此其分析需要高精度和灵敏的技术。在这项研究中，使用全反射X射线荧光（TXRF）技术，采用了不同的分析方法来量化从石英和聚碳酸酯滤池以及云水中收集的颗粒物（PM）样品中的痕量金属。这些方法考虑了在不使用化学预处理的情况下直接测量过滤器样品的方法。直接测量涉及将收集在聚碳酸酯过滤器上的PM样品和浊水样品带到TXRF载体基底上后的分析。化学处理方法包括对石英过滤器上采样的PM的不同酸消解程序进行评估。应用的溶液是反向王水，硝酸以及硝酸和过氧化氢的混合物。还研究了TXRF测量之前样品在聚碳酸酯过滤器上进行冷等离子体处理的效果。与其他测试程序相比，使用反向王水溶液进行消化可以减少空白，并提高回收率。元素的检出限为0.3至44 ng cm 还研究了在TXRF测量之前对聚碳酸酯过滤器进行样品的冷等离子体处理的效果。与其他测试程序相比，使用反向王水溶液进行消化可以减少空白，并提高回收率。元素的检出限为0.3至44 ng cm 还研究了在TXRF测量之前对聚碳酸酯过滤器进行样品的冷等离子体处理的效果。与其他测试程序相比，使用反向王水溶液进行消化可以减少空白，并提高回收率。元素的检出限为0.3至44 ng cm⁻²。Ca， K， Zn和Fe的最高检出限分别为44、35、6和1 ng cm ^-2，而As和Se的最低检出限分别为0.3和0.8 ng cm ^-2。当应用于市售参考材料和现场样品时，该方法对大多数痕量金属显示出更高的回收率。TXRF测量结果与从离子色谱法测量的元素（如Ca和K）获得的结果吻合良好。冷等离子体处理并没有明显导致所检测浓度的增加，并且结果是元素特异性的。取样之前，对石英过滤器进行烘烤显示，对于V，Sr，Mn，Zn和Sb等元素，过滤器坯料减少了20％以上。该方法已成功应用于从摩洛哥阿特拉斯·穆罕默德五世站和佛得角大气天文台收集的周围颗粒物和云水样品。所获得的浓度在使用不同技术从其他类似的偏远地区和本底地区报告的范围内，尤其是对于人为来源的元素（例如V，Pb和Zn的浓度分别高达10、19和28 ng m ^-3。富集因子分析表明，地壳物质主导了大多数元素的丰度，而人为活动也导致了诸如Sb，Se和Pb元素的丰度。结果证实，TXRF是用于微量金属分析微克范围以及云滴中的颗粒物的有用的互补敏感技术。