A suitable protocol for the collection, extraction, and characterization of a large quantity of a local and current fine particulate matter (PM_2.5) was developed, to provide homogeneous PM_2.5 amounts for use in in vitro and in vivo toxicological assays rather than a generic and obsolete standard reference material (SRM). PM_2.5 samples were collected at an outdoor urban background site in Como, Northern Italy, using a high-volume air sampler (500 L/min) equipped with polytetrafluoroethylene (PTFE)-coated glass fiber filters (eight sampling campaigns of 24–96 h each, from February to April 2019). PM_2.5 was extracted from the filters by sequential sonication steps and the final pooled extract was filtered to remove the glass fibers released during extraction. Several PM_2.5 aliquots (n = 55) were then prepared from the PM_2.5 dry residue for i) a chemical characterization of the elements, inorganic ions, and the carbonaceous fraction and ii) in vivo and in vitro studies. The proposed protocol allowed a large amount of ambient PM_2.5 (>300 mg) to be collected within a reasonably short time. An average extraction efficiency of 75% was achieved, and the chemical analyses conducted on a set of PM_2.5-replicates revealed a satisfactory level of precision, ranging from 3% (anions and OC) to 10% (trace metals and EC), thereby confirming the possibility of obtaining aliquots with homogeneous mass and composition. Finally, the emerging differences with the SRM 1648a elemental composition suggest the importance of location- and time-specific particulate testing, which is truly representative of the actual exposure scenario for specific populations.

开发了用于收集、提取和表征大量局部和当前细颗粒物 (PM _2.5 )的合适方案，以提供均匀的 PM _2.5量，用于体外和体内毒理学分析，而不是通用和过时的标准参考材料 (SRM)。PM _2.5样本是在意大利北部科莫的一个室外城市背景地点收集的，使用配备聚四氟乙烯 (PTFE) 涂层玻璃纤维过滤器的大容量空气采样器 (500 L/min)（八次采样活动，24-96 小时）每个，从 2019 年 2 月到 4 月）。下午_2.5通过连续的超声处理步骤从过滤器中提取出 ，并过滤最终合并的提取物以去除提取过程中释放的玻璃纤维。然后从 PM _2.5干残留物中制备几个 PM _2.5等分试样（n = 55），用于 i) 元素、无机离子和含碳部分的化学表征以及 ii)体内和体外研究。提议的协议允许在合理的短时间内收集大量环境 PM _2.5 (>300 mg)。实现了 75% 的平均提取效率，并对一组 PM _2.5进行了化学分析- 重复显示了令人满意的精度水平，范围从 3%（阴离子和 OC）到 10%（痕量金属和 EC），从而证实了获得具有均匀质量和组成的等分试样的可能性。最后，SRM 1648a 元素组成的新差异表明了特定位置和特定时间的颗粒物测试的重要性，它真正代表了特定人群的实际暴露情况。