Canepari S, Cardarelli E, Giuliano A, Pietrodangelo A
Chemistry Department, University of Rome "La Sapienza", P.le Aldo Moro, 5, 00185 Rome, Italy.
Talanta. 2006 May 15;69(3):581-7. doi: 10.1016/j.talanta.2005.10.023. Epub 2005 Nov 28.
The optimisation of a micro-analytical two-step sequential leaching procedure for the determination of non-volatile ions (NO(3)(-), SO(4)(2-), Cl(-), Na(+), Mg(2+), NH(4)(+) and Ca(2+)) and of 17 elements (Al, As, Cd, Cr, Cu, Fe, Mg, Mn, Ni, Pb, S, Se, V, Zn, Sb, Si and Ti) in two fractions-extract and residue-on the same sample of air particulate matter is described. The two-step method was tested on the SRM NIST 1648 for equivalence with two reference methods, the EMEP procedure for ions extraction and the EN 12341 standard for the elemental determination of the PM(10) and is suitable for application to small sample amounts (less than 1mg of particulate matter is needed), i.e. those collected by daily low volume filter-sampling. Performance times of the procedure were optimised to meet the target of routine application for large scale monitoring samples. A single ultrasonic-assisted extraction of air particulate matter is performed in 0.01M acetate buffer at pH 4.5, followed by IC ions analysis and ICP-OES elemental analysis of the extract and by ICP-OES elemental analysis of the mineralized residue after dissolution by microwave-assisted digestion with a HNO(3)/H(2)O(2) mixture. Using a pH buffered extracting solvent was preferred to water or diluted acid solutions to improve the reproducibility of metals extraction with respect to existing leaching methods; the influence of pH, nature and concentration of the buffer solution and extraction time on analytes concentration in the extract is discussed. Values of ions extraction and elements recoveries resulted fairly equivalent with those obtained by the reference methods. The study was also extended to some non-certified elements (Mg, S, Sb, Si and Ti) for their environmental significance. Elements recoveries were obtained as sum of the extract and residue fractions and were comparable with those obtained by direct dissolution. Standard deviations were within 10% for almost all detected ions and elements.
描述了一种用于测定空气颗粒物同一样品中两个部分（提取物和残渣）的非挥发性离子（NO₃⁻、SO₄²⁻、Cl⁻、Na⁺、Mg²⁺、NH₄⁺和Ca²⁺）以及17种元素（Al、As、Cd、Cr、Cu、Fe、Mg、Mn、Ni、Pb、S、Se、V、Zn、Sb、Si和Ti）的微分析两步连续浸出程序的优化方法。该两步法在SRM NIST 1648上进行了测试，以与两种参考方法等效，一种是用于离子提取的EMEP程序，另一种是用于PM₁₀元素测定的EN 12341标准，并且适用于少量样品（所需颗粒物少于1mg），即通过每日低流量过滤采样收集的样品。优化了该程序的执行时间，以满足大规模监测样品常规应用的目标。在pH为4.5的0.01M乙酸盐缓冲液中对空气颗粒物进行单次超声辅助提取，随后对提取物进行离子色谱离子分析和电感耦合等离子体发射光谱元素分析，并对用HNO₃/H₂O₂混合物微波辅助消解溶解后的矿化残渣进行电感耦合等离子体发射光谱元素分析。与水或稀酸溶液相比，使用pH缓冲提取溶剂更有利于提高金属提取的重现性，相对于现有的浸出方法；讨论了pH、缓冲溶液的性质和浓度以及提取时间对提取物中分析物浓度的影响。离子提取值和元素回收率与参考方法获得的值相当。该研究还扩展到了一些未经认证的元素（Mg、S、Sb、Si和Ti），考虑到它们的环境意义。元素回收率以提取物和残渣部分的总和获得，并且与直接溶解获得的回收率相当。几乎所有检测到的离子和元素的标准偏差都在10%以内。
