Institute of Soil Science and Soil Conservation, Interdisciplinary Research Centre for Biosystems, Land Use and Nutrition (IFZ), Justus Liebig University, Heinrich-Buff-Ring 26-32, D-35392 Giessen, Germany.
Talanta. 2012 Sep 15;99:594-602. doi: 10.1016/j.talanta.2012.06.042. Epub 2012 Jul 7.
Quantitative determination of metals in environmental matrices became important in the past few decades because of increasing pollutant concentrations in aquatic and terrestrial ecosystems. The extraction phase in the process of determining metals is crucial but very time-consuming. Consequently, new extraction techniques for extractable metals have been developed which probably will substitute conventional procedures in the future. The aim of this study was to improve a closed vessel microwave assisted extraction (MAE) by using EDTA as an exclusive extraction agent (MAE-EDTA) for the determination of pseudo total metal contents in solid environmental samples. For this purpose, a large set of soil and compost samples were analyzed. MAE-EDTA was compared with both closed vessel microwave assisted aqua regia extraction (MAE-AR) and a conventional aqua regia extraction (AR) method for the determination of pseudo total Cd, Cu, Mn, and Pb contents of soil and compost samples. Certified reference materials were used for comparison of recovery rates from different extraction protocols. Metal concentrations in soil and compost extracts were determined by ICP-OES. MAE-AR which was considered as a reference MAE method for further steps of the study, showed the same extraction yields in the determination of pseudo total metal contents of the investigated elements (As, Ba, Be, Cd, Co, Cr, Cu, Mn, Ni, Pb, V, Zn) in soil and compost samples as the conventional AR. MAE-EDTA gave similar values as the reference methods in the determination of Cd, Cu, and Pb amounts in soil samples and Cd, Mn, and Pb amounts in compost samples. The recovery rates ranged between 89.0-117.1% for soil samples and 93.5-104.0% for compost samples. MAE-EDTA provides fast processing of the samples that is less than one hour, including time for cooling of the samples. Apart from significantly less processing time, minimal consumption of sample and reagent chemicals is a strategic characteristic of MAE-EDTA procedure which has advantages including accuracy and reduction of contamination. The drawback of MAE-EDTA was that the optimized conditions for the metals Cd, Cu, Mn and Pb may not be generally applicable for the other metals. Therefore, the analytical parameters available in MAE-EDTA should be further investigated for the metals of interest.
在过去的几十年中，由于水生和陆地生态系统中污染物浓度的增加，环境基质中金属的定量测定变得尤为重要。在测定金属的过程中，萃取阶段是至关重要的，但非常耗时。因此，已经开发出了用于可萃取金属的新型萃取技术，这些技术可能在未来会替代传统方法。本研究的目的是改进一种封闭容器微波辅助提取（MAE），方法是使用 EDTA 作为唯一的萃取剂（MAE-EDTA），用于测定固体环境样品中的准总量金属含量。为此，分析了大量的土壤和堆肥样品。MAE-EDTA 与封闭容器微波辅助王水提取（MAE-AR）和传统王水提取（AR）方法进行了比较，以测定土壤和堆肥样品中准总量 Cd、Cu、Mn 和 Pb 的含量。使用认证参考材料比较了不同提取方案的回收率。通过 ICP-OES 测定土壤和堆肥提取物中的金属浓度。MAE-AR 被认为是本研究进一步步骤的参考 MAE 方法，在测定土壤和堆肥样品中研究元素（As、Ba、Be、Cd、Co、Cr、Cu、Mn、Ni、Pb、V、Zn）的准总量金属含量时，其萃取产率与传统 AR 相同。MAE-EDTA 法在测定土壤样品中的 Cd、Cu 和 Pb 量以及堆肥样品中的 Cd、Mn 和 Pb 量方面，与参考方法给出了相似的值。回收率范围为 89.0-117.1%，适用于土壤样品，93.5-104.0%，适用于堆肥样品。MAE-EDTA 提供了快速的样品处理，包括样品冷却时间在内，不到一个小时。除了处理时间明显缩短外，最小的样品和试剂化学品消耗是 MAE-EDTA 方法的战略特征，该方法具有准确性和减少污染的优点。MAE-EDTA 的缺点是优化的 Cd、Cu、Mn 和 Pb 等金属条件可能不适用于其他金属。因此，需要进一步研究 MAE-EDTA 中可用的分析参数，以了解感兴趣的金属。
