Dean John Richard
Biomolecular and Biomedical Research Centre, School of Applied Sciences, Northumbria University, Newcastle upon Tyne, UK.
Methods Mol Biol. 2010;599:15-36. doi: 10.1007/978-1-60761-439-5_2.
This chapter considers the use of a variety of approaches to assess either the bioavailability or the bioaccessibility of metals in soil. The bioavailability of metals from soils is considered with respect to a series of single-extraction methods, including the use of ethylenediaminetetraacetic acid (EDTA), acetic acid, diethylenetriaminepentaacetic acid (DTPA), ammonium nitrate, calcium chloride and sodium nitrate. Then, a procedure for the recovery of metals using a three-stage sequential extraction protocol is described. Two alternate approaches for assessing the environmental health risk to humans by undertaking in vitro gastrointestinal extraction (also known as the physiologically based extraction test, PBET) are considered. Finally, two acid digestion protocols that allow the pseudo-total metal content of samples to be assessed are provided. In all cases details of how the different approaches can be performed are provided, including the specific reagents required (and their preparation), details of the different extraction and acid digestion protocols to be followed and suitable analytical details to allow the measurement of metals by inductively coupled plasma mass spectrometry (ICP-MS) with/without a collision/reaction cell. A detailed Notes section provides experimental details to guide the reader through some of the practical aspects of the procedures. Finally, some experimental results are provided as evidence of the suitability of the approaches described including single-extraction data, using EDTA and acetic acid, for metals in CRM BCR 700. In addition, in vitro gastrointestinal extraction data are provided for metals in CRM SRM 1570A (spinach leaves). The influence of time on the intestinal fluid phase on the recovery of metals in CRM SRM 1570A (spinach leaves) and CRM INCT-TL-1 (tea leaves) is investigated, as well as the repeatability in terms of recovery of metals from soil over a 3-week period by in vitro gastrointestinal extraction.
本章探讨了使用多种方法来评估土壤中金属的生物有效性或生物可及性。从土壤中获取金属的生物有效性是通过一系列单一萃取方法来考量的，包括使用乙二胺四乙酸（EDTA）、乙酸、二乙烯三胺五乙酸（DTPA）、硝酸铵、氯化钙和硝酸钠。接着，描述了一种使用三阶段连续萃取方案回收金属的程序。还考虑了通过体外胃肠道萃取（也称为基于生理学的萃取试验，PBET）来评估对人类的环境健康风险的两种替代方法。最后，提供了两种能够评估样品中准总金属含量的酸消解方案。在所有情况下，都给出了如何执行不同方法的详细信息，包括所需的特定试剂（及其制备方法）、要遵循的不同萃取和酸消解方案的详细信息，以及适合通过带/不带碰撞/反应池的电感耦合等离子体质谱（ICP-MS）测量金属的分析细节。一个详细的“注释”部分提供了实验细节，以指导读者了解这些程序的一些实际操作方面。最后，给出了一些实验结果，作为所描述方法适用性的证据，包括使用EDTA和乙酸对CRM BCR 700中金属的单一萃取数据。此外，还提供了CRM SRM 1570A（菠菜叶）中金属的体外胃肠道萃取数据。研究了时间对CRM SRM 1570A（菠菜叶）和CRM INCT-TL-1（茶叶）中肠道液相中金属回收率的影响，以及通过体外胃肠道萃取在3周时间内从土壤中回收金属的重复性。
