Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, University of Santiago de Compostela, Avenida das Ciencias, s/n. 15782, Santiago de Compostela, Spain.
Talanta. 2011 Jan 15;83(3):840-9. doi: 10.1016/j.talanta.2010.10.035. Epub 2010 Nov 2.
The BCR (the Community Bureau of Reference) of the European Union sequential extraction scheme for metal partitioning in estuarine sediments has been accelerated by using a matrix solid phase dispersion (MSPD) approach. The MSPD assisted BCR procedure consists of passing the extractants proposed by conventional BCR protocol (0.11 M acetic acid, 0.1M hydroxylammonium chloride and 8.8M hydrogen peroxide plus 1M ammonium acetate) through the dispersed sample packaged inside a disposable syringe. Different silica-, magnesium- and aluminium-based materials were tested as dispersing agents and sea sand was found to offer the best performances. Variables for assisting the three stages of the BCR protocol were optimized, and accurate results were obtained when assisting the first and the third stages (exchangeable and oxidizable fractions, respectively). However, lack of accuracy was observed when assisting the second step (reducible fraction) and this result agrees with most of the assisted BCR procedures for which extracting the reducible fraction is the most troublesome stage. The organic matter oxidation (third stage) was successfully assisted by passing hydrogen peroxide at 50°C through the dispersed sample inside de syringe just before passing ammonium acetate. Therefore, the time-consuming and unsafe conventional organic matter oxidation processes, commonly performed even for microwave/ultrasounds assisted BCR procedures, are totally avoided. Inductively coupled plasma-mass spectrometry (ICP-MS) was used as a selective detector. The target elements were Cd, Co, Cr, Mn, Ni, Sr and Zn (first stage), Cd, Co and Ni (second stage), and Co, Cr, Mn, Ni, Sr and Zn (third stage). Repeatability of the method (n=7) was good, and RSDs values of 9, 10, 10, 8, 8, 3 and 8% was obtained for Cd, Co, Cr, Mn, Ni, Sr and Zn, respectively (first stage); 10, 9 and 9% for Cd, Co and Ni, respectively (second stage); and 6, 2, 3, 4, 7 and 9% Co, Cr, Mn, Ni, Sr and Zn, respectively (third stage). The procedure was also validated by analysing two certified reference materials (CRM 601 and CRM 701). Good accuracy was obtained for the target elements extracted at the first stage: Cd (4.0 ± 0.1 and 7.3 ± 0.09 μg g(-1) in CRM 601 and CRM 701, respectively), Cr (0.36 ± 0.008 and 2.21 ± 0.08 μg g(-1) in CRM 601 and CRM 701, respectively), Ni (8.0 ± 0.3 and 15.4 ± 0.3 μg g(-1) in CRM 601 and CRM 701, respectively) and Zn (262 ± 3 and 203 ± 3 μg g(-1) in CRM 601 and CRM 701, respectively). Also, good accuracy was observed for elements extracted at the third step: Cd (1.8 ± 0.09 and 0.29 ± 0.03 μg g(-1) in CRM 601 and CRM 701, respectively), Cr (145 ± 4 μg g(-1) in CRM 701), Ni (8.2 ± 0.7 and 15.1 ± 0.5 μg g(-1) in CRM 601 and CRM 701, respectively) and Zn (45 ± 0.7 μg g(-1) in CRM 701).
欧盟社区局（BCR）的金属在河口沉积物中的序列提取方案已通过使用基质固相分散（MSPD）方法进行了加速。MSPD 辅助的 BCR 程序包括通过分散在一次性注射器内的样品通过传统 BCR 方案（0.11 M 乙酸、0.1 M 羟氨盐酸盐和 8.8 M 过氧化氢加 1 M 乙酸铵）提出的提取剂。不同的硅胶、镁和铝基材料被测试作为分散剂，发现海砂提供了最佳性能。协助 BCR 协议三个阶段的变量进行了优化，并在协助第一和第三阶段（分别为可交换和可氧化部分）时获得了准确的结果。然而，在协助第二步（可还原部分）时观察到准确性不足，这一结果与大多数辅助 BCR 程序一致，其中提取可还原部分是最麻烦的阶段。通过在注射器内分散样品中通过 50°C 的过氧化氢来成功协助有机物质氧化（第三阶段），然后再通过铵乙酸。因此，避免了繁琐且不安全的传统有机物质氧化过程，即使对于微波/超声波辅助 BCR 程序也通常需要进行这些过程。电感耦合等离子体质谱（ICP-MS）被用作选择性检测器。目标元素是 Cd、Co、Cr、Mn、Ni、Sr 和 Zn（第一阶段）、Cd、Co 和 Ni（第二阶段）和 Co、Cr、Mn、Ni、Sr 和 Zn（第三阶段）。该方法的重复性良好，Cd、Co、Cr、Mn、Ni、Sr 和 Zn 的 RSD 值分别为 9%、10%、10%、8%、8%、3%和 8%（第一阶段）；Cd、Co 和 Ni 的 RSD 值分别为 10%、9%和 9%（第二阶段）；Co、Cr、Mn、Ni、Sr 和 Zn 的 RSD 值分别为 6%、2%、3%、4%、7%和 9%（第三阶段）。该程序还通过分析两个认证参考材料（CRM 601 和 CRM 701）进行了验证。在第一阶段提取的目标元素获得了良好的准确性：Cd（CRM 601 和 CRM 701 中的 4.0 ± 0.1 和 7.3 ± 0.09 μg g(-1)）、Cr（CRM 601 和 CRM 701 中的 0.36 ± 0.008 和 2.21 ± 0.08 μg g(-1)）、Ni（CRM 601 和 CRM 701 中的 8.0 ± 0.3 和 15.4 ± 0.3 μg g(-1)）和 Zn（CRM 601 和 CRM 701 中的 262 ± 3 和 203 ± 3 μg g(-1)）。此外，在第三阶段提取的元素也观察到了良好的准确性：Cd（CRM 601 和 CRM 701 中的 1.8 ± 0.09 和 0.29 ± 0.03 μg g(-1)）、Cr（CRM 701 中的 145 ± 4 μg g(-1)）、Ni（CRM 601 和 CRM 701 中的 8.2 ± 0.7 和 15.1 ± 0.5 μg g(-1)）和 Zn（CRM 701 中的 45 ± 0.7 μg g(-1)）。
