Pazos-Capeáns P, Barciela-Alonso M C, Bermejo-Barrera A, Bermejo-Barrera P
Departments of Analytical Chemistry, Nutrition and Bromatology, University of Santiago de Compostela, E-15782, Santiago de Compostela, Spain.
Talanta. 2005 Feb 15;65(3):678-85. doi: 10.1016/j.talanta.2004.07.031.
In a research of chromium availability, the three-stage sequential extraction procedure, proposed by European Community Bureau of Reference (BCR), has been applied for the metal fractionation in marine sediment samples. The procedure has been modified, evaluating the effect of microwave energy to perform the sequential method. Results achieved a substantial reduction in time in comparison to the traditional shaking technique. The time of the first and the second extractions were reduced to 30s in both steps using microwave heating and working at 66W of power. To the third extraction, higher power was necessary so it was chosen to work at 198W. In the last step investigated, time was reduced to 1min, being a great improvement respect to the conventional BCR sequential extraction protocol. Chromium determinations in these extracts were carried out by Electrothermal Atomic Absorption Spectrometry (ETAAS). The developed method was applied for chromium determination in marine sediment samples from Ria de Arousa (Galicia, NW of Spain). The values obtained by our laboratory ranged from 0.10 to 1.02mugg(-1) for soluble and reducible fractions, and from 5.5 to 60.0mugg(-1) for the oxidisable fraction. The higher concentrations obtained were the chromium associated with the organic fraction of the marine sediments.
在一项铬有效性的研究中，欧洲共同体标准局（BCR）提出的三阶段连续萃取程序已应用于海洋沉积物样品中的金属分级。该程序已被修改，评估了微波能量对执行连续方法的影响。与传统的振荡技术相比，结果实现了时间的大幅减少。使用微波加热并以66W的功率工作时，第一步和第二步萃取的时间在两个步骤中均减少到30秒。对于第三步萃取，需要更高的功率，因此选择以198W工作。在研究的最后一步中，时间减少到1分钟，相对于传统的BCR连续萃取方案有了很大的改进。这些提取物中的铬测定通过电热原子吸收光谱法（ETAAS）进行。所开发的方法应用于来自里亚德阿罗萨（西班牙西北部加利西亚）的海洋沉积物样品中的铬测定。我们实验室获得的值对于可溶和可还原部分为0.10至1.02μg g⁻¹，对于可氧化部分为5.5至60.0μg g⁻¹。获得的较高浓度是与海洋沉积物有机部分相关的铬。
