Coordenação de Análises Minerais, Centro de Tecnologia Mineral-CETEM, Av. Pedro Calmon 900, Cidade Universitária, CEP 21941-908, Rio de Janeiro, RJ, Brazil.
Anal Chim Acta. 2010 Feb 5;659(1-2):55-9. doi: 10.1016/j.aca.2009.11.055. Epub 2009 Dec 2.
A method for determination of Co, Cr, Cu, Fe, Mn, Ni, Ti, V and Zn in coal fly ash samples using ultrasound-assisted digestion followed by inductively coupled plasma optical emission spectrometry (ICP-OES) is proposed. The digestion procedure consisted in the sonication of the previously dried sample with hydrofluoric acid and aqua regia at 80 degrees C for 30 min, elimination of fluorides by heating until dryness for about 1h and dissolution of the residue with nitric acid solution. A classical digestion method, used as comparative method, consisted in the addition of HCl, HNO(3) and HF to 1 g of sample, and heating on a hot plate until dryness for about 6h. The proposed method presents several advantages: it requires lower amounts of sample and reagents, and it is faster. It is also advantageous when compared to the published methods, which also use ultrasound-assisted digestion procedure: lower detection limits for Co, Cu, Ni, V and Zn, and it does not require shaking during the digestion. The detection limits (microg g(-1)) for Co, Cr, Cu, Fe, Mn, Ni, Ti, V and Zn were 0.06, 0.37, 1.0, 25, 0.93, 0.45, 4.0, 1.7 and 4.3, respectively. The results were in good agreement with those obtained by the classical method and reference values. The exception was Cr, which presented low recoveries in classical and proposed methods (83 and 87%, respectively). Also, the concentration for Cu obtained by the proposed method was significantly different from the reference value, in spite of the good recovery (91+/-1%).
本文提出了一种使用超声辅助消解结合电感耦合等离子体光学发射光谱法（ICP-OES）测定煤灰样品中 Co、Cr、Cu、Fe、Mn、Ni、Ti、V 和 Zn 的方法。消解程序包括在 80°C 下用氢氟酸和王水超声处理预先干燥的样品 30 分钟，加热至干燥约 1 小时以除去氟化物，然后用硝酸溶液溶解残渣。一种经典的消解方法（作为比较方法）包括向 1g 样品中加入 HCl、HNO3 和 HF，并在热板上加热至干燥约 6 小时。与经典方法相比，该方法具有以下优点：所需样品和试剂较少，速度较快。与其他也使用超声辅助消解程序的已发表方法相比，该方法还具有更低的 Co、Cu、Ni、V 和 Zn 检测限，且消解过程中不需要摇动。Co、Cr、Cu、Fe、Mn、Ni、Ti、V 和 Zn 的检测限（μg g-1）分别为 0.06、0.37、1.0、25、0.93、0.45、4.0、1.7 和 4.3。结果与经典方法和参考值吻合良好。除 Cr 外，经典方法和提议方法的回收率均较低（分别为 83%和 87%）。此外，尽管回收率良好（91+/-1%），但提议方法测定的 Cu 浓度与参考值显著不同。
