Ciências Tecnológicas, Centro Universitário Franciscano-UNIFRA, Rua dos Andradas, 1614, Santa Maria/RS, Brazil.
Anal Chem. 2010 May 15;82(10):4298-303. doi: 10.1021/ac100429v.
A procedure based on microwave-induced combustion (MIC) was applied for carbon nanotube (CNT) digestion and further determination of La and Ni by inductively coupled plasma optical emission spectrometry (ICP OES). Samples (up to 400 mg) were completely combusted at 20 bar of oxygen, and a reflux step was applied to improve the analyte absorption. Combustion was finished in less than 50 s, and analytes were absorbed in diluted acid solution. Absorbing solutions ranging from 1 to 12 mol L(-1) for HCl and from 1 to 14 mol L(-1) HNO(3) were tested. Accuracy for both analytes was evaluated using certified reference materials and analyte spikes. Neutron activation analysis was also used to check accuracy for La. Agreement was better than 96% for La and Ni using a 4 mol L(-1) absorbing solution of HNO(3) or HCl and 15 min of reflux. The residual carbon content was lower than 0.5%. Up to eight samples could be digested simultaneously in 36 min, that makes the throughput using MIC more suitable when it is compared to the digestion by dry ashing as recommended by other procedures. The obtained limits of detection using MIC were lower than those using dry ashing, and a single absorbing solution, e.g., diluted HNO(3), can be used for simultaneous determination of La and Ni by ICP OES.
采用基于微波诱导燃烧（MIC）的程序对碳纳米管（CNT）进行消解，并通过电感耦合等离子体光学发射光谱法（ICP-OES）进一步测定镧和镍。样品（高达 400mg）在 20 巴氧气下完全燃烧，应用回流步骤来提高分析物的吸收率。燃烧在不到 50 秒内完成，分析物被吸收在稀释的酸溶液中。测试了范围为 1 至 12mol/L 的 HCl 和 1 至 14mol/L 的 HNO3 吸收溶液。使用标准参考物质和分析物加标来评估两种分析物的准确性。还使用中子活化分析来检查镧的准确性。使用 4mol/L 的 HNO3 或 HCl 吸收溶液和 15 分钟回流，对于镧和镍的准确性均优于 96%。残余碳含量低于 0.5%。在 36 分钟内可以同时消解多达 8 个样品，这使得与其他程序推荐的干法灰化消解相比，MIC 的高通量更具优势。使用 MIC 获得的检测限低于干法灰化消解，并且可以使用单一的吸收溶液（例如，稀释的 HNO3）通过 ICP-OES 同时测定镧和镍。
