Institute for National Measurement Standards, National Research Council of Canada, Ottawa, ON, Canada.
Anal Bioanal Chem. 2012 Jan;402(1):429-38. doi: 10.1007/s00216-011-5509-y. Epub 2011 Nov 29.
Several techniques were evaluated for the establishment of reliable water/moisture content of single-wall carbon nanotubes. Karl Fischer titration (KF) provides a direct measure of the water content and was used for benchmarking against results obtained by conventional oven drying, desiccation over anhydrous magnesium perchlorate as well as by thermogravimetry and prompt gamma-ray activation analysis. Agreement amongst results was satisfactory with the exception of thermogravimetry, although care must be taken with oven drying as it is possible to register mass gain after an initial moisture loss if prolonged drying time or elevated temperatures (120 °C) are used. Thermogravimetric data were precise but a bias was evident that could be accounted for by considering the non-selective loss of mass as volatile carbonaceous components. Simple drying over anhydrous magnesium perchlorate for a minimum period of 8-10 days is recommended if KF is not available for this measurement.
几种技术被评估用于建立单壁碳纳米管的可靠水分含量。卡尔费休滴定（KF）提供了水分含量的直接测量值，并与常规烘箱干燥、无水高氯酸镁干燥以及热重分析和瞬发伽马射线激活分析的结果进行了基准测试。除了热重分析之外，结果之间的一致性令人满意，尽管在使用烘箱干燥时需要小心，因为如果使用延长的干燥时间或升高的温度（120°C），在初始水分损失后可能会记录到质量增加。热重分析数据很精确，但存在明显的偏差，可以通过考虑非选择性的挥发性碳质成分的质量损失来解释。如果无法进行 KF 测量，则建议在无水高氯酸镁上进行简单干燥，干燥时间至少为 8-10 天。
