Laboratoire de Chimie Analytique BioInorganique et Environnement, UMR IPREM 5254 UPPA/CNRS-Technopôle Hélioparc, Université de Pau et des Pays de l'Adour (UPPA), Pau cedex, France.
Anal Bioanal Chem. 2011 Dec;401(10):3345-53. doi: 10.1007/s00216-011-5413-5. Epub 2011 Sep 27.
In this work, the potentiality of asymmetrical flow field-flow fractionation (A4F) hyphenated to UV detector and multi-angle light scattering (MALS) was investigated for accurately determining multi-walled carbon nanotube (MWCNT) length and its corresponding dispersion state in aqueous medium. Fractionation key parameters were studied to obtain a method robust enough for heterogeneous sample characterization. The main A4F conditions were 10(-5) mL min(-1) NH(4)NO(3), elution flow of 1 mL min(-1), and cross flow of 2 mL min(-1). The recovery was found to be (94 ± 2)%. Online MALS analysis of eluted MWCNT suspension was performed to obtain length distribution. The length measurements were performed with a 4% relative standard deviation, and the length values were shown to be in accordance with expected ones. The capabilities of A4F-UV-MALS to size characterize various MWCNT samples and differentiate them according to their manufacturing process were evaluated by monitoring ball-milled MWCNT and MWCNT dispersions. The corresponding length distributions were found to be over 150-650 and 150-1,156 nm, respectively. A4F-UV-MALS was also used to evaluate MWCNT dispersion state in aqueous medium according to the surfactant concentration and sonication energy involved in the preparation of the dispersions. More especially, the presence or absence of aggregates, number and size of different populations, as well as size distributions were determined. A sodium dodecyl sulfate concentration of 15 to 30 mmol L(-1) and a sonication energy ranged over 20-30 kJ allow obtaining an optimal MWCNT dispersion. It is especially valuable for studying nanomaterials and checking their manufacturing processes, size characterization being always of high importance.
在这项工作中，研究了不对称流场流分离（A4F）与紫外检测器和多角度光散射（MALS）联用的可能性，以准确确定多壁碳纳米管（MWCNT）在水介质中的长度及其相应的分散状态。研究了分馏关键参数，以获得一种足够稳健的方法来对异质样品进行特征描述。主要的 A4F 条件是 10(-5) mL min(-1) NH(4)NO(3)、洗脱流速为 1 mL min(-1)和交叉流速为 2 mL min(-1)。回收率为（94 ± 2）%。在线洗脱 MWCNT 悬浮液的 MALS 分析用于获得长度分布。长度测量的相对标准偏差为 4%，并且长度值与预期值一致。通过监测球磨 MWCNT 和 MWCNT 分散体，评估了 A4F-UV-MALS 对各种 MWCNT 样品进行尺寸表征并根据其制造工艺对其进行区分的能力。相应的长度分布分别为 150-650nm 和 150-1,156nm。还根据制备分散体中涉及的表面活性剂浓度和超声能量，使用 A4F-UV-MALS 来评估 MWCNT 在水介质中的分散状态。更特别地，确定了团聚体的存在与否、不同群体的数量和大小以及尺寸分布。15 至 30mmol L(-1)的十二烷基硫酸钠浓度和 20 至 30kJ 的超声能量范围允许获得最佳的 MWCNT 分散体。这对于研究纳米材料和检查其制造工艺特别有价值，因为尺寸特征化始终非常重要。
