Environ Sci Process Impacts. 2013 Jan;15(1):204-13. doi: 10.1039/c2em30717k.
Detection of single walled carbon nanotubes (CNTs) was performed using single particle-inductively coupled plasma-mass spectrometry (spICPMS). Due to the ambiguities inherent in detecting CNTs by carbon analysis, particularly in complex environmental matrices, this study focuses on using trace catalytic metals intercalated in the CNT structure as proxies for the nanotubes. Using a suite of commercially available CNTs, the monoisotopic elements Co and Y were found to be the most effective for differentiation of particulate pulses from background. The small, variable, amount of trace metal in each CNT makes separation from instrumental background challenging; multiple cut-offs for determining CNT number concentration were investigated to maximize the number of CNTs detected and minimize the number of false positives in the blanks. In simple solutions the number of CNT pulses detected increased linearly with concentration in the ng L−1 range. However, analysis of split samples by both spICPMS and Nanoparticle Tracking Analysis (NTA) showed the quantification of particle number concentration by spICPMS to be several orders of magnitude lower than by NTA. We postulate that this is a consequence of metal content and/or size, caused by the presence of many CNTs that do not contain enough metal to be above the instrument detection limit, resulting in undercounting CNTs by spICPMS. However, since the detection of CNTs at low ng L−1 concentrations is not possible by other techniques, spICPMS is still a more sensitive technique for detecting the presence of CNTs in environmental, materials, or biological applications. To highlight the potential of spICPMS in environmental studies the release of CNTs from polymer nanocomposites into solution was monitored, showcasing the technique's ability to detect changes in released CNT concentrations as a function of CNT loading.
使用单颗粒电感耦合等离子体质谱（spICPMS）检测单壁碳纳米管（CNTs）。由于通过碳分析检测 CNTs 存在固有模糊性，特别是在复杂的环境基质中，因此本研究侧重于使用嵌入 CNT 结构中的痕量催化金属作为纳米管的示踪剂。使用一系列市售 CNT，发现同位素元素 Co 和 Y 最有效，可将颗粒脉冲与背景区分开来。每个 CNT 中痕量金属的数量小且变化不定，因此难以与仪器背景分离；研究了多种确定 CNT 数浓度的截止值，以最大限度地增加检测到的 CNT 数量，并最大限度地减少空白中的假阳性数量。在简单的溶液中，随着 ng L−1 范围内浓度的增加，检测到的 CNT 脉冲数量呈线性增加。然而，通过 spICPMS 和纳米颗粒跟踪分析（NTA）对拆分样品的分析表明，spICPMS 对颗粒数浓度的定量比 NTA 低几个数量级。我们假设这是由于金属含量和/或尺寸造成的，这是由于存在许多 CNT 它们不含有足够的金属以超过仪器检测限，导致 spICPMS 对 CNT 的计数不足。然而，由于其他技术无法在低 ng L−1 浓度下检测 CNT，因此 spICPMS 仍然是检测环境、材料或生物应用中 CNT 存在的更敏感技术。为了突出 spICPMS 在环境研究中的潜力，监测了聚合物纳米复合材料中 CNT 向溶液中的释放情况，展示了该技术检测 CNT 释放浓度随 CNT 负载变化的能力。
