Avramescu Mary-Luyza, Rasmussen Pat E, Chénier Marc
Environmental Health Science and Research Bureau, HECSB, Health Canada, 50 Columbine Driveway, Tunney's Pasture 0803C, Ottawa, ON, Canada K1A 0K9.
Environmental Health Science and Research Bureau, HECSB, Health Canada, 50 Columbine Driveway, Tunney's Pasture 0803C, Ottawa, ON, Canada K1A 0K9; Department of Earth and Environmental Sciences, University of Ottawa, Ottawa, ON, Canada K1N 6N5.
J Anal Methods Chem. 2016;2016:3834292. doi: 10.1155/2016/3834292. Epub 2016 Nov 16.
Residual metal impurities in carbon nanotubes (CNTs) provide a means to distinguish CNT from non-CNT sources of elemental carbon in environmental samples. A practical and cost-effective analytical approach is needed to support routine surface monitoring of CNT metal tracers using wipe sampling. Wipe sampling for CNT metal tracers is considered a qualitative indicator of the presence of CNTs, not a quantitative exposure metric. In this study, two digestion approaches (microwave-assisted nitric acid/HO digestion and ultrasonic nitric/HF acid digestion) in conjunction with Inductively Coupled Plasma Mass Spectrometry (ICP-MS) determination were evaluated for their ability to extract metal impurities from CNT particles captured on wipe substrates. Aliquots of different carbon nanotubes (including NIST 2483 single-wall CNT) with and without GhostWipes™ (ASTM E-1792 compliant) were used to compare the performance of the digestion methods. The microwave digestion method accommodated the bulky wipe sample and also eliminated potential ICP-MS signal interferences related to incomplete digestion. Although quantitative recoveries requiring lengthy multistep digestion protocols may be necessary in other applications, the near-total recoveries achieved in the present study for CNT catalyst elements were adequate for identifying surface contamination of CNTs in the workplace using wipe sampling.
碳纳米管（CNT）中的残留金属杂质提供了一种区分环境样品中碳纳米管与非碳纳米管元素碳来源的方法。需要一种实用且经济高效的分析方法来支持使用擦拭采样对碳纳米管金属示踪剂进行常规表面监测。对碳纳米管金属示踪剂进行擦拭采样被认为是碳纳米管存在的定性指标，而非定量暴露指标。在本研究中，评估了两种消解方法（微波辅助硝酸/过氧化氢消解和超声硝酸/氢氟酸消解）结合电感耦合等离子体质谱（ICP-MS）测定从捕获在擦拭基质上的碳纳米管颗粒中提取金属杂质的能力。使用含有和不含GhostWipes™（符合ASTM E-1792标准）的不同碳纳米管（包括NIST 2483单壁碳纳米管）的等分试样来比较消解方法的性能。微波消解方法适用于体积较大的擦拭样品，还消除了与不完全消解相关的潜在ICP-MS信号干扰。虽然在其他应用中可能需要采用冗长的多步消解方案才能实现定量回收率，但本研究中对碳纳米管催化剂元素实现的近乎完全回收率足以通过擦拭采样识别工作场所中碳纳米管的表面污染情况。
