Environmental Health Science and Research Bureau, HECSB, Health Canada, 50 Colombine Driveway, Tunney's Pasture 0803C, Ottawa, Ontario, Canada , K1A 0K9.
University of Ottawa , Earth and Environmental Sciences Department, Ottawa, Ontario, Canada K1N 6N5.
Environ Sci Technol. 2015 Nov 3;49(21):12888-96. doi: 10.1021/acs.est.5b02578. Epub 2015 Oct 22.
This study investigated three area sampling approaches for using metal impurities in carbon nanotubes (CNTs) to identify CNT releases in workplace environments: air concentrations (μg/m3), surface loadings (μg/cm2), and passive deposition rates (μg/m2/h). Correlations between metal impurities and CNTs were evaluated by collecting simultaneous colocated area samples for thermal-optical analysis (for CNTs) and ICP-MS analysis (for metals) in a CNT manufacturing facility. CNTs correlated strongly with Co (residual catalyst) and Ni (impurity) in floor surface loadings, and with Co in passive deposition samples. Interpretation of elemental ratios (Co/Fe) assisted in distinguishing among CNT and non-CNT sources of contamination. Stable isotopes of Pb impurities were useful for identifying aerosolized CNTs in the workplace environment of a downstream user, as CNTs from different manufacturers each had distinctive Pb isotope signatures. Pb isotopes were not useful for identifying CNT releases within a CNT manufacturing environment, however, because the CNT signature reflected the indoor background signature. CNT manufacturing companies and downstream users of CNTs will benefit from the availability of alternative and complementary strategies for identifying the presence/absence of CNTs in the workplace and for monitoring the effectiveness of control measures.
本研究调查了三种利用碳纳米管（CNT）中的金属杂质来识别工作环境中 CNT 释放的区域采样方法：空气中浓度（μg/m3）、表面负载（μg/cm2）和被动沉积速率（μg/m2/h）。通过在 CNT 制造设施中同时收集用于热光分析（用于 CNT）和 ICP-MS 分析（用于金属）的共定位区域样品，评估了金属杂质与 CNT 之间的相关性。在地板表面负载中，CNTs 与 Co（残留催化剂）和 Ni（杂质）强烈相关，与 Co 相关的是被动沉积样品。元素比（Co/Fe）的解释有助于区分 CNT 和非 CNT 污染来源。Pb 杂质的稳定同位素可用于识别下游使用者工作环境中的气溶胶化 CNT，因为不同制造商的 CNT 各自具有独特的 Pb 同位素特征。然而，Pb 同位素对于识别 CNT 制造环境中的 CNT 释放并不有用，因为 CNT 特征反映了室内背景特征。CNT 制造公司和 CNT 的下游使用者将受益于替代和补充策略的可用性，这些策略可用于识别工作场所中 CNT 的存在/不存在，并监测控制措施的有效性。
