Sampling Techniques on Collecting Fine Carbon Nanotube Fibers for Exposure Assessment

• Published in: Scientific reports 2019-05, Vol.9 (1), p.7137, Article 7137
• Main Authors: Khattak, Jared, Theisen, Daniel, Tsai, Candace S. J.
• Format: Article
• Language: English
• Subjects: 692/1537; 704/172/4081; Air Pollutants - analysis; Carbon Fiber - analysis; Environmental Monitoring - instrumentation; Fibers; Humanities and Social Sciences; Microscopy, Electron, Transmission; multidisciplinary; Nanotubes, Carbon - chemistry; Particle Size; Sampling; Sampling techniques; Science; Science (multidisciplinary)
• ISSN: 2045-2322; 2045-2322
• DOI: 10.1038/s41598-019-43661-1

Carbon nanotube (CNT) sampling using an open-faced 25 mm cassette fiber sampling method and a newly developed direct sampling device was evaluated for the size fractioned analysis of collected airborne CNT fibers to improve the sampling and analytical methods. The open-faced 25 mm cassette fiber sampling method primarily collected large agglomerates, with the majority of collected particles being larger than two micrometer in size. Most of CNT structures collected by the new direct sampling device were individual fibers and clusters smaller than one micrometer with a high particle number concentration discrepancy compared to the open-faced 25 mm cassette method raising the concern of this sampling method to representatively characterize the respirable size fraction of CNT aerosols. This work demonstrates that a specialized technique is needed for collecting small fibers to provide a more representative estimate of exposure. It is recommended that an additional sampler be used to directly collect and analyze small fibers in addition to the widely accepted sampling method which utilizes an open-faced 25 mm cassette.