Title
A new approach combining analytical methods for workplace exposure assessment of inhalable multi-walled carbon nanotubes
Author
Tromp, P.C.
Kuijpers, E.
Bekker, C.
Godderis, L.
Lan, Q.
Jedynska, A.D.
Vermeulen, R.
Pronk, A.
Publication year
2017
Abstract
To date there is no consensus about the most appropriate analytical method for measuring carbon nanotubes (CNTs), hampering the assessment and limiting the comparison of data. The goal of this study is to develop an approach for the assessment of the level and nature of inhalable multi-wall CNTs (MWCNTs) in an actual workplace setting by optimizing and evaluating existing analytical methods. In a company commercially producing MWCNTs, personal breathing zone samples were collected for the inhalable size fraction with IOM samplers; which were analyzed with carbon analysis, inductively coupled plasma mass spectrometry (ICP-MS) and scanning electron microscopy/ energy dispersive X-ray spectroscopy (SEM/EDX). Analytical methods were optimized for carbon analysis and SEM/EDX. More specifically, methods were applied and evaluated for background correction using carbon analyses and SEM/EDX, CNT structure count with SEM/EDX and subsequent mass conversion based on both carbon analyses and SEM/EDX. A moderate-to-high concordance correlation coefficient (RC) between carbon analyses and SEM/EDX was observed [RC = 0.81, 95% confidence interval (CI): 0.59-0.92] with an absolute mean difference of 59 ug m-3. A low RC between carbon analyses and ICP-MS (RC = 0.41, 95% CI: 0.07-0.67) with an absolute mean difference of 570 ug m-3 was observed. The large absolute difference between EC and metals is due to the presence of non-embedded inhalable catalyst particles, as a result of which MWCNT concentrations were over- estimated. Combining carbon analysis and SEM/EDX is the most suitable for quantitative exposure assessment of MWCNTs in an actual workplace situation. © The Author 2017. Published by Oxford University Press on behalf of the British Occupational Hygiene Society.
Subject
Urban Mobility & Environment
Urbanisation
Environment & Sustainability
Scanning electron microscopy
Carbon nanotubes
Electron microscopy
Energy dispersive spectroscopy
Inductively coupled plasma mass spectrometry
Mass spectrometers
Mass spectrometry
Nanotubes
Scanning electron microscopy
X ray spectroscopy
Yarn
Background correction
Carbon analysis
Confidence interval
Correlation coefficient
Energy dispersive X ray spectroscopy
Exposure assessment
ICP-MS
Inductively coupled plasma mass spectrometries (ICPMS)
Multiwalled carbon nanotubes (MWCN)
EMS - Environmental Modelling, Sensing & Analysis
To reference this document use:
http://resolver.tudelft.nl/uuid:2d38e851-d10d-436b-9917-1c43452d4398
DOI
https://doi.org/10.1093/annweh/wxx053
TNO identifier
782415
ISSN
2398-7308
Source
Annals of Work Exposures and Health, 61 (61), 759-772
Document type
article