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Particle Size Distributions for Cellulose Nanocrystals Measured by Transmission Electron Microscopy: An Interlaboratory Comparison



John E. Bonevich, Juris Meija, Bushell Michael, Martin Couillard, Kai Cui, Johan Foster, Douglas M. Fox, Markus Heidelmann, Byong Chon Park, Lingling Ren, Aleksandr B. Stefaniak, Ralf Theissmann, Natalia de Val Alda, Linda Johnston


Particle size is one of the key parameters that must be measured to ensure reproducible production of cellulose nanocrystals (CNCs) from various types of cellulose biomass and by different producers. It is also important for achieving reliable performance metrics for specific applications. Nevertheless, size measurements for CNCs are challenging due to their broad size distribution and irregular rod-shaped particles and their significant propensity to aggregate and agglomerate. We report an interlaboratory comparison (ILC) that tests protocols for image acquisition and analysis by transmission electron microscopy (TEM). Samples of CNCs on TEM grids were prepared and stained in a single laboratory and detailed data acquisition and analysis protocols were provided to participants. CNCs were imaged and the size of individual particles analyzed in ten laboratories representing a cross section of academic, industrial and government laboratories with varying levels of experience with CNCs. The data obtained showed variability in central location, width and asymmetry of the measured particle size distributions for length and width. In order to make quantitative comparisons between individual data sets and facilitate development of consensus values each data set was fit to a skew normal distribution which yields 3 parameters: the mean as a measure of the location, standard deviation as a measure of distribution width and shape as a measure of asymmetry. Consensus values were then obtained from the individual data by modelling the variation between laboratories using a skew normal distribution. This approach gave consensus values for mean, standard deviation and shape of 95.8 nm, 38.2 nm and 6.3 for length and 7.7 nm, 2.2 nm and 2.9 for width.
Analytical Chemistry


TEM, transmission electron microscopy, cellulose, nanocrystals, size distribution, interlaboratory


Bonevich, J. , Meija, J. , Michael, B. , Couillard, M. , Cui, K. , Foster, J. , Fox, D. , Heidelmann, M. , , B. , Ren, L. , Stefaniak, A. , Theissmann, R. , de, N. and Johnston, L. (2020), Particle Size Distributions for Cellulose Nanocrystals Measured by Transmission Electron Microscopy: An Interlaboratory Comparison, Analytical Chemistry, [online], (Accessed June 24, 2024)


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Created October 5, 2020, Updated March 1, 2021