TY - JOUR T1 - Evaluation of a TEM based Approach for Size Measurement of Particulate (Nano)materials JF - Materials Y1 - 2019 A1 - Eveline Verleysen A1 - Thorsten Wagner A1 - Hans-Gerd Lipinski A1 - Ralf Kägi A1 - Robert Koeber A1 - Ana Boix-Sanfeliu A1 - Pieter-Jan De Temmerman A1 - Jan Mast KW - electron microscopy KW - European Commission’s Recommendation for a definition of a nanomaterial KW - image analysis KW - Method validation KW - nanomaterial KW - particulate material AB -

An approach for the size measurement of particulate (nano)materials by transmission electron microscopy was evaluated. The approach combines standard operating procedures for specimen preparation, imaging, and image analysis, and it was evaluated on a series of certified reference materials and representative test materials with varying physical properties, including particle size, shape, and agglomeration state. The measurement of the median value of the minimal external particle diameter distribution was intra-laboratory validated. The validation study included an assessment of the limit of detection, working range, selectivity, precision, trueness, robustness, and ruggedness. An uncertainty that was associated to intermediate precision in the range of 1–7% and an expanded measurement uncertainty in the range of 7–20% were obtained, depending on the material and image analysis mode. No bias was observed when assessing the trueness of the approach on the certified reference materials ERM-FD100 and ERM-FD304. The image analysis method was validated in an inter-laboratory study by 19 laboratories, which resulted in a within-laboratory precision in the range of 2–8% and a between-laboratory precision of between 2% and 14%. The automation and standardization of the proposed approach significantly improves labour and cost efficiency for the accurate and precise size measurement of the particulate materials. The approach is shown to be implementable in many other electron microscopy laboratories.

VL - 12 CP - 14 M3 - 10.3390/ma12142274 ER -