Uncertainties of size measurements in electron microscopy characterization of nanomaterials in foods

Agnieszka Dudkiewicz; Alistair B A Boxall; Qasim Chaudhry; Kristian Mølhave; Karen Tiede; Peter Hofmann; Thomas P J Linsinger

doi:10.1016/j.foodchem.2014.12.071

Uncertainties of size measurements in electron microscopy characterization of nanomaterials in foods

Food Chem. 2015 Jun 1:176:472-9. doi: 10.1016/j.foodchem.2014.12.071. Epub 2015 Jan 3.

Authors

Agnieszka Dudkiewicz¹, Alistair B A Boxall², Qasim Chaudhry³, Kristian Mølhave⁴, Karen Tiede³, Peter Hofmann⁵, Thomas P J Linsinger⁶

Affiliations

¹ The Food and Environment Research Agency, Sand Hutton, York Y041 1LZ, UK; The University of York, Heslington, York YO10 5DD, UK. Electronic address: agnieszkaidudkiewicz@gmail.com.
² The University of York, Heslington, York YO10 5DD, UK.
³ The Food and Environment Research Agency, Sand Hutton, York Y041 1LZ, UK.
⁴ Deptartment of Micro and Nanotechnology, Technical University of Denmark, Ørsteds Plads 345E, 2800 Kongens Lyngby, Denmark.
⁵ Department of Geoinformatics - Z_GIS, University of Salzburg, Schillerstr. 30, 5020 Salzburg, Austria.
⁶ Joint Research Centre, Institute for Reference Materials and Measurements, Retieseweg 111, 2440 Geel, Belgium.

PMID: 25624258
DOI: 10.1016/j.foodchem.2014.12.071

Abstract

Electron microscopy is a recognized standard tool for nanomaterial characterization, and recommended by the European Food Safety Authority for the size measurement of nanomaterials in food. Despite this, little data have been published assessing the reliability of the method, especially for size measurement of nanomaterials characterized by a broad size distribution and/or added to food matrices. This study is a thorough investigation of the measurement uncertainty when applying electron microscopy for size measurement of engineered nanomaterials in foods. Our results show that the number of measured particles was only a minor source of measurement uncertainty for nanomaterials in food, compared to the combined influence of sampling, sample preparation prior to imaging and the image analysis. The main conclusion is that to improve the measurement reliability, care should be taken to consider replications and matrix removal prior to sample preparation.

Keywords: Electron microscopy; Food; Measurement uncertainty; Minimal sample intake; Nanomaterials.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Food Analysis / methods*
Microscopy, Electron / methods*
Nanostructures / chemistry*
Reproducibility of Results