The project will establish reference materials, assess and compare the performance of different techniques, initiate pre-normalisation studies and provide input to internationally accepted standards. Work has been structured into three technical Work Packages, as well as a Work Packages to ensure the project’s impact is fully achieved. : Work Package 1: Particle Number Concentration Work Package 2: Agglomerate Fraction and Non-Spherical Particles Work Package 3: Surface Chemistry Work Package 4: Impact Overall, expected final results are as follows: Particle concentration Accurate methods to measure particle concentrations in liquid suspension and reference materials to calibrate laboratory instrumentation will be developed. A means of calculating the uncertainty of such measurements will also be established. Non-spherical particles Protocols to determine the fraction of agglomerates in a suspension of monodisperse primary particles will be defined. This work includes the generation of test materials for agglomerate fraction measurements. (see Work Package 2) Chemical composition and thickness of the shell A method for calibrating XPS instrumentation and translating spectral intensities into surface chemistry of nanoparticles will be developed. Through accurate calculations the uncertainty of such measurements will be established for the first time. (see Work Package 3) Good practice guide The methods for the measurements described above will be validated in two inter-laboratory studies which will enable valid, routine monitoring and quality control of particle concentration and surface chemistry for nanoparticle-based formulations and products. These methods will be disseminated through a good practice guide, peer-reviewed papers, conferences, dedicated workshops and websites to ensure the widest possible benefit. (see Work Package 4) Engagement with industry A dedicated and industry-focussed workshop will be held toward the end of the project. Furthermore, we will contribute to three new documentary standards, hold a training course, produce a textbook and develop an e-learning course to disseminate the results of this project and good practice in measuring particle concentration and surface chemistry. (see Work Package 4)