Standardization and validation of a protocol of zeta potential measurements by electrophoretic light scattering for nanomaterial characterization

•A methodology to validate a protocol evaluating zeta potential by ELS was proposed.•A validation of a protocol was achieved using a negative and a positive standard.•The expanded uncertainty was less than 15% for both standards.•The protocol was found robust, accurate and consistent with standard ISO.•The protocol was suitable to evaluate the zeta potential of polymer nanomaterials.