Separating Dissolved Silver from Nanoparticulate Silver is the Key: Improved Cloud-Point-Extraction Hyphenated to Single Particle ICP-MS for Comprehensive Analysis of Silver-Based Nanoparticles in Real Environmental Samples Down to Single-Digit nm Particle Sizes

Abstract Investigating silver-based nanoparticles (Ag-b-NPs) in environmental samples is challenging with current analytical techniques, owing to their low concentrations (ng L−1) in the presence of high quantities of dissolved Ag(I) species. sp-ICP-MS is a promising technique able to simultaneously determine the concentration and particle sizes of Ag-b-NPs even at concentrations of several ng L−1. However, sp-ICP-MS suffers from the coexistence of dissolved analyte species causing high background signals. These background signals cover particle signals and therefore limit the size detection limit (SDL) in sp-ICP-MS. Ag-b-NPs in environmental samples exhibit diameters of