Analysis of engineered nanomaterials (Ag, CeO2 and Fe2O3) in spiked surface waters at environmentally relevant particle concentrations

Abstract Quantification of engineered nanomaterials (ENMs) concentrations in surface waters remains one of the key challenges in environmental nanoscience and nanotechnology. A promising approach to estimate metal and metal oxide ENM concentrations in complex environmental samples is based on the increase in the elemental ratios of ENM-contaminated samples relative to the corresponding natural background elemental ratios. This contribution evaluated the detection and quantification of Ag, CeO2, and Fe2O3 ENMs spiked in synthetic soft, or in natural river waters using the elemental ratio approach, and evaluated the effect of extractants including sodium hydroxide (NaOH), sodium oxalate (Na2C2O4) and sodium pyrophosphate (Na4P2O7) on the recovery of ENMs from the spiked waters. The extracted ENM concentrations were higher in Na4P2O7-extracted suspensions than in NaOH- and Na2C2O4-extracted suspensions due to the higher efficiency of Na4P2O7 to break up natural and engineered nanomaterial heteroaggregates. The size distributions of the extracted suspensions were determined by asymmetrical flow-field flow fractionation coupled to inductively coupled plasma-mass spectrometer (AF4-ICP-MS). These size distribution analysis demonstrated that Ag ENMs were extracted from the spiked river water as both primary particles and small (