A Sensitive Single Particle-ICP-MS Method for CeO2 Nanoparticles Analysis in Soil during Aging Process.

The increasing prevalence of products that incorporate engineered nanoparticles (ENPs) has prompted efforts to investigate the potential release, environmental fate, and exposure of the ENPs. However, the investigation of cerium dioxide nanoparticles (CeO2 NPs) in soil has remained limited, owing to the analytical challenge from the soil's complex nature. In this study, this challenge was overcome by applying a novel single particle-inductively coupled plasma-mass spectrometry (SP-ICP-MS) methodology to detect CeO2 NPs extracted from soil, utilizing tetrasodium pyrophosphate (TSPP) aqueous solution as an extractant. This method is highly sensitive for determining CeO2 NPs in soil, with detection limits of size and concentration of 15 nm and 194 NPs mL-1, respectively. Extraction efficiency was sufficient in the tested TSPP concentration range from 1 mM to 10 mM at a soil-to-extractant ratio 1:100 (g mL-1) for the extraction of CeO2 NPs from the soil spiked with CeO2 NPs. The aging study demonstrated that particle size, size distribution, and particle concentration underwent no significant change in the aged soils for a short period of one month. This study showed an efficient method capable of extracting and accurately determining CeO2 NPs in soil matrices. The method can serve as a useful tool for nanoparticle analysis in routine soil tests and soil research.