Discrimination and Quantification of Soil Nanoparticles by Dual-Analyte Single Particle ICP–QMS

This study presents the new application of dual-analyte single particle inductively coupled plasma quadrupole mass spectrometry (spICP–QMS) to the discrimination and quantification of two typical soil nanoparticles (kaolinite and goethite nanoparticles, abbr. KNPs and GNPs) in three samples (SA, SB, and SC) with three detection events (Al unpaired event, Fe unpaired event, and paired event). SA was mainly composed of KNPs with a concentration of 28 443 ± 817 particle mL–1 and a mean particle size of 140.7 ± 0.2 nm. SB was mainly composed of GNPs with a concentration of 39 283 ± 702 particle mL–1 and a mean particle size of 141.8 ± 2.9. In SC, the concentrations of KNPs and GNPs were 22 4541 ± 1401 and 70 604 ± 1623 particle mL–1, respectively, and the mean particle sizes of KNPs and GNPs were 140.7 ± 0.2 and 60.2 ± 0.3 nm, respectively. The accuracy of dual-analyte spICP–QMS was determined by spiking experiments, comparing these results with the measurements of other techniques, analyzing the samples in different SA and SB proportions and in different SC concentrations. Our results demonstrated that the dual-analyte spICP–QMS is a promising approach to distinguishing different kinds of natural NPs in soils.