Quantifying Chemical Composition and Reaction Kinetics of Individual Colloidally Dispersed Nanoparticles

To control a nanoparticle's chemical composition and thus function, researchers require readily accessible and economical characterization methods that provide quantitative in situ analysis of individual nanoparticles with high throughput. Here, we established dual analyte single-particle inductively coupled plasma quadrupole mass spectrometry to quantify the chemical composition and reaction kinetics of individual colloidal nanoparticles. We determined the individual bimetallic nanoparticle mass and chemical composition changes during two different chemical reactions: (i) nanoparticle etching and (ii) element deposition on nanoparticles at a rate of 300+ nanoparticles/min. Our results revealed the heterogeneity of chemical reactions at the single nanoparticle level. This proof-of-concept study serves as a framework to quantitatively understand the dynamic changes of physicochemical properties that individual nanoparticles undergo during chemical reactions using a commonly available mass spectrometer. Such methods will broadly empower and inform the synthesis and development of safer, more effective, and more efficient nanotechnologies that use nanoparticles with defined functions.

Automated summary

By using dual analyte single-particle inductively coupled plasma quadrupole mass spectrometry, researchers were able to quantify the mass and chemical composition changes of individual colloidal nanoparticles during two different chemical reactions. This study revealed the heterogeneity of chemical reactions at the single nanoparticle level, providing a framework for understanding the dynamic changes of physicochemical properties in nanoparticles during chemical reactions.