Minseop Kim (Hanyang university)

Tae Hyun Yoon (Hanyang university)

Minseop Kim (Hanyang university)

Seung Min Ha (Hanyang university)

Yewon Han (Hanyang university)

Tae Hyun Yoon (Hanyang university)

The precise quantification and characterization of nanoparticles (NPs) and biological colloids, such as extracellular vesicles (EVs), are fundamental to advancing nanomedicine and environmental safety. While single-particle inductively coupled plasma mass spectrometry (spICP-MS) is a premier tool for nano-sized particle analysis, its sensitivity in number concentration and size accuracy is frequently hampered by background noise and the limitations of intensity-based thresholding. This often results in the exclusion of legitimate signals from small particles or the misidentification of dissolved ions as particulate events.

Here, we introduce an isotope ratio filtering (IRF) method for spICP-TOF-MS that leverages natural isotopic abundances to validate authentic particle signals through coincidence analysis via examples of silver nanoparticles (AgNPs) and extracellular vesicles (EVs). This technique is also uniquely suited for characterizing colloidal behaviors; by exploiting isotopic coherence, it distinguishes intact particles from dissolved analyte fractions (dissolution) and enables the resolution of complex populations including fragments, primary particles, and clusters (aggregation/agglomeration).