Sub-50 nm colloidal nanoparticle quantification via liquid-to-aerosol conversion through control of non-volatile...

Quantitative measurement of silica nanoparticles (NPs) in liquid, particularly below 20 nm, remains fundamentally constrained by background artifacts and detection limits that are poorly understood. Here, we identify and systematically resolve a commonly underrecognized limitation in liquid-to-aerosol nanoparticle metrology: interference from dissolved non-volatile residues (NVRs) that generate artifact aerosol modes and easily interfere with NP measurements. Through mechanistic analysis of droplet formation, NVR-derived size scaling, transport losses, and charge efficiency, we establish a quantitative framework that defines the measurable concentration and size limits of aerosolization-based nanoparticle characterization. By integrating droplet-size control (via impactor coupling and electrospray tuning) with liquid-phase purification, NVR-derived artifacts are largely suppressed, enabling clear resolution of target nanoparticle peaks down single-digit nanometer range. Unified correlation equations for silica and gold NPs are developed to account for transport losses and sample feeding rate, defining practical concentration limits. An aerosolization-CPC method that avoids particle loss in DMA classification was further evaluated. Finally, the aerosolization-based method with effective NVR control is validated in membrane filtration tests where bimodal 10/20 nm silica peaks are resolved for membrane retention quantification. This work establishes a transferable metrological framework that extends liquid-phase nanoparticle quantification beyond current limitations, providing operating guidelines for reliable sub-50 nm measurements using aerosolization-based techniques.