Single-particle inductively coupled plasma time-of-flight mass spectrometry (sp-ICP-TOFMS) is a powerful analytical technique that is used to detect and quantify inorganic nanoparticles across a broad spectrum of applications. As spICP-TOFMS continues to develop into a established tool for nanoparticle analysis, our recent research has focused on improving absolute TOF spectra acquisition speeds to monitor fast transient events. Previously, continuous data acquisition on the icpTOF required on-digitizer spectral averaging prior to writing data to disk, and was limited to 1-3 ms per spectrum (1000-333 Hz). While no data is lost through on-digitizer averaging, the time-averaged output could be limiting for some applications. Through the development of new digitizer firmware, we are now able to record complete elemental mass spectra at the native frequency of TOFWERK analyzers; 83 kHz for icpTOF-S2, 33 kHz for icpTOF-R, and 21 kHz for icpTOF-R2. Fast acquisition allows for the analysis of individual particles or particle clouds from ultra-fast laser ablation (LA) imaging, in which transients events are less than 500 ms.

Here, we report results from continuous data collection at 12 μs with the TOFWERK icpTOF-S2 instrument. The fundamental principle of spICP-TOFMS involves measuring low-concentration particle suspensions at high data acquisition speed. This allows to discriminate discrete particle events from background noise. We examine the impact of different integration times, ranging from 12 µs to 1200 µs, on the differentiation of signals from background noise, as well as the quantification of mass, size, and particle number concentration (PNC). We report on the evaluation of commercially available spherical Au and AgAu core-shell nanoparticles, and monodisperse multielement solution droplets produced by a droplet generator.