Introducing “time-of-flight single particle investigator” (TOF-SPI): a tool for quantitative spICP-TOFMS data analysis

Single-particle time-of-flight mass spectrometry (spICP-TOFMS) is quickly becoming an established method for the measurement, quantification, and classification of diverse populations of metal-containing nanoparticles (NPs) and submicron particles (μPs). As researchers begin to acquire larger multi-sample spICP-TOFMS datasets, robust batch-analysis programs are essential. To meet this need, our lab has developed and tested a set of spICP-TOFMS data analysis programs called “time-of-flight single particle investigator” or “TOF-SPI.” These programs are written in LabVIEW and are now available for use as a Windows executable program. TOF-SPI is developed for the analysis of data from icpTOF (TOFWERK AG) instruments and works directly with the instrument-generated HDF5 files. TOF-SPI is a data analysis program that assimilates years of spICP-TOFMS data analysis strategies to provide accurate single-particle finding, split-event correction, quantification of number concentrations, quantification of element mass amounts per particle, and generation of user-readable output reports. TOF-SPI is capable of performing batch analyses of spICP-TOFMS data calibrated with either the particle-size method or online microdroplet calibration. Here, we report the basic operating principles of TOF-SPI.