Figure 2.

spICP-MS intensity spectrum as a function of DMA scanning time for 60 nm AuNPs. Single particle events are presented as red spikes. The $d_{m,t}$ selected by the DMA with respect to time is represented by the stepped blue line following Eq. 4 ($d_{m,0}=20\hspace{0.33em}\text{nm}$, $d_{m,step}=2\hspace{0.33em}\text{nm}$, and $t_{step}=31\hspace{0.33em}\text{s}$). Two major populations representing singly and doubly charged 60 nm AuNPs are highlighted by the black brackets. Inset shows operational features of DMA-spICP-MS relevant to data acquisition (Eq. 4).