Figures & data
Figure 1. Scheme of the bipolar electrospray chamber with front and back windows; two gray connectors (PEEK) oriented at 90° bringing in one positive and one negative capillary emitter, and gas inlet (right) and outlet (left) connections. A stainless steel grid 30% transparent is symmetrically placed between the capillaries to decouple them electrostatically. An additional image is included in the SI.
Figure 2. Bipolar spectra obtained when spraying (a) MC5I+FAP− and (b) C7+Br−, both dominated by a resolvable series of singly charged clusters A+nB−n±1. The original spectrum format (a) is compacted in (b) by using absolute values for the current.
Figure 3. High-resolution bipolar mobility spectrum for MC5I+FAP−, exhibiting 43 resolvable peaks in each polarity.
Figure 4. Peak width for the C7+Br− negative clusters obtained by Gaussian fitting the spectrum of .
Figure 5. Resolution (1/FWHM) for the Halfmini DMA challenged with MC5I+FAP− (a) and C4+TPB− clusters (b), demonstrating resolving powers >50 with sufficiently large particles.
Figure 6. Bipolar spectrum obtained with the Herrmann DMA for EMI+Methide− clusters.
Figure 7. Resolution for the Hermann DMA with EMI+Methide−, limited by diffusion in the DMA.
Table 1. Ions and salts tested.
Table 2. Relation between classification voltage and mobility Z for four of the ions used.