Nested-channel for on-demand alternation between electrospray ionization regimes

Abstract

Nested electrospray ionization alternates on-demand between microscale main-channel and nanscale sub-channels.

Conducting and Characterizing Femto Flow Electrospray Ionization

“…In comparison, the flow rate is more than three orders of magnitude lower than that of a typical nanoESI. 9,21 This confirms the improved overall ionization and transmission efficiency at lower flow, which aligns with previous observation with lower current ion beams. 16 Interestingly, the ion intensity produced by fA ESI 16 (Fig.…”

“…Femtoamp electrospray ionization (fA ESI) was developed using both micrometer and submicron emitter tips. 16 The observed MS intensities, being 2-3 orders of magnitude lower than those produced by a 50 pL/min ESI, 17 suggest that the flow rates for these emitter tips could be in the femto range. These new findings bring challenges and exciting opportunities for the characterization and further development of low flow electrospray ionization.…”

“…[4][5][6] Reducing the flow rate for ESI is one continued research direction and the lower limits reported for micrometer emitter tips range 30-300 pL/min. [7][8][9]…”

“…This suggests that the hexane layer effectively prevented charge flow inside the emitter. In the case of relay ESI, charge transport through the exterior space 9 was not interfered by the hexane layer. By using a wire-in submicron emitter tip as the primary source, adjustable flux (130 fA-2 nA) 16 of charge may be deposited onto the secondary emitter to trigger the ionization of the sample solution.…”

Conducting and characterizing femto flow electrospray ionization

“…4–6 Reducing the flow rate for ESI is a continuing research direction with lower limits being reported for micrometer emitter tips in the range of 30–300 pL min −1 . 7–9…”