Figure 4.
(a) Ion-current measurements for melittin ions in the straight (blue) and elevator (red) modes as a function of the voltage difference between the two orifices in elevator surface (see Figure 1). Ion currents of ~350 pA were measured at the device entrance. (b) Top panel shows trajectories at ΔV = 0 V (i.e., straight mode), middle panel at ΔV = −2 V showing 66% transmission through the elevator, and the bottom panel shows the ion trajectories at ΔV = −4 V and 100% transmission through the elevator. Simulations were performed with 250 particles using rf parameters of 150 Vp-p at 1 MHz.