Stepwise Optimization of Traveling Wave Profiles and Inverse Gating Pattern in Structure for Lossless Ion...

The Structure for Lossless Ion Manipulation (SLIM) platform is a powerful analytical separation tool allowing ultra-long serpentine separation path spanning hundreds of meters. In SLIM, transient fields called Traveling waves (T-wave) roll over the ions leading to separation, hence a Stepwise optimization of experimental operating conditions including amplitude, speed, and shape is essential. Here, we have characterized seven T-wave profiles including sine, triangle, square, ramp, reverse ramp, and two decreasing fields as a function of obtained resolution, resolving power and signal intensities. We found out that T-wave patterns with the most uniform electric field and least negative electric fields produce the highest resolution (reverse ramp). Both signal intensity and resolution are favorable at mid-range T-wave amplitude and speeds. The inverse gating could potentially improve the obtained resolutions as much as 35 %, in the case of reverse ramp, within 1.5 m of separation path.