Development of a Structure for Lossless Ion Manipulations (SLIM) High Charge Capacity Array of Traps

Abstract

Enhancing the sensitivity of low-abundance ions in a complex mixture without sacrificing measurement throughput is highly desirable. This work demonstrates a way to greatly improve the sensitivity of ion mobility (IM)-selected ions by accumulating them in an array of high-capacity ion traps located inside a novel structures for lossless ion manipulations ion mobility spectrometer (SLIM-IMS) module. The array of ion traps used in this work consisted of seven independently controllable traps. Each trap was 386 mm long and possessed a charge capacity of ∼4.5 × 10 8 charges, with a linear range extending to ∼2.5 × 10 8 charges. Each ion trap could be used to extract a peak (or ions over a mobility range) from an ion mobility separation based on arrival time. Ions could be stored without losses for long times (>100 s) and then released all at once or one trap at a time. It was possible to accumulate large ion populations by extracting and storing ions over repeated IM separations. Enrichment of up to seven individual ion distributions could be performed using the seven independently controllable ion traps. Additionally, the ion trapping process effectively compressed ion populations into narrow peaks, which provides a greatly improved basis for subsequent ion manipulations. The array of high charge capacity ion traps provides a flexible addition to SLIM and a powerful tool for IMS-MS applications requiring high sensitivity.

Evaluating Ion Accumulation and Storage in Traveling Wave Based Structures for Lossless Ion Manipulations

“…Supporting Information Figure S4 indicates that the charge-transfer product increases at longer ion residence times. A similar phenomenon was observed in a previous work where large populations of ions were stored for extended times . Higher TW amplitudes also increase the neurotensin (2+) signal, presumably due to higher ion heating, which may accelerate such reactions.…”

“…A similar phenomenon was observed in a previous work where large populations of ions were stored for extended times. 36 Higher TW amplitudes also increase the neurotensin (2+) signal, presumably due to higher ion heating, which may accelerate such reactions. Similar results were observed for tracks 4 and 5, where the track width is ∼2× that of tracks 1 and 2, Supporting Information Figures S5 and S6.…”

Accumulation of Large Ion Populations with High Ion Densities and Effects Due to Space Charge in Traveling Wave-Based Structures for Lossless Ion Manipulations (SLIM) IMS-MS

“…In this regard, we have recently demonstrated effective ion accumulation and extended storage after selection f rom IMS separations using very low TW amplitudes in SLIM trapping regions. 53 The present data show the ion populations (TIS) shift closer to the gate with increased TW amplitude or time as well as a dramatic effect on the size of the accumulated ion populations.…”

“…We note also that similar proton transfer processes have also recently been observed for larger numbers of ion trapping events (i.e., accumulation of larger ion populations) and in a SLIM array of traps using a similar ion confinement gate arrangement. 53 Figure 5 shows data for the two charge states of Neurotensin (3+ and 2+; m/z 558 and 836) as well as its two prominent fragments (y, 10 m/z 643 and y, 11 m/z 724; peaks i and f in Figure 3) for different ion accumulation times. The data are also given on normalized scales for the longest accumulation times (Figure 5C,D insets) to better show the differences in peak arrival times.…”

SLIM Tricks: Tools, Concepts, and Strategies for the Development of Planar Ion Guides

“…SLIM separations are logically complemented by mass spectrometry, and the ability to deftly manipulate ions further extends the analytical utility of the hybrid instrumental technique. A novel system constructed by researchers at EPFL couples a multipass SLIM IMS system with a TOF-MS, but importantly can also direct ions to a cryogenic trap where they are stored for messenger tagging vibrational spectroscopy. − Performing collision-induced dissociation of ions in switchable subsections of the SLIM before passing to the cryo-IR module enables specific fragmentation analysis and increases structural knowledge generally. , Additionally, binary multiplexing strategies have been explored on this instrument, drastically increasing the rate of spectroscopic fingerprinting for mobility-selected species. , To date, few research academic groups have independently realized functioning TW-SLIM experiments. − The impressive performance of TW-SLIM demonstrates its potential for both analytical and preparative separations. Consequently, broader access to development resources is needed to facilitate experimentation.…”