Gas-phase ion dynamics in a periodic-focusing DC ion guide

Increased ion transmission in IMS: A high resolution, periodic-focusing DC ion guide ion mobility spectrometer

“…We previously showed that under similar conditions the mobility separation corresponds to low-field conditions for large molecule ions, i.e., peptides of the size examined in this study [31]. A more rigorous theoretical treatment of the focusing mechanism, which includes consideration of the effective ion temperature (T eff ), of the PDC IG is presented elsewhere [37]. (molecular weight = 720 Da) for three electrode geometries.…”

“…This value can be compared to that of electrode configuration A, which refocuses radially diffusing ions to the center of the cell, and provides a 40-fold increase in ion transmission versus uniform field electrodes. This focusing effect becomes more pronounced with decreasing inner diameter due to an increase in the effective potentials felt by an ion at an equivalent radial position [37]. This is evident from the increased ion transmission of electrode configuration A compared to electrode configuration B.…”

“…Experiments were also performed on a 125 cm drift cell composed of 100 individual electrodes of similar design to that of the 63 cm drift cell. All ion mobility experiments presented herein were conducted at room temperature (∼300 K), and this temperature was used to calculate the E/N from the experimental value of E/p [31,37]. Specific operating conditions used in obtaining individual ion mobility spectra are given in the relevant figures and captions.…”

Isomer separation of polybrominated diphenyl ether metabolites using nanoESI-TIMS-MS

“…Different variants of ion mobility spectrometry have been successfully coupled to mass spectrometry (e.g., periodic focusing DC ion guide (Gillig et al 2004; Gillig and Russell 2001; Silveira et al 2010), segmented quadrupole drift cell (Guo et al 2004), multistage IMS (Glaskin et al 2010; Koeniger et al 2006; Kurulugama et al 2009), field asymmetric waveform IMS (Kolakowski and Mester 2007; Purves and Guevremont 1999), travelling wave IMS (Shvartsburg and Smith 2008), trapped ion mobility spectrometry (Fernandez-Lima et al 2011a; Fernandez-Lima et al 2011b; Hernandez et al 2014), and cyclic drift tube mobility spectrometry (Glaskin et al 2013; Merenbloom et al 2009). In particular, TIMS-MS has proved to provide high mobility resolution separations (R~150–300) (Hernandez et al 2014; Silveira et al 2014) and the measurement of accurate mobility values using first principles (Hernandez et al 2014).…”

Theoretical predictor for candidate structure assignment from IMS data of biomolecule-related conformational space

“…[30–32] Although a number of enhanced sampling methods have been developed to reduce the computation time, further improvements are needed to efficiently correlate the theoretical results with experimental data. During the development of contemporary IMS analyzers (e.g., periodic focusing DC ion guide [33–35], segmented quadrupole drift cell [36], multistage IMS [37–39], field asymmetric IMS [40], and transient wave ion guide [41, 42]), a common pursuit has been to increase IMS resolving power, ion transmission and sensitivity. [13, 43–50] We have recently introduced the trapped ion mobility spectrometer (TIMS) [51–53].…”