• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.852-857
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• 2017

In this paper, measurements of ion mobility were performed in oxygen at gas pressures of 44.52 - 101.19 kPa using the drift tube method. Over this pressure range, mobility values were within the limits of 1.796 to $3.821cm^2{\cdot}V^{-1}{\cdot}s^{-1}$ were determined and ion mobility shown to decrease non-linearly with increasing gas pressure towards a certain level of saturation. Ion mobility measured in air was lower than that measured in oxygen at the same gas pressure. Finally, a parameter correction method for calibrating the relationship between the ion mobility and gas pressure in oxygen was proposed.

• Mass Spectrometry Letters
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• v.8 no.4
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• pp.79-89
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• 2017

Ion mobility mass spectrometry (IM-MS) combines the advantages of ion mobility spectrometry (IMS) and MS for effective gas-phase ion analysis. Separation of ions based on their mobilities prior to MS can be performed without a great loss in other analytical figures of merit, and the extra dimension of analysis offered by IM can be beneficial for isomer and complex sample analyses. In this review, basic principles of IMS and IM-MS are described in addition to an introduction to various IMS techniques and commercial IM-MS instruments. The nature of collision cross-section (${\Omega}_D$), an important parameter determining the transport properties of ions in IMS, is also explained in detail.

• Mass Spectrometry Letters
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• v.12 no.4
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• pp.137-145
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• 2021

Herein we report multiple ion mobility (IM) peaks in electrospray ionization IM mass spectrometry (ESI-IM-MS) produced by glutamine residue in peptide. The mobility features of 147 peptides were investigated using ESI-IM-MS combined with liquid chromatography. Of these peptides, 66 presented multiple IM peaks, and analysis of their sequence using collision induced dissociation (CID) revealed that glutamine (Gln), as well as proline (Pro), plays a critical role in generating multiple IM peaks. Mutant-based investigations using Gln-containing peptides indicate that the side chain of Gln promotes intermolecular interactions, inducing multiple structures of the peptide ions in the gas phase. Consequently, the present study demonstrates that the distinct ion mobility signatures identified herein can potentially be used to characterize glutamine-containing peptide ions.

• Mass Spectrometry Letters
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• v.11 no.4
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• pp.65-70
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• 2020

Despite its great success in the field of proteomics, mass spectrometry has limited use for determining structural details of peptides, proteins, and their assemblies. Emerging ion mobility spectrometry-mass spectrometry has enabled us to explore the conformational space of protein ions in the gas phase, and further combinations with the gas-phase ion spectroscopy and the collision-induced unfolding have extended its abilities to elucidating the secondary structure and local details of conformational transitions. This review will provide a brief introduction to the combined approaches of IMS-MS with gas-phase ion infrared spectroscopy or collision-induced unfolding and their most recent results that successfully revealed higher-order structural details.

• Mass Spectrometry Letters
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• v.12 no.4
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• pp.152-158
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• 2021

Electrospray ionization (ESI) and ion mobility spectrometry-mass spectrometry (IMS-MS) were employed to investigate the solvated structures of ionic species in the lithium iodide electrolyte solution in the gas phase. The Li⁺I^-Li⁺ triple ion and single standalone Li+ ions solvated by 1,4-dioxane were successfully generated and observed by ESI-MS under the influence of dioxane vapor at the inlet region. Under the present experimental condition, (1,4-dioxane)_m·Li⁺ complex ions (m = 1, 2, and 3) and a (1,4-dioxane)·Li⁺I^-Li⁺ complex ion were observed, which were further examined by IMS to investigate their structures. The presence of multiple structural isomers was confirmed, which accounts for the endothermic conformational transition of 1,4-dioxane from a chair to a boat to achieve bidentate O-donor binding to Li⁺ and Li⁺I^-Li⁺. Further structural details critical for the ion-solvent interactions were also examined and discussed with the help of density functional theory calculations.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.11
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• pp.1007-1013
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• 1998

In this paper, the dielectric properties of fabricated Polyvinylidene fluoride(PVDF, $PVF_2$) thin film with substrate temperature from 30 to at vapor deposition. The dielectric properties of PVDF thin film had been studied in the frequency range from 10Hz to 4MHz at measuring temperature between 20 and $100^{/circ}C$. The anomalous increasing in dielectric constant and dielectric loss at low frequencies and high temperature was described for PVDF thin film containing ion impurities. In particularly, ion mobility of fabricated PVDF thin film at substrate temperature at $30^{/circ}C$ decrease from $2\times10^{-5}\;to\;3.07$\times10^{-7}cm^2/V.s$ On the other hand, ion density increase abruptly from 1.49\times$$10^{13}$ to $1.5\times$10^{16}$cm^{-3}$ In spite of decreasing of ion mobility, dielectric constants and dielectric loss for PVDF thin film increase rapidly with decreasing frequency and high temperature. It was concluded that the dielectric constants and dielectric loss was related to ion density than to ion mobility at low frequency and high temperatures.

• Proceedings of the KIEE Conference
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• 1988.11a
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• pp.249-251
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• 1988

In this paper, the negative ion mobility of $SF_6$ is determined using as a negative ion detector the burst pulse which is triggered in a positive point-plane gap by electrons detached from negative ions near the anode point. The result obtained for the negative ion mobility for zero field at atmospheric pressure is $0.57cm^2v^{-1}s^{-1}$.

• Journal of the Korean Chemical Society
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• v.6 no.1
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• pp.29-31
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• 1962

Paper electrophoresis of aluminium ion was studied using a closed horizontal type apparatus. The optimal conditions of voltage, pH of electrolytic supporting solution and migration time were determined for the electrophoretic migration of the ion on the paper strip saturated by Michaelis buffer solution. The mobility of the ion and the isoelectric point of $Al(NO_3)_3$ solution were $(1.004{\pm}0.0020){\times}10^{-4}\;cm^2\;sec^{-1}\;volt^{-1}$ at pH = 2.38 and pH = 3.23 respectively.

• Journal of the Korean Society of Industry Convergence
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• v.26 no.1
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• pp.27-34
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• 2023

This study conducted a study on a small-capacity PCS using lithium-ion batteries used in personal mobility. Most of the batteries in Personal Mobility only charge with external chargers and are used only as mobile energy sources. However, this paper aims to charge the battery of PM using PV and system power or to use the charged power as a stand-alone power supply. The developed PCS can be operated as a two-channel battery charger/discharger, a battery charger using solar power, and a stand-alone solar inverter depending on the operation method. The validity of the manufactured small-capacity PCS was verified through experiments.

• Mass Spectrometry Letters
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• v.15 no.2
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• pp.95-106
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• 2024

Taraxacum coreanum, known as the native Korean white dandelion, has been historically used in traditional medicine due to its various therapeutic properties. However, the specific benefits and mechanisms of white dandelion in alleviating particular symptoms or diseases remain uncertain due to the complexity of its phytochemical profile. In this study, we aimed to elucidate the phytochemical profiles of methanolic extracts of different parts of the white dandelion (flower, leaf, stem, and root) using hybrid ion-mobility Q-TOF MS. Using the trapped ion mobility-based PASEF technique, 3715 and 2114 molecular features with MS2 fragments were obtained in positive and negative ion modes, respectively, and then a total of 360 and 156 phytochemical compounds were annotated by matching with a reference spectral library in positive and negative ion modes, respectively. Subsequent feature-based molecular networking analysis revealed the phytochemical differences across the four different parts of the white dandelion. Our findings indicated that the methanolic extracts contained various bioactive compounds, including lipids, flavonoids, phenolic acids, and sesquiterpenes. In particular, lipids such as linoleic acids, lysophosphatidylcholines, and sesquiterpenoids were predominantly present in the leaf, while flavonoid glycosides and lysophosphoethanolamines were notably enriched in the flower. An assessment of the total phenolic content (TPC) and total flavonoid content (TFC) of the methanolic extracts revealed that the majority of phytochemicals were concentrated in the flower. Interestingly, despite the root extract displaying the lowest TPC and TFC values, it exhibited the highest radical scavenging rate when normalized to TPC and TFC, suggesting a potent antioxidant effect. These findings and further investigations into the biological activities and medicinal potential of the identified compounds, particularly those exclusive to specific plant parts, may contribute to the development of novel therapeutic agents derived from white dandelion.