Ion Mobility Research Articles

The preparation and properties of carbon-coated fibers as solid-phase microextraction adsorbents for the determination of triacetone triperoxide in soil samples with fast and sensitive analysis using ion mobility spectrometry

Carbon-coated fibers include carbon activated/polydimethylsiloxane (CA/PDMS), graphene/ polydimethylsiloxane (Gr/PDMS), graphene quantum dots/ polydimethylsiloxane (GQD/PDMS), carbon nano-onions/polydimethylsiloxane (CNO/PDMS) and MXene/polydimethylsiloxane (MXene/PDMS) were prepared by sol–gel method, characterized by SEM, EDX and FT-IR techniques and were used by the headspace solid-phase microextraction coupled with ion mobility spectrometry (HS-SPME-IMS) method for extraction and determination of triacetone triperoxide (TATP). According to the results, MXene/PDMS was selected as the best sorbent. A response surface methodology based on a Box Behnken design (BBD) method was used to optimize critical experimental variables. Under optimal extraction conditions, the calibration graph was linear in the 50 to 1000 ng mL−1 (R2 > 0.998). Also, the detection limit and the relative standard deviations (RSDs, n = 6) were 15.1 ng mL−1 and 2.68 %, respectively. Finally, the HS-SPME-IMS method was successfully used to analyze TATP in contaminated soil samples. To check the matrix effect and the accuracy of the process, the analyte addition technique was applied (added: 50–1000 ng mL−1; determined: 48–1015 ng mL−1). The desired relative recoveries were obtained in the range of 95.3 to 104.1 %.

Using ion mobility spectrometry to understand signal dilution during tandem mass spectrometry sequencing of digital polymers: Experimental evidence of intramolecular cyclization.

Optimizing the structure of digital polymers is an efficient strategy to ensure their tandem mass spectrometry (MS/MS) readability. In block-truncated poly(phosphodiester)s, homolysis of C-ON bonds in long chains permits the release of smaller blocks amenable to sequencing. Yet the dissociation behavior of diradical blocks was observed to strongly depend on their charge state. Polymers were ionized in negative mode electrospray and activated in-source so that blocks released as primary fragments can be investigated using ion mobility spectrometry (IMS) or sequenced in the post-IMS collision cell. Collision cross sections (CCS) were derived from arrival times using a calibration procedure developed for polyanions using the IMSCal software. A multistep protocol based on quantum methods and classical molecular dynamics was implemented for molecular modeling and calculation of theoretical CCS. Unlike their triply charged homologues, dissociation of diradical blocks at the 2- charge state produces additional fragments, with +1m/z shift for those holding the nitroxide α-termination and -1m/z for those containing the carbon-centered radical ω-end. These results suggest cyclization of these diradical species, followed by H• transfer on activated reopening of this cycle. This assumption was validated using IMS resolution of the cyclic/linear isomers and supported by molecular modeling. Combining IMS with molecular modeling provided new insights into how the charge state of digital blocks influences their dissociation. These results permit to define new guidelines to improve either ionization conditions or the structural design of these digital polymers for best MS/MS readability.

The ionic conductivity and electrochemical performance of Alginate-PVA based polymer electrolyte with Li+ charge carriers for supercapacitor

This study presents the synthesis and characterization of solid polymer blend electrolytes (SPBEs) using alginate (Alg) and polyvinyl alcohol (PVA) as host polymers, incorporating lithium bis(trimethanesulfonyl)imide (LiTFSI) as the ion-providing salt for potential application in EDLCs. The surface morphology of the SPBEs was revealed using scanning electron microscopy (SEM), while thermal gravimetric analysis (TGA) demonstrates enhanced thermal stability, characterized by reduced weight loss and a shift toward higher decomposition temperature. Complexation between Alg-PVA and LiTFSI was indicated by Fourier-transform infrared spectroscopy (FTIR), as evident by the transitions and intensity changes in FTIR bands corresponding to functional groups. Increasing LiTFSI content reduces bulk resistance, with Alg-PVA containing 20 wt% LiTFSI (Li-20) showing maximum room temperature ionic conductivity (3.31 × 10-4 S cm−1) and the lowest activation energy (0.05 eV). Transport properties, analyzed using the Arof-Noor (A-N) method, reveal that ionic conductivity in SPBEs is governed by ionic mobility and ions’ diffusion coefficient. Sample Li-20 displays predominantly ionic transport with a transference number (tion) 0.98 and electrochemical stability up to 2.55 V. The EDLC, employing activated carbon electrodes and the most conductive electrolyte, demonstrates notable performance features, including specific capacitance (87.51F/g at 2 mV/s, assessed from CV), energy density (25.17 Wh kg−1), and power density (1038.92 W kg−1). Testing at various current densities reveals the highest specific capacitance values associated with the lowest current density, measuring 51.15F/g for the EDLC cell based on the Li-20 sample.

Effect of Fluorine Segments in Fluoropolymer matrix on the Properties of Gel Polymer Electrolytes

Polymer quasi‐solid electrolytes have been paid widely attention in account of their outstanding advantages in safety, flexibility, viscoelasticity and film formation. Fluoropolymer is used as matrix of gel electrolytes not only has high electrochemical stability, but also facilitates the dissociation of lithium salts owning to the strong electron‐absorbing C‐F groups, which makes it a very promising choice for the further development of gel electrolytes. Due to the different sites of C‐F bonds, their activity is also diverse, which results in the difference of the mobility of lithium ions and the LiF composition of SEI film on the surface of lithium metal anode. As a result, distinct fluorine‐containing gel polymer electrolytes are prepared by in‐situ polymerization of two different monomers, HFMA and TFMA. Compared with ‐CF3 on terminal group in TFMA, the gel electrolyte polymerized with HFMA whose C‐F group with stronger electronegativity is at the intermediate carbon site, as polymer matrix has better performance. The ionic conductivity achieves 7.02×10−3 S cm−1 at room temperature, and the assembled batteries have a capacity retention rate of 91% after 200 cycles of 1 C. Our research has laid a solid theoretical foundation for the further development of quasi‐solid electrolyte.

Enhanced ionic conductivity through B-site Zr doping in NaNbO3 solid electrolytes

Oxide ion conductors hold significance in various applications, such as electrolytes in solid oxide fuel cells. This study focuses on synthesizing and systematically investigating the structural, morphological, and electrical properties of NaNb1-xZrxO3-0.5x (0 ≤ x ≤ 0.15) solid electrolyte. X-ray photoelectron spectroscopy (XPS) analysis shows that introducing a small quantity of zirconium into NaNbO3 induces an environment of unbalanced charge neutrality, creating oxygen vacancies. This phenomenon establishes a pathway for the mobility of oxygen ions. Temperature-dependent ac conductivity, analyzed through impedance data, follows Jonscher's power law, with the 's' parameter indicating a correlated barrier hopping mechanism. Enhanced conductivity is observed with Nb5+ substitution by Zr4+. The reduced activation energy value is observed for x = 0.1, which suggests enhanced ion hopping and, hence, enhanced conductivity. NaNb0.9Zr0.1O2.95 exhibits predominantly ionic conduction with a total conductivity of 6.2 × 10−4 S cm−1 and bulk conductivity of 1.72 × 10−3 S cm−1 at 700 °C. This study shows the promising potential of Zr-doped NaNbO3 as a solid electrolyte for various electrochemical applications.

Thermal-Sensitive Supramolecular Coordination Complex Formed by Orthogonal Metal Coordination and Host-Guest Interactions for an Electrical Thermometer.

Supramolecular coordination complexes (SCCs) are popular for their structural diversity and functional adaptability, which make them suitable for a wide range of applications. Photophysical and mechanical performance of SCCs are the most attractive characteristics, yet their ionically conductive behavior and potential in electrical sensing have been rarely investigated. This study reports a well-designed SCC that integrates orthogonal metal coordination and host-guest interactions to achieve sensitive electrical thermal sensing. Owing to the thermodynamic nature of the host-guest interaction, the SCC encounters thermally induced disassembly, leading to significantly enhanced ion mobility and thus allowing for the precise detection of minor temperature variation. The SCC-based thermometer is then fabricated with the assistance of 3D printing and demonstrates good accuracy and reliability in monitoring human skin temperature and real-time temperature changes of mouse during the whole anesthesia and recovery process. Our findings provide an innovative strategy for developing electrical thermometers and expand the current application scope of SCCs in electrical sensing.

Conformational Landscapes and Energetics of Carbon Nanohoops and their Ring-in-Ring Complexes.

Carbon nanohoops are promising precursors for the synthesis of nanotubes, whose structural dynamics are not well understood. Here, we investigate the conformational landscape and energetics of cycloparaphenylenes (CPPs), a methylene-bridged CPP and a carbon nanobelt. These nanohoops can form host-guest complexes with other rings, and understanding their structure is crucial for predicting their properties and identifying potential applications. We used a combination of ion mobility, tandem mass spectrometry, and density functional theory to characterize the nanohoops and their ring-in-ring complexes, following the energetics and conformations of their disassembly from intact complexes to fragment ions. Our results show structural integrity of the nanohoops and host-guest complexes. They also reveal interesting trends in size, packing density, stability, and structure between [6]CPP, the methylene-bridged CPP, and the carbon nanobelt as guests in ring-in-ring complexes. Taken together, our work illustrates how mass spectrometry data can help to unravel the rules that govern the formation of carbon nanohoop assemblies.

Elucidating the Gas-Phase Behavior of Nitazene Analog Protomers Using Structures for Lossless Ion Manipulations Ion Mobility-Orbitrap Mass Spectrometry.

2-Benzylbenzimidazoles, or "nitazenes", are a class of novel synthetic opioids (NSOs) that are increasingly being detected alongside fentanyl analogs and other opioids in drug overdose cases. Nitazenes can be 20× more potent than fentanyl but are not routinely tested for during postmortem or clinical toxicology drug screens; thus, their prevalence in drug overdose cases may be under-reported. Traditional analytical workflows utilizing liquid chromatography-tandem mass spectrometry (LC-MS/MS) often require additional confirmation with authentic reference standards to identify a novel nitazene. However, additional analytical measurements with ion mobility spectrometry (IMS) may provide a path toward reference-free identification, which would greatly accelerate NSO identification rates in toxicology laboratories. Presented here are the first IMS and collision cross section (CCS) measurements on a set of fourteen nitazene analogs using a structures for lossless ion manipulations (SLIM)-orbitrap MS. All nitazenes exhibited two high intensity baseline-separated IMS distributions, which fentanyls and other drug and druglike compounds also exhibit. Incorporating water into the electrospray ionization (ESI) solution caused the intensities of the higher mobility IMS distributions to increase and the intensities of the lower mobility IMS distributions to decrease. Nitazenes lacking a nitro group at the R1 position exhibited the greatest shifts in signal intensities due to water. Furthermore, IMS-MS/MS experiments showed that the higher mobility IMS distributions of all nitazenes possessing a triethylamine group produced fragment ions with m/z 72, 100, and other low intensity fragments while the lower mobility IMS distributions only produced fragment ions with m/z 72 and 100. The IMS, solvent, and fragmentation studies provide experimental evidence that nitazenes potentially exhibit three gas-phase protomers. The cyclic IMS capability of SLIM was also employed to partially resolve four sets of structurally similar nitazene isomers (e.g., protonitazene/isotonitazene, butonitazene/isobutonitazene/secbutonitazene), showcasing the potential of using high-resolution IMS separations in MS-based workflows for reference-free identification of emerging nitazenes and other NSOs.

Optical maneuvering of photofunctioning hybrid perovskite for future photonics potential application

Hybrid perovskites, known for their multidimensional opto-electronic properties and capability to generate multi-color emission bands, are highly sought after for light-emitting devices due to their liquid crystalline behavior in the solution phase. This behavior enables easier ion mobility, facilitating ion exchange processes. Exploiting the liquid crystalline properties of perovskites, we applied a halogen exchange reaction in the solution phase using tightly focused laser trapping techniques. Our study demonstrates the successful development of high-luminescent bulk single crystals of methylammonium lead halide alloy MAPb(Br/I)3, which exhibit multi-color emission capabilities, underscoring their potential for optoelectronic applications. We fabricated bulk single crystals of MAPbBr3, measuring 20 × 20 μm2, displaying bright green luminescence. Using a tightly focused trapping laser beam (1064 nm, 1 Watt) with a high numerical aperture (0.9, 60X objective lens), we irradiated a specific area of the green luminescent MAPbBr3 single crystal immersed in a 200 μM methylammonium iodide (MAI) solution for 30 min at room temperature. This treatment induced a red emission band at 605 nm at the irradiated location, while surrounding areas retained the original green luminescence. In a parallel experiment, increasing the iodide concentration to 300 μM caused the emission color of a similar-sized crystal to change uniformly from green to red. Photoluminescence spectroscopy and EDS confirmed the halide exchange from MAPbBr3 to MAPbBr2.3I0.7. This method, influenced by laser parameters such as power, wavelength, and aperture, provides new opportunities for multi-color emission patterning and offers significant insights for advancing optoelectronics.

µPhos: a scalable and sensitive platform for high-dimensional phosphoproteomics

Mass spectrometry has revolutionized cell signaling research by vastly simplifying the analysis of many thousands of phosphorylation sites in the human proteome. Defining the cellular response to perturbations is crucial for further illuminating the functionality of the phosphoproteome. Here we describe µPhos (‘microPhos’), an accessible phosphoproteomics platform that permits phosphopeptide enrichment from 96-well cell culture and small tissue amounts in <8 h total processing time. By greatly minimizing transfer steps and liquid volumes, we demonstrate increased sensitivity, >90% selectivity, and excellent quantitative reproducibility. Employing highly sensitive trapped ion mobility mass spectrometry, we quantify ~17,000 Class I phosphosites in a human cancer cell line using 20 µg starting material, and confidently localize ~6200 phosphosites from 1 µg. This depth covers key signaling pathways, rendering sample-limited applications and perturbation experiments with hundreds of samples viable. We employ µPhos to study drug- and time-dependent response signatures in a leukemia cell line, and by quantifying 30,000 Class I phosphosites in the mouse brain we reveal distinct spatial kinase activities in subregions of the hippocampal formation.

Rubidium ion incorporation: Suppression of halide ion diffusion in perovskite films

In recent years, organic-inorganic metal halide perovskite solar cells have made significant progress in energy conversion efficiency. However, their long-term stability and performance are often affected by the diffusion of halide ions within the perovskite structure. Inhibiting the migration of halide ions is very important to improve the operational stability and efficiency of solar cells. This study proposes a new method to characterize the diffusion of halide ions in perovskite films and demonstrates the effectiveness of incorporation of Rb+ into CsMAFA perovskite compositions. The addition of Rb+ reduces the concentration of mobile ions and the conductivity of ions in the perovskite film, thus eliminating the hysteresis phenomenon of perovskite solar cells. It is found that the efficiency and stability of the device are improved after optimization.

Ion Migration and Space‐Charge Zones in Metal Halide Perovskites Through Short‐Circuit Transient Current and Numerical Simulations

AbstractThe inherent ion migration in metal halide perovskite materials is known to induce deleterious and highly unstable dark currents in X‐ and γ‐ray detectors based on those compounds upon bias application. Dark current slow drift with time is identified as one of the major drawbacks for these devices to satisfy industrial requirements. Because dark current establishes the detectability limit, current evolution, and eventual growth may mask photocurrent signals produced by incoming X‐ray photons. Relevant information for detector assessment is ion‐related parameters such as ion concentration, ion mobility, and ionic space‐charge zones that are eventually built near the outer contacts upon detector biasing. A combined experimental (simple measurement of dark current transients) and 1D numerical simulation method is followed here using single‐crystal and microcrystalline millimeter‐thick methylammonium‐lead bromide that allows extracting ion mobility within the range of µion ≈ 10−7 cm2 V−1 s−1, while ion concentration values approximate Nion ≈ 1015 cm−3, depending on the perovskite crystallinity.

PVDF-HFP encapsulated WS2 nanosheets in droplet-based triboelectric nanogenerators for possible detection of human Na+/K+ ion concentration

Here we report the liquid–solid interaction in droplet-based triboelectric nanogenerators (TENG) for estimation of human Na+/K+ levels. The exploitation of PVDF-HFP encapsulated WS2 as active layer in the droplet-based TENG (DTENG) leads to the generation of electrical signal during the impact of water droplet. Comparison over the control devices indicates that surface quality and dielectric nature of the PVDF-HFP/WS2 composite largely dictates the performance of the DTENG. The demonstration of excellent sensitivity of the DTENG towards water quality indicates its promising application towards water testing. In addition, the alteration in output signal with slightest variation in ionic concentration (Na+ or K+) in water has been witnessed and is interpreted with charge transfer and ion transfer processes during liquid–solid interaction. The study reveals that the ion mobility largely affects the ion adsorption process on the active layer of PVDF-HFP/WS2 and thus generates distinct output profiles for diverse ions like Na+ and K+. Following that, the DTENG characteristics have been exploited to artificial urine where the varying output signals have been recorded for variation in urinary Na+ ion concentration. Therefore, the deployment of PVDF-HFP/WS2 in DTENG holds promising application towards the analyse of ionic characteristics of body fluids.

Carboxylated pillar[5]arene cavity accommodates organic cations in the host-guest complexes

The electron-rich cavity of carboxylated pillar[5]arene efficiently encapsulates cationic guest molecules within supramolecular assemblies. In this study we provide evidence of the host-guest complexation between carboxylated pillar[5]arene and benzamidine, a competitive inhibitor of serine proteases. We show the unexpected inclusion of the polar amidinium functionality within the central cavity of the macrocyclic host sustained by N+-H···π and cation···π interactions. In addition to the in-cavity complexation, simultaneous external binding of bipyridinium guests with varying stoichiometries has been observed. The interesting aspect is the inclusion of a hydrogen bonded pair of 1,2-bis(4-pyridyl)ethylene guests into pillar[5]arene cavity. Additional insights into inclusion characteristics are provided by NMR and ion mobility mass spectrometry (IM-MS) studies, offering information for the solution/gas phase and enabling a comprehensive description of the complexation process across different phases. This work expands the portfolio of cationic guest molecules capable of being encapsulated by carboxylated pillar[5]arene, showing new promises and directions for their inclusion and self-assembly behavior.

Enhancing Electrochemical Characteristics of Li‐Metal Electrodes: The Impact of Pre‐Treatment via CO2 Gas Reaction

AbstractRegulation of the surface film characteristics of Li‐metal is a pivotal strategy for augmenting the electrochemical performance of Li‐metal batteries. This investigation elucidates a straightforward approach to surface film modification, namely, pre‐treatment via a CO2 gas reaction, and its subsequent impact on the electrochemical attributes of Li‐metal electrodes. Analysis of the topography and composition of the Li metal surfaces revealed the transformation of the surface film into a more uniform layer enriched with inorganic compounds, including Li2CO3 and Li2O, by pre‐treatment. This pre‐treatment process significantly enhances the electrochemical properties, such as cyclability and overpotential, in Li/Li symmetric cells, primarily because of the formation of an improved solid‐electrolyte interphase (SEI) derived from the altered surface film on Li metal electrodes. The reformed SEI significantly increases the mobility of Li ions through the interphase, thereby attenuating the impedance associated with Li‐ion migration within the SEI. This resistance attenuation is instrumental in alleviating the overpotentials, thereby significantly refining the electrochemical plating and stripping dynamics of Li metal electrodes.

Differentiation of Cis/trans-geometrical isomers in long-chain unsaturated fatty acids based on ion mobility and theoretical calculations

In recent years, fatty acids containing conjugated CCs have attracted extensive research attention due to their biological activities against human diseases. However, their differentiation is challenging. This study developed a comprehensive analytical solution to accurately differentiate cis/trans-fatty acid isomers using ion mobility mass spectrometry (IM-MS) and theoretical calculations. Cis/trans-fatty acids were mobility-differentiated via simple complexation with 1,5,9-triazacyclododecane (9C3N) or 1,4,8,11-tetraazacyclotetradecane (10C4N) and metal ions, obtaining baseline separation with a peak-to-peak resolution of 0.35–0.92. Moreover, the conformation of the complexes was optimized theoretically, revealing different binding modes between the cis/trans-fatty acid-9C3N/10C4N–metal ion systems, yielding in-depth structural data on the complexes and elucidating the principles of mobility separation. Furthermore, the proposed method was assessed in terms of quantification, accuracy, and precision repeatability. Finally, the method was applied to analyze oil samples. Given its simplicity, speed, and lack of chemical derivatization or chromatographic separation, this technique has potential applications in food analysis.

Degradation of Anion Exchange Membranes by Cation Elimination: Impact on Water Uptake, Nanostructure, and Ionic Mobility

Degradation of Anion Exchange Membranes by Cation Elimination: Impact on Water Uptake, Nanostructure, and Ionic Mobility

Characteristics of changes in volatile organic compounds and bacterial communities in physically preserved pigeon breast meat

To understand the relationship between changes in aroma and bacteria in pigeon breast meat (PBM) during preservation, bacterial communities and volatile compounds in PBM were analyzed using high-throughput sequencing and gas chromatography–ion mobility spectrometry. Analyses of total viable bacteria counts revealed that modified atmospheric packaging (MAP) and electron beam irradiation (EBI) could be used to extend the shelf-life of PBM to 10 d and 15 d, respectively. Furthermore, Lactococcus spp. and Psychrobacter spp. were the dominant bacterial genera of the MAP and EBI groups, respectively. The results of the study revealed 91 volatile organic compounds, one of which, butanal, was the most intense volatile organic compound while being an important source of aroma differences between the physical preservation techniques. Alpha-terpinolene, acetoin-M, gamma-butyrolactone, 1-hexanol-M, and 2,6-dimethyl-4-heptanone may be markers of PBM spoilage. During preservation, the MA group (treatment with 50 % CO2 + 50 % N2) demonstrated greater stabilization of PBM aroma. A Spearman correlation analysis showed that Lactococcus spp., Psychrobacter spp., and Pseudomonas spp. were the dominant bacterial genera of PBM during preservation and were closely related to an increase in the intensity of anisole, 2-methyl-3-furanthiol, and 5-methyl-2-furanmethanol, respectively. Lactococcus spp. and Psychrobacter spp. play crucial roles in the sensory degradation of PBM. In this study, we analyzed the changes in bacterial genera and volatile organic compounds of PBM under different physical preservation techniques to identify a suitable method for preserving PBM and evaluating its freshness.

Radiation-Induced Molecular Processes in DNA: A Perspective on Gas-Phase Interaction Studies.

Studying the direct effects of DNA irradiation is essential for understanding the impact of radiation on biological systems. Gas-phase interactions are especially well suited to uncover the molecular mechanisms underlying these direct effects. Only relatively recently, isolated DNA oligonucleotides were irradiated by ionizing particles such as VUV or X-ray photons or ion beams, and ionic products were analyzed by mass spectrometry. This article provides a comprehensive review of primarily experimental investigations in this field over the past decade, emphasizing the description of processes such as ionization, fragmentation, charge and hydrogen transfer triggered by photoabsorption or ion collision, and the recent progress made thanks to specific atomic photoabsorption. Then, we outline ongoing experimental developments notably involving ion-mobility spectrometry, crossed beams or time-resolved measurements. The discussion extends to potential research directions for the future.

The History of the Development of Domestic Chemical Intelligence Tools

This article is dedicated to the history of the development of chemical reconnaissance and control means of the Workers' and Peasants' Red Army, the Soviet and Russian armies. This plot has never been covered previously in open literature. The aim of the work is to give a sketch of the development of chemical reconnaissance and control means from the First World War to the present day. The source base - documentary sources containing information about the chronology of acceptance for supply of chemical reconnaissance technical means, technical descriptions, manuals and operating instructions, as well as literature containing information about the design and principles of operation of these means. The method of analysis is descriptive. The discussion of the results. The most important factor that has influenced the development of means of indication was the development of chemical weapons. Аn analysis of information sources showed that before the Second World War, exclusively the chemical indication method was used. Since the late 1950s, due to the appearance of the organophosphorus agents, along with the chemical methods of indication, the biochemical methods began to be actively used both in military and in special means of chemical reconnaissance. The ionization method was first implemented in the early 1970s, the remote method (laser sensing) – in the late 1980s. Ion mobility spectrometry has been used since the late 1990s, gas chromatography-mass spectrometry and FT-IR spectroscopy – since the early 2000s. The technology of semiconductor sensors has been used in serial devices since the late 2000s. Conclusion. In general, the development of domestic chemical reconnaissance and control means goes in line with global trends. One of the modern trends is the development of combined devices based on a combination of several indication methods. Currently, the leading position is occupied by technical means of remote chemical reconnaissance and instruments, the operating principles of which are based on ion mobility spectrometry.