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Ion mobility spectrometry

Yinjuan Chen, Zhicheng Zuo, Xinhua Dai, Peng Xiao, Xiang Fang, Xuefeng Wang, Wenning Wang, Chuan-Fan Ding
Cyclodextrins (CDs) are a class of macrocyclic molecules that have exhibited many promising applications in various fields. The knowledge of the complexation modes and recognition mechanisms of CDs with their guests are of paramount importance for rational design of more variants with controlled properties. Herein we investigated the binding conformations and the structural characteristics of α-/β-CD with three amino acids (AA, AA=Gly, L-Leu, L-Phe) in the gas phase by a combined experimental and computational approach...
August 15, 2018: Talanta
Wolfgang Vautz, Joachim Franzke, Stefano Zampolli, Ivan Elmi, Sascha Liedtke
In this tutorial, we want to demonstrate the significant potential of ion mobility spectrometry (IMS), an analytical technique for identification and quantification of gas-phase compounds, in particular combined to other useful analytical tools. Coupled to gas-chromatographic pre-separation (GC-IMS), selectivity can be improved significantly, thus enabling the analysis of complex, humid mixtures. In-line pre-concentration can improve sensitivity down to the ppqV range. Furthermore, the use of non-radioactive ionisation sources in the near future could gain acceptance and will avoid legal restrictions...
September 18, 2018: Analytica Chimica Acta
Mohammad T Jafari, Mohammad Saraji, Mansoure Kermani
Carbon-silica hybrid nanofibers as high performance coatings for solid-phase microextraction fibers were used for analyzing some pesticides by using gas chromatography-corona discharge ion mobility spectrometry. To that end, the fibers were prepared by carbonizing sol-gel based on electrospun polyacrylonitrile and tetraethyl orthosilicate nanofibers as carbon and silica precursors, respectively. Different parameters affecting the electrospinning and the extraction processes including spinning distance, voltage, feeding rate, stirring rate, salt concentration, temperature and extraction time were optimized by response surface methodology...
May 8, 2018: Journal of Chromatography. A
Shubo Dong, Hanyue Yang, Deju Ye
A rapid and sensitive high-performance liquid chromatography-mass spectrometry method was developed and validated to determine 4-fluoroaniline concentration in ezetimibe. Chromatographic separation was achieved on a Phenomenex Gemini-NX C18 column (150 × 4.6 mm, 3 μm) maintained at 30°C. The liquid chromatography system was operated in gradient mode with an injection volume of 20 μL at a flow rate of 1 mL/min. Mobile phase A was water and mobile phase B consisted of acetonitrile with 0.05% acetic acid. The detection was performed using a single quadrupole mass spectrometer in single ion monitoring mode by using positive ionization...
May 14, 2018: Journal of Chromatographic Science
Proteinase pattern of honeybee prepupae from healthy and American Foulbrood infected bees investigated by zymography: The numbered spots (figure 4) were excised from the gels and they were individually transferred to a 1.5 mL microcentrifuge tube. Spots were destained and proteins digested as reported by Dani et al. 40. Each peptide mixture was submitted to capillary-LC-μESI-MS/MS analysis on an Ultimate 3000 HPLC (Dionex, San Donato Milanese, Milano, Italy) coupled to a LTQ Orbitrap mass spectrometer (Thermo Fisher, Bremen, Germany). Peptides were concentrated on a precolumn cartridge PepMap100 C18 (300 μm i.d. × 5 mm, 5 μm, 100 Å, LC Packings Dionex) and then eluted on a homemade capillary column packed with Aeris Peptide XB-C18 phase (180 μm i.d. × 15 cm, 3.6 μm, 100 Å, Phenomenex, Torrance, CA, USA) at 1 μl/min. The loading mobile phases were: 0.1% TFA in H 2 O (phase A) and 0.1% TFA in CH 3 CN (phase B). The elution mobile phases composition was: H 2 O 0.1% formic acid/CH 3 CN 97/3 (phase A) and CH 3 CN 0.1% formic acid/ H 2 O 97/3 (phase B). The elution program was: 0 min, 4% B; 10 min, 40% B; 30 min, 65% B; 35 min, 65% B; 36 min, 90% B; 40 min, 90% B; 41 min, 4%B; 60 min, 4% B. Mass spectra were acquired in positive ion mode, setting the spray voltage at 1.8 kV, the capillary voltage and temperature respectively at 45 V and 200°C, and the tube lens at 130 V. Data were acquired in data-dependent mode with dynamic exclusion enabled (repeat count 2, repeat duration 15 s, exclusion duration 30 s); survey MS scans were recorded in the Orbitrap analyzer in the mass range 300-2000 m/z at a 15,000 nominal resolution at m/z = 400; then up to three most intense ions in each full MS scan were fragmented (isolation width 3 m/z, normalized collision energy 30) and analyzed in the IT analyzer. Monocharged ions did not trigger MS/MS experiments.
Antonio Felicioli, Barbara Turchi, Filippo Fratini, Matteo Giusti, Roberta Nuvoloni, Francesca Romana Dani, Simona Sagona
American foulbrood disease (AFB) is the main devastating disease that affects honeybees' brood, caused by Paenibacillus larvae. The trend of the research on AFB has addressed the mechanisms by which P. larvae bacteria kill honeybee larvae. Since prepupae could react to the infection of AFB by increasing protease synthesis, the aim of this work was to compare protease activity in worker prepupae belonging to healthy colonies and to colonies affected by AFB. This investigation was performed by zymography. In gel, proteolytic activity was observed in prepupae extracts belonging to the healthy colonies...
May 15, 2018: Electrophoresis
Wolfgang Vautz, Chandrasekhara Hariharan, Maximilian Weigend
Plant volatile organic compounds (pVOCs) are being recognized as an important factor in plant-environment interactions. Both the type and amount of the emissions appear to be heavily affected by climate change. A range of studies therefore has been directed toward understanding pVOC emissions, mostly under laboratory conditions (branch/leaf enclosure). However, there is a lack of rapid, sensitive, and selective analytical methods, and therefore, only little is known about VOC emissions under natural, outdoor conditions...
May 2018: Ecology and Evolution
Natividad Jurado-Campos, Rocío Garrido-Delgado, Bruno Martínez-Haya, Gary A Eiceman, Lourdes Arce
Significant substances in emerging applications of ion mobility spectrometry such as breath analysis for clinical diagnostics and headspace analysis for food purity include low molar mass alcohols, ketones, aldehydes and esters which produce mobility spectra containing protonated monomers and proton-bound dimers. Spectra for all n- alcohols, aldehydes and ketones from carbon number three to eight exhibited protonated monomers and proton-bound dimers with ion drift times of 6.5-13.3 ms at ambient pressure and from 35° to 80 °C in nitrogen...
August 1, 2018: Talanta
Yasunori Watanabe, Snezana Vasiljevic, Joel D Allen, Gemma E Seabright, Helen Duyvesteyn, Katie J Doores, Max Crispin, Weston B Struwe
The development of domain-exchanged antibodies offers a route to high affinity targeting to clustered multivalent epitopes, such as those associated with viral infections and many cancers. One strategy to generate these antibodies is to introduce mutations into target antibodies to drive domain-exchange using the only known naturally-occurring domain-exchanged anti-HIV IgG1 antibody 2G12, as a template. Here, we show that domain-exchange can be sensitively monitored by ion-mobility mass spectrometry and gas-phase collision induced unfolding...
May 14, 2018: Analytical Chemistry
Lilian V Tose, Paolo Benigni, Dennys Leyva, Abigail Sundberg, César E Ramírez, Mark E Ridgeway, Melvin A Park, Wanderson Romão, Rudolf Jaffé, Francisco Fernandez-Lima
RATIONALE: There is a need for fast, post-ionization separation during the analysis of complex mixtures. In this study, we evaluate the use of a high-resolution mobility analyzer with high resolution and ultra-high-resolution mass spectrometry for unsupervised molecular feature detection. Goals include the study of the reproducibility of TIMS across platforms, applicability range and potential challenges during routine analysis. METHODS: A TIMS analyzer was coupled to TOF-MS and to an FT-ICR MS for the analysis of single charge species in the m/z 150-800 range of a complex mixture (Suwannee River Fulvic Acid Standard)...
May 14, 2018: Rapid Communications in Mass Spectrometry: RCM
Michael Nshanian, Rajeswari Lakshmanan, Hao Chen, Rachel R Ogorzalek Loo, Joseph A Loo
Trifluoroacetic acid (TFA) is often used as a mobile phase modifier to enhance reversed phase chromatographic performance. TFA adjusts solution pH and is an ion-pairing agent, but it is not typically suitable for electrospray ionization-mass spectrometry (ESI-MS) and liquid chromatography/MS (LC/MS) because of its significant signal suppression. Supercharging agents elevate peptide and protein charge states in ESI, increasing tandem MS (MS/MS) efficiency. Here, LC/MS protein supercharging was effected by adding agents to LC mobile phase solvents...
April 2018: International Journal of Mass Spectrometry
Ivana Blaženović, Tobias Kind, Jian Ji, Oliver Fiehn
The annotation of small molecules remains a major challenge in untargeted mass spectrometry-based metabolomics. We here critically discuss structured elucidation approaches and software that are designed to help during the annotation of unknown compounds. Only by elucidating unknown metabolites first is it possible to biologically interpret complex systems, to map compounds to pathways and to create reliable predictive metabolic models for translational and clinical research. These strategies include the construction and quality of tandem mass spectral databases such as the coalition of MassBank repositories and investigations of MS/MS matching confidence...
May 10, 2018: Metabolites
Michael Z Kamrath, Thomas R Rizzo
Ion mobility spectrometry (IMS) has become a valuable tool in biophysical and bioanalytical chemistry because of its ability to separate and characterize the structure of gas-phase biomolecular ions on the basis of their collisional cross section (CCS). Its importance has grown with the realization that in many cases, biomolecular ions retain important structural characteristics when produced in the gas phase by electrospray ionization (ESI). While a CCS can help distinguish between structures of radically different types, one cannot expect a single number to differentiate similar conformations of a complex molecule...
May 10, 2018: Accounts of Chemical Research
Ansgar Thomas Kirk, Tim Kobelt, Hauke Spehlbrink, Stefan Zimmermann
Corona discharge ionization sources are often used in ion mobility spectrometers (IMS) when a non-radioactive ion source with high ion currents is required. Typically, the corona discharge is followed by a reaction region where analyte ions are formed from the reactant ions. In this work, we present a simple yet sufficiently accurate model for predicting the ion current available at the end of this reaction region when operating at reduced pressure as in High Kinetic Energy Ion Mobility Spectrometers (HiKE-IMS) or most IMS-MS instruments...
May 8, 2018: Journal of the American Society for Mass Spectrometry
Guiyan Yuan, Huanjun Liu, Abdul S Shaikh, Rui Zhang, Pingli Li, Benjie Wang, Ruichen Guo
BACKGROUND: Therapeutic drug monitoring of vancomycin is very valuable due to the good correlation between trough levels and clinical outcome. Therefore, it is important to accurately determine the concentration of vancomycin in patient plasma for adequate dose-adjustment. The objective of this study was to develop a new liquid chromatography-mass spectrometry (LC-MS) method for determination of vancomycin in patient plasma and compare the results with those obtained from enzyme-multiplied immunoassay technique (EMIT)...
March 1, 2018: Clinical Laboratory
Andrey Dyachenko, Sem Tamara, Albert J R Heck
The GroES heptamer is the molecular co-chaperonin that partners with the tetradecamer chaperonin GroEL, which assists in the folding of various nonnative polypeptide chains in Escherichia coli. Gp31 is a structural and functional analogue of GroES encoded by the bacteriophage T4, becoming highly expressed in T4-infected E. coli, taking over the role of GroES, favoring the folding of bacteriophage proteins. Despite being slightly larger, gp31 is quite homologous to GroES in terms of its tertiary and quaternary structure, as well as in its function and mode of interaction with the chaperonin GroEL...
May 7, 2018: Journal of the American Society for Mass Spectrometry
Matteo T Degiacomi
Ion mobility mass spectrometry (IM/MS) can provide structural information on intact protein complexes. Such data, including connectivity and collision cross sections (CCS) of assemblies' subunits, can in turn be used as a guide to produce representative super coarse-grained models. These models are constituted by ensembles of overlapping spheres, each representing a protein subunit. A model is considered plausible if the CCS and sphere-overlap levels of its subunits fall within predetermined confidence intervals...
May 7, 2018: Journal of the American Society for Mass Spectrometry
Zhidan Chen, Stephen L Coy, Evan L Pannkuk, Evagelia C Laiakis, Albert J Fornace, Paul Vouros
High-throughput methods to assess radiation exposure are a priority due to concerns that include nuclear power accidents, the spread of nuclear weapon capability, and the risk of terrorist attacks. Metabolomics, the assessment of small molecules in an easily accessible sample, is the most recent method to be applied for the identification of biomarkers of the biological radiation response with a useful dose-response profile. Profiling for biomarker identification is frequently done using an LC-MS platform which has limited throughput due to the time-consuming nature of chromatography...
May 7, 2018: Journal of the American Society for Mass Spectrometry
Basri Gulbakan, Konstantin Barylyuk, Petra Schneider, Max Pillong, Gisbert Schneider, Renato Zenobi
Aptamers are oligonucleotide receptors obtained through an iterative selection process from random-sequence libraries. While many aptamers for a broad range of targets with high affinity and selectivity have been generated, a lack of high-resolution structural data and the limitations of currently available biophysical tools greatly impede understanding of the mechanisms of aptamer-ligand interactions. Here we demonstrate that an approach based on native electrospray ionization mass spectrometry (ESI-MS) can be successfully applied to characterize aptamer-ligand complexes in all details...
May 7, 2018: Journal of the American Chemical Society
Catalin Doneanu, Jing Fang, Yun Alelyunas, Ying Qing Yu, Mark Wrona, Weibin Chen
The analysis of low-level (1-100 ppm) protein impurities (e.g., host-cell proteins (HCPs)) in protein biotherapeutics is a challenging assay requiring high sensitivity and a wide dynamic range. Mass spectrometry-based quantification assays for proteins typically involve protein digestion followed by the selective reaction monitoring/multiple reaction monitoring (SRM/MRM) quantification of peptides using a low-resolution (Rs ~1,000) tandem quadrupole mass spectrometer. One of the limitations of this approach is the interference phenomenon observed when the peptide of interest has the "same" precursor and fragment mass (in terms of m/z values) as other co-eluting peptides present in the sample (within a 1-Da window)...
April 17, 2018: Journal of Visualized Experiments: JoVE
Takehito Inukai, Sanae Kaji, Hiroyuki Kataoka
Smoking not only increases the risk of lung cancer but is strongly related to the onset of cardiovascular disease. Particularly, passive smoking due to sidestream smoke is a critical public health problem. To assess active and passive exposure to tobacco smoke, we developed a simple and sensitive method, consisting of on-line in-tube solid phase microextraction (SPME) coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS), to determine nicotine and its metabolite cotinine in hair samples. These compounds were separated within 5 min using a Polar-RP80A column and detected in the positive ion mode by multiple reaction monitoring...
April 30, 2018: Journal of Pharmaceutical and Biomedical Analysis
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