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Analytical Chemistry

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https://www.readbyqxmd.com/read/28644622/single-analyzer-neutral-loss-scans-in-a-linear-quadrupole-ion-trap-using-orthogonal-double-resonance-excitation
#1
Dalton T Snyder, R Graham Cooks
In this follow-up paper to our previous work on single analyzer precursor ion scans in a linear quadrupole ion trap (Snyder, D. T.; Cooks, R. G.; "Single analyzer precursor ion scans in a linear quadrupole ion trap using orthogonal double resonance excitation", J. Am. Soc. Mass Spectrom. accepted), we now report the development of single analyzer neutral loss scans in a linear quadrupole ion trap using orthogonal double resonance excitation. Methodologically, there are three key differences between single analyzer precursor ion scans and neutral loss scans under constant radiofrequency (rf) conditions: 1) in the latter experiment both excitation and ejection frequencies must be scanned, whereas in the former the ejection frequency is fixed, 2) the need to maintain a constant neutral loss while incrementing both precursor and product ion masses - complicated by the complex relationship between secular frequency and mass - requires use of two simultaneous frequency scans, both linear in mass, and 3) because the ejection frequency is scanned, a third ac signal occurring between the ac excitation and ac ejection frequency scans must also be applied and scanned in order to reject artifact peaks caused by ejection of unfragmented precursor ions...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28644610/mzmine-2-data-preprocessing-to-enhance-molecular-networking-reliability
#2
Florent Olivon, Gwendal Grelier, Fanny Roussi, Marc Litaudon, David Touboul
Molecular networking is becoming more and more popular into the metabolomic community to organize tandem mass spectrometry (MS2) data. Even though this approach allows the treatment and comparison of large data sets, several drawbacks related to the MS-Cluster tool routinely used on the Global Natural Product Social Molecular Networking platform (GNPS) limit its potential. MS-Cluster cannot distinguish between chromatography well-resolved isomers as retention times are not taken into account. Annotation with predicted chemical formulas is also not implemented and semi-quantification is only based on the number of MS2 scans...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28644008/influence-of-tip-and-substrate-properties-and-nonsteady-state-effects-on-nanogap-kinetic-measurements-response-to-comment-on-impact-of-adsorption-on-scanning-electrochemical-microscopy-voltammetry-and-implications-for-nanogap-measurements
#3
https://www.readbyqxmd.com/read/28644005/from-electrochemistry-to-electroluminescence-development-and-application-in-ratiometric-aptasensor-for-aflatoxin-b1
#4
Long Wu, Fan Ding, Wenmin Yin, Jing Ma, Biru Wang, Axiu Nie, Heyou Han
Aflatoxin B1 (AFB1), one of the most toxic chemical carcinogens, has been widely studied. It remains challenging to develop simple, accurate and sensitive analytical methods for the detection of AFB1 in food matrices. In this work, based on dual-signaling strategy, a ratiometric aptasensor was designed and verified for the accurate and sensitive detection of AFB1. The electrochemical method was first used as a model to verify the specific interaction between AFB1 and the aptamer, in which ferrocene (Fc) and methylene blue (MB) anchored DNA sequences were acted as dual signals...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28644003/chemical-sensor-based-upon-stress-induced-changes-in-the-permeability-of-a-magnetoelastic-wire
#5
Nahla A Hatab, Nichole A Crane, David K Mee, L Neville Howell, Larry R Mooney, Russell L Hallman, Michael J Sepaniak, Vincent E Lamberti
We introduce a chemical sensing technology, named ChIMES (Chemical Identification through Magneto-Elastic Sensing), that can detect a broad range of targets and that has the capability of untethered communication through a metallic or nonmetallic barrier. These features enable many applications in which penetrations into the sampled environment are unwanted or infeasible because of health, safety, or environmental concerns, such as following the decomposition of a dangerous material in a sealed container. The sensing element is passive and consists of a target response material hard-coupled to a magnetoelastic wire...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28643517/a-novel-strategy-for-comprehensive-profiling-and-identification-of-acidic-glycosphingolipids-using-ultra-high-performance-liquid-chromatography-coupled-with-quadrupole-time-of-flight-mass-spectrometry
#6
Ting Hu, Zhixin Jia, Jinlan Zhang
Acidic glycosphingolipids (AGSLs), which mainly consist of ganglioside and sulfatide moieties, are highly concentrated in the central nervous system. Comprehensive profiling of AGSLs has historically been challenging because of their high complexity and the lack of standards. In this paper, a novel strategy was developed to comprehensively profile AGSLs using ultra-high-performance liquid chromatography-quadrupole time of flight mass spectrometry (UPLC-Q-TOF-MS). Ganglioside isomers with different glycan chains such as GD1a/ GD1b were completely separated on a C18 column for the first time to our knowledge, facilitated by the addition of formic acid in the mobile phase...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28643516/untargeted-comprehensive-two-dimensional-liquid-chromatography-coupled-with-high-resolution-mass-spectrometry-analysis-of-rice-metabolome-using-multivariate-curve-resolution
#7
Meritxell Navarro-Reig, Joaquim Jaumot, Anna Baglai, Gabriel Vivó-Truyols, Peter J Schoenmakers, Romà Tauler
In this work, a new strategy for the chemometric analysis of LC×LC-HRMS data is proposed. This approach consists of a preliminary compression step along the MS spectral dimension based on the selection of the Regions of Interest (ROI), followed by a further data compression along the chromatographic dimension by wavelet transforms. In a secondary step, the Multivariate Curve Resolution Alternating Least Squares (MCR-ALS) method is applied to previously compressed data sets obtained in the simultaneous analysis of multiple LC×LC-HRMS chromatographic runs from multiple samples...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28602085/implementation-of-online-preconcentration-and-microsecond-time-resolution-to-capillary-electrophoresis-single-particle-inductively-coupled-plasma-mass-spectrometry-ce-sp-icp-ms-and-its-application-in-silver-nanoparticle-analysis
#8
Darya Mozhayeva, Ingo Strenge, Carsten Engelhard
Capillary electrophoresis (CE) coupled to single particle inductively coupled plasma mass-spectrometry (SP-ICP-MS) was used for the first time with a prototype data acquisition (μsDAQ) system that features 5 μs time resolution (100% duty cycle) to separate and quantify mixtures of silver nanoparticles (Ag NPs). Additionally, an online preconcentration technique, reversed electrode polarity stacking mode (REPSM), was applied for Ag NPs analysis with CE-SP-ICP-MS for the first time. After optimization, best results were achieved using a injection time of 110 s and a constant pressure of 50 mbar in hydrodynamic injection mode...
June 23, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28641411/development-of-an-lc-hrms-metabolomics-method-with-high-specificity-for-metabolite-identification-using-all-ion-fragmentation-aif-acquisition
#9
Shama Naz, Hector Gallart-Ayala, Stacey Reinke, Caroline Mathon, Richard Blankley, Romanas Chaleckis, Craig Edward Wheelock
High-resolution mass spectrometry (HRMS)-based metabolomics approaches have made significant advances. However, metabolite identification is still a major challenge and significant bottleneck in translating metabolomics data into biological context. In the current study, a liquid chromatography (LC)-HRMS metabolomics method was developed using an all ion fragmentation (AIF) acquisition approach. In order to increase the specificity in metabolite annotation, four criteria were considered: i) accurate mass (AM), ii) retention time (RT), iii) MS/MS spectrum, and iv) product/precursor ion intensity ratios...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28641410/modeling-aquatic-toxicity-through-chromatographic-systems
#10
Alejandro Fernandez-Pumarega, Susana Amézqueta, Sandra Farré, Laura Muñoz-Pascual, Michael H Abraham, Elisabet Fuguet, Marti Roses
Environmental risk assessment requires information about the toxicity of the growing number of chemical products coming from different origins that can contaminate water and become toxicants to aquatic species or other living beings via the trophic chain. Direct toxicity measurements using sensitive aquatic species can be carried out but they may become expensive and ethically questionable. Literature refers to the use of chromatographic measurements that correlate to the toxic effect of a compound over a specific aquatic species as an alternative to get toxicity information...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640636/cross-reactive-synbody-affinity-ligands-for-capturing-diverse-noroviruses
#11
Nidhi Gupta, John C Lainson, Paul E Belcher, Luhui Shen, Hugh S Mason, Stephen Albert Johnston, Chris W Diehnelt
Noroviruses are the most common cause of acute gastroenteritis in the developed world. Noroviruses are a diverse group of nonenveloped RNA viruses that are continuously evolving. This leads to the rise of immunologically distinct strains of the same genotype on a frequent basis. This diversity presents a unique challenge for detection and tracking of new strains, with the continuous need for new norovirus affinity ligands. Our group developed a family of bivalent synbody affinity ligands using a virus-like particle (VLP) from the 2006 GII...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640594/biomedical-diagnostics-enabled-by-integrated-organic-and-printed-electronics
#12
Termeh Ahmadraji, Laura Gonzalez-Macia, Tapio Ritvonen, Andreas Willert, Saara Tuurala, Satu Ylimaula, David Donaghy, Mika Suhonen, Dave Smart, Vitaly Efremov, Aoife Morrin, Reinhard R Baumann, Munira Raja, Antti Kemppainen, Anthony J Killard
Organic and printed electronics integration has the potential to revolutionise many technologies, including biomedical diag-nostics. This work demonstrates the successful integration of multiple printed electronic functionalities into a single device capable of the measurement of hydrogen peroxide, and total cholesterol. The single-use device employed printed electrochemical sen-sors for hydrogen peroxide electroreduction integrated with printed electrochromic display and battery. The system was driven by a conventional electronic circuit designed to illustrate the complete integration of silicon ICs via pick and place, or using organic electronic circuits...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640589/ru-bpy-32-incorporated-luminescent-polymer-dots-double-enhanced-electrochemiluminescence-for-detection-of-single-nucleotide-polymorphism
#13
Yaqiang Feng, Feng Sun, Ningning Wang, Jianping Lei, Huangxian Ju
Encapsulating a large amount of electrochemiluminescence (ECL) active molecules into one nanoparticle for single target recognition can greatly improve the sensitivity of ECL assay. This work used luminescent conjugated polymer as a carrier to synthesize Ru(bpy)32+ doped polymer dots (RuPdots). The RuPdots with an average size of 20 nm and encapsulation of about 1354 Ru(bpy)32+ showed greatly enhanced ECL emission. Using tripropylamine as a co-reactant, the resonance energy transfer from the excited polymer dots to the encapsulated Ru(bpy)32+ was demonstrated, which led to 15...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640579/rapid-and-robust-quantification-of-p-xyleneselenocyanate-in-plasma-via-derivatization
#14
Wenyi Zheng, Fadwa Benkessou, Brigitte Twelkmeyer, Siyao Wang, Tobias Ginman, Håkan Ottosson, Manuchehr Abedi-Valugerdi, Maria Angels Subirana, Ying Zhao, Moustapha Hassan
p-Xyleneselenocyanate (p-XSC) is one of the most investigated selenium compounds in cancer-prevention and -therapy. Despite the potent anti-cancer property, there is still no proper method to perform the quantitative analysis of p-XSC in plasma. In this investigation, we aimed at developing a method based on liquid chromatography-mass spectrometry (LC-MS) for the measurement of p-XSC in plasma. Direct deproteinization was first used to extract parent p-XSC from plasma, but failed to achieve high recovery rate (< 2%) due to formation of selenium-sulfur bond between p-XSC and plasma protein...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28640577/laser-ablation-molecular-isotopic-spectrometry-for-molecules-formation-chemistry-in-fs-laser-ablated-plasmas
#15
Huaming Hou, Xianglei Mao, Vassilia Zorba, Richard E Russo
Recently, laser ablated molecular isotopic spectrometry (LAMIS) has expanded its capability to explore molecules formation mechanism in laser induced plasma in addition to isotope analysis. LAMIS is powerful tool for tracking the origination of atoms that involved in formation of investigated molecules by labeling atoms with its isotopic substitution. The evolutionary formation pathways of organic molecules, especially of C2 dimers and CN radicals, were frequently reported. However, very little is known about the formation pathways for metallic radicals and heterodimers in laser ablated plasma...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28635252/proton-fueled-reversible-dna-hybridization-chain-assembly-for-ph-sensing-and-imaging
#16
Lan Liu, Jin-Wen Liu, Zhi-Mei Huang, Han Wu, Na Li, Li-Juan Tang, Jian-Hui Jiang
Design of DNA self-assembly with reversible responsiveness to external stimuli is of great interest for diverse applications. We for the first time develop a pH-responsive, fully reversible hybridization chain reaction (HCR) assembly that allows sensitive sensing and imaging of pH in living cells. Our design relies on the triplex forming sequences that form DNA triplex with toehold regions under acidic conditions and then induce a cascade of strand displacement and DNA assembly. The HCR assembly has shown dynamic responses in physiological pH ranges with excellent reversibility and demonstrated the potential for in vitro detection and live-cell imaging of pH...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28631479/quantitative-analysis-of-ligand-induced-heterodimerization-of-two-distinct-receptors
#17
Chang Lu, Zhi-Xin Wang
The induced dimerization of two distinct receptors through a heterobifunctional inducer is prevalent among all levels of cellular signaling processes, yet its complexity poses difficulty for systematic quantitative analysis. This paper first shows how to calculate the amount of any possible complex or monomer of heteroligand and two receptors present at equilibrium. The theory is subsequently applied to the determination of three independent equilibrium parameters involved in the rapamycin induced FKBP and FRB dimerization, in which all parameters were simultaneously estimated using one set of fluorescence resonance energy transfer (FRET) experiments...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28603959/characterization-of-complex-polymer-self-assemblies-and-large-aggregates-by-multidetector-thermal-field-flow-fractionation
#18
Upenyu L Muza, Guilaume Greyling, Harald Pasch
Micelles prepared from amphiphilic block copolymers (ABCs) have found numerous applications in pharmaceutical, electronics, environmental, cosmetics, and hygiene industries. These micelles, whether in the pure or mixed micelle form, often exist as multiple morphologies (spherical, cylindrical, worm, or vesicular) in equilibrium with each other. However, none of the current column-based fractionation techniques or any microscopic technique are capable of a successful separation, identification, and quantitation of these complex self-assemblies with regards to morphology, size, molar mass, and chemical composition in one experiment...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28561584/in-situ-detection-and-imaging-of-telomerase-activity-in-cancer-cell-lines-via-disassembly-of-plasmonic-core-satellites-nanostructured-probe
#19
Kan Wang, Li Shangguan, Yuanjian Liu, Ling Jiang, Fen Zhang, Yuanqing Wei, Yuanjian Zhang, Zhengjian Qi, Kang Wang, Songqin Liu
The label-free localized surface plasmon resonance (LSPR) detection technique has been identified as a powerful means for in situ investigation of biological processes and localized chemical reactions at single particle level with high spatial and temporal resolution. Herein, a core-satellites assembled nanostructure of Au50@Au13 was designed for in situ detection and intracellular imaging of telomerase activity by combining plasmonic resonance Rayleigh scattering spectroscopy with dark-field microscope (DFM)...
June 22, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28540721/resonant-gravimetric-identification-of-competitive-adsorption-of-environmental-molecules
#20
Pengcheng Xu, Tao Xu, Haitao Yu, Xinxin Li
Understanding competitive adsorption relationship among various ambient gases is important in adsorbing-material development for capturing environmentally harmful gas. For example, environmental interfering factors (e.g., moisture) can affect the competitive gas-molecule adsorption that needs to be clarified. Due to a lack of method to quantitatively study the dynamic adsorbing process (e.g., real-time-counting adsorbed molecule number), it is difficult to reveal the competitive adsorption mechanism. Still using conventional "trial-and-error" method hinders the development of high-performance adsorbing materials; thereby new technology is in high demand to address the issue...
June 22, 2017: Analytical Chemistry
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