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Secondary ion mass spectrometry

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https://www.readbyqxmd.com/read/28731678/stable-and-efficient-cuo-based-photocathode-through-oxygen-rich-composition-and-au-pd-nanostructure-incorporation-for-solar-hydrogen-production
#1
Saeid Masudy-Panah, Roozbeh Siavash Moakhar, Chin Sheng Chua, Ajay Kumar Kushwaha, Goutam Kumar Dalapati
Enhancing stability against photo-corrosion and improving photocurrent response are the main challenges toward the development of cupric oxide (CuO) based photocathodes for solar-driven hydrogen production. In this paper, stable and efficient CuO-photocathodes have been developed using in-situ materials engineering and through gold-palladium (Au-Pd) nanoparticles deposition on the CuO surface. The CuO photocathode exhibits a photocurrent generation of ~3 mA/cm2 at 0V v/s RHE. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analysis and X-ray spectroscopy (XPS) confirm the formation of oxygen-rich (O-rich) CuO film which demonstrate highly stable photocathode with retained photocurrent of ~90% for 20 minutes...
July 21, 2017: ACS Applied Materials & Interfaces
https://www.readbyqxmd.com/read/28729560/adaptive-control-of-ion-yield-in-femtosecond-laser-post-ionization-for-secondary-ion-mass-spectrometry
#2
Dusan Lorenc, Monika Jerigova, Monika Stupavska, Dusan Velic
Secondary ion mass spectrometry is an excellent technique of analytical chemistry, where primary ions sputter a solid sample generating the secondary ions which are determined. Although the ion yield is inherently low, it can be enhanced by using a post-ionization of sputtered neutral species. Our novel approach integrates this technique with a near infrared femtosecond laser post-ionization based on an adaptive control through a laser pulse shaper. The shaping of the laser pulse provides adaptive control to select a mass peak of interest and to enhance this peak intensity...
July 20, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28725003/distribution-of-salicifoline-in-freeze-fixed-stems-of-magnolia-kobus-as-observed-by-cryo-tof-sims
#3
Wakaba Okumura, Dan Aoki, Yasuyuki Matsushita, Masato Yoshida, Kazuhiko Fukushima
Alkaloids are basic nitrogen-containing chemicals that have important physiological and pharmacological characteristics. Many vascular plant species contain alkaloids, and their roles in planta are of interest. However, the detailed distribution of alkaloids remains unclear because of their low water solubility and low concentrations in plants. In this study, we visualized the distribution of salicifoline, a water-soluble quaternary ammonium alkaloid, in the freeze-fixed stems of Magnolia kobus by cryo time-of-flight secondary ion mass spectrometry...
July 19, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28722812/chemical-profile-of-pineapple-cv-vit%C3%A3-ria-in-different-maturation-stages-using-electrospray-ionization-mass-spectrometry
#4
Elizângela M Ogawa, Helber B Costa, José A Ventura, Luiz C S Caetano, Fernanda E Pinto, Bruno G Oliveira, Maria Eduarda S Barroso, Rodrigo Scherer, Denise C Endringer, Wanderson Romão
BACKGROUND: Pineapple is the fruit of Ananas comosus var. comosus plant, being cultivated in tropical areas and has high energy content and nutritional value. Herein, 30 samples of pineapple cv. Vitória were analyzed as a function of the maturation stage (0-5) and their physicochemical parameters monitored. Besides, negative-ion mode electrospray ionization mass spectrometry (ESI(-)FT-ICR MS) was used to identify and semi-quantify primary and secondary metabolites present in the crude and phenolic extracts of pineapple, respectively...
July 19, 2017: Journal of the Science of Food and Agriculture
https://www.readbyqxmd.com/read/28700825/chemical-visualization-of-sweat-pores-in-fingerprints-using-go-enhanced-tof-sims
#5
Lesi Cai, Mengchan Xia, Zhaoying Wang, Ya-Bin Zhao, Zhanping Li, Sichun Zhang, Xinrong Zhang
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) has been used in imaging of small molecules (< 500 Da) in fingerprints, such as gunshot residues and illicit drugs. However, identifying and mapping relatively high mass molecules are quite difficult owing to insufficient ion yield of their molecular ions. In this report, Graphene oxide(GO)-enhanced TOF-SIMS was used to detect and image relatively high mass molecules such as poison, alkaloids (> 600 Da) and controlled drugs, antibiotics (> 700 Da) in fingerprints...
July 12, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28698654/megapixel-multi-elemental-imaging-by-laser-induced-breakdown-spectroscopy-a-technology-with-considerable-potential-for-paleoclimate-studies
#6
J O Cáceres, F Pelascini, V Motto-Ros, S Moncayo, F Trichard, G Panczer, A Marín-Roldán, J A Cruz, I Coronado, J Martín-Chivelet
Paleoclimate studies play a crucial role in understanding past and future climates and their environmental impacts. Current methodologies for performing highly sensitive elemental analysis at micrometre spatial resolutions are restricted to the use of complex and/or not easily applied techniques, such as synchrotron radiation X-ray fluorescence micro-analysis (μ-SRXRF), nano secondary ion mass spectrometry (nano-SIMS) or laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Moreover, the analysis of large samples (>few cm²) with any of these methods remains very challenging due to their relatively low acquisition speed (~1-10 Hz), and because they must be operated in vacuum or controlled atmosphere...
July 11, 2017: Scientific Reports
https://www.readbyqxmd.com/read/28696656/distinct-chemical-and-physical-properties-of-janus-nanosheets
#7
Al C de Leon, Bradley J Rodier, Qinmo Luo, Christina M Hemmingsen, Peiran Wei, Kevin Abbasi, Rigoberto Advincula, Emily B Pentzer
Janus particles have recently garnered significant attention for their distinct properties compared to particles that are homogeneously functionalized. Moreover, high aspect ratio Janus particles that are rod-like or planar (i.e., nanosheets) are especially intriguing considering their interfacial properties, as well as their ability to assemble into higher order and hybrid structures. To date, major challenges facing the exploration and utilization of 2D Janus particles are scalability of synthesis, characterization of tailored chemical functionalization, and ability to introduce a diverse set of functionalities...
July 11, 2017: ACS Nano
https://www.readbyqxmd.com/read/28681076/a-multiresidue-method-for-the-analysis-of-90-pesticides-16-pahs-and-22-pcbs-in-honey-using-quechers-spme
#8
Josephine Al-Alam, Ziad Fajloun, Asma Chbani, Maurice Millet
An optimized analytical method was developed for the simultaneous analysis of 90 pesticides, 16 polycyclic aromatic hydrocarbons, and 22 polychlorinated biphenyls. The method was based on quick, easy, cheap, effective, rugged, and safe (QuEChERS) extraction using acetonitrile followed by a dispersive solid-phase extraction cleanup using primary-secondary amine and octadecyl (C18). The extract obtained was concentrated by evaporation and then reconstituted with acetonitrile to prepare it for chromatographic analysis by liquid chromatography-triple-quadrupole tandem mass spectrometry and gas chromatography-ion-trap tandem mass spectrometry, which was preceded by a preconcentration step using solid-phase microextraction with appropriate fibers...
July 5, 2017: Analytical and Bioanalytical Chemistry
https://www.readbyqxmd.com/read/28664967/two-coexisting-liquid-phases-in-switchable-ionic-liquids
#9
Juan Yao, David B Lao, Xiao Sui, Yufan Zhou, Satish K Nune, Xiang Ma, Tyler P Troy, Musa Ahmed, Zihua Zhu, David J Heldebrant, Xiao-Ying Yu
Switchable ionic liquids (SWILs) derived from organic bases and alcohols are attractive due to their applications in gas capture, separations, and nanomaterial synthesis. However, their exact solvent structure still remains a mystery. We present the first chemical mapping of a SWIL solvent structure using in situ time-of-flight secondary ion mass spectrometry. In situ chemical mapping discovers two coexisting liquid phases and molecular structures vastly different from conventional ionic liquids. SWIL chemical speciation is found to be more complex than the known stoichiometry...
June 30, 2017: Physical Chemistry Chemical Physics: PCCP
https://www.readbyqxmd.com/read/28664170/data-on-tof-sims-analysis-of-cu-2-co-2-and-cr-3-doped-calcium-phosphate-cements
#10
Anja Henß, Martha Schamel, Uwe Gbureck, Michael Gelinsky, Anja Lode
This article contains data of time of flight secondary ion mass spectrometry (TOF-SIMS) analysis of brushite-forming calcium phosphate cements doped with biologically active metal ions. This data are related to the research article "Cu(2+), Co(2+) and Cr(3+) doping of a calcium phosphate cement influences materials properties and response of human mesenchymal stromal cells" (Schamel et al., 2017) [1]. Cu(2+), Co(2+) and Cr(3+) doped β-tricalcium phosphate precursor powders were used to prepare cement samples...
August 2017: Data in Brief
https://www.readbyqxmd.com/read/28660065/micrometre-and-nanometre-scale-patterning-of-binary-polymer-brushes-supported-lipid-bilayers-and-proteins
#11
Alexander Johnson, Jeppe Madsen, Paul Chapman, Abdullah Alswieleh, Omed Al-Jaf, Peng Bao, Claire R Hurley, Michaël L Cartron, Stephen D Evans, Jamie K Hobbs, C Neil Hunter, Steven P Armes, Graham J Leggett
Binary polymer brush patterns were fabricated via photodeprotection of an aminosilane with a photo-cleavable nitrophenyl protecting group. UV exposure of the silane film through a mask yields micrometre-scale amine-terminated regions that can be derivatised to incorporate a bromine initiator to facilitate polymer brush growth via atom transfer radical polymerisation (ATRP). Atomic force microscopy (AFM) and imaging secondary ion mass spectrometry (SIMS) confirm that relatively thick brushes can be grown with high spatial confinement...
June 1, 2017: Chemical Science
https://www.readbyqxmd.com/read/28655664/protection-of-hydrophobic-amino-acids-against-moisture-induced-deterioration-in-the-aerosolization-performance-of-highly-hygroscopic-spray-dried-powders
#12
Jiaqi Yu, Hak-Kim Chan, Thomas Gengenbach, John A Denman
BACKGROUND: Inhalable particles containing amorphous form of drugs or excipients may absorb atmospheric moisture, causing powder aggregation and recrystallization, adversely affecting powder dispersion and lung deposition. The present study aims to explore hydrophobic amino acids for protection against moisture in spray-dried amorphous powders, using disodium cromoglycate (DSCG) as a model drug. MATERIALS AND METHODS: DSCG powders were produced by co-spray drying with isoleucine (Ile), valine (Val) and methionine (Met) in various concentrations (10, 20 and 40% w/w)...
June 24, 2017: European Journal of Pharmaceutics and Biopharmaceutics
https://www.readbyqxmd.com/read/28642031/clustering-of-ms-2-spectra-using-unsupervised-methods-to-aid-the-identification-of-secondary-metabolites-from-pseudomonas-aeruginosa
#13
Tobias Depke, Raimo Franke, Mark Brönstrup
Pseudomonas aeruginosa is an important opportunistic pathogen that produces a large arsenal of small molecule virulence factors and quorum sensing signal molecules. The annotation of these secondary metabolites in untargeted, mass spectrometry-based metabolomics is difficult, as many of them cannot be found in common metabolite databases, and as manual annotation is tedious. We therefore developed an algorithm named CluMSID that uses cosine similarities of product ion spectra and neutral loss patterns in combination with unsupervised clustering methods such as multidimensional scaling, density based clustering and hierarchical clustering to group structurally similar compounds and hence facilitate their annotation...
June 4, 2017: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
https://www.readbyqxmd.com/read/28633407/exploring-fungus-plant-n-transfer-in-a-tripartite-ant-plant-fungus-mutualism
#14
Céline Leroy, Alain Jauneau, Yves Martinez, Armelle Cabin-Flaman, David Gibouin, Jérôme Orivel, Nathalie Séjalon-Delmas
Background and Aims: The plant Hirtella physophora , the ant Allomerus decemarticulatus and a fungus, Trimmatostroma sp., form a tripartite association. The ants manipulate both the plant trichomes and the fungus to build galleries under the stems of their host plant used to capture prey. In addition to its structural role, the fungus also improves nutrient uptake by the host plant. But it still remains unclear whether the fungus plays an indirect or a direct role in transferring nutrients to the plant...
June 13, 2017: Annals of Botany
https://www.readbyqxmd.com/read/28630783/highly-sensitive-colorimetric-assay-for-determining-fe-3-based-on-gold-nanoparticles-conjugated-with-glycol-chitosan
#15
Kyungmin Kim, Yun-Sik Nam, Yeonhee Lee, Kang-Bong Lee
A highly sensitive and simple colorimetric assay for the detection of Fe(3+) ions was developed using gold nanoparticles (AuNPs) conjugated with glycol chitosan (GC). The Fe(3+) ion coordinates with the oxygen atoms of GC in a hexadentate manner (O-Fe(3+)-O), decreasing the interparticle distance and inducing aggregation. Time-of-flight secondary ion mass spectrometry showed that the bound Fe(3+) was coordinated to the oxygen atoms of the ethylene glycol in GC, which resulted in a significant color change from light red to dark midnight blue due to aggregation...
2017: Journal of Analytical Methods in Chemistry
https://www.readbyqxmd.com/read/28626281/measurement-of-uranium-236-in-particles-by-secondary-ion-mass-spectrometry
#16
David S Simons, John D Fassett
The determination of the relative isotopic abundance by secondary ion mass spectrometry of (236)U in uranium-containing material is complicated by the presence of (235)U(1)H(+) ions at the same nominal mass as the uranium isotopic peak. The net intensity of the (236)U signal is usually determined by a peak-stripping procedure, whereby the (235)U(1)H(+) contribution is obtained by applying the (238)U(1)H(+)/(238)U(+) ratio to the (235)U(+) signal. The subtraction of one signal from another has consequences for the uncertainty of the final (236)U abundance determination that may be especially significant when the amount of sample is limited, as is the case with small uranium particles that are of great interest for nuclear safeguards...
February 2017: Journal of Analytical Atomic Spectrometry
https://www.readbyqxmd.com/read/28623701/transition-temperature-of-poly-methyl-methacrylate-determined-by-time-of-flight-secondary-ion-mass-spectrometry-and-contact-angle-measurements
#17
Yi Fu, Yiu-Ting R Lau, Lu-Tao Weng, Kai-Mo Ng, Chi-Ming Chan
The surface chain conformations of poly(methyl methacrylate) (PMMA) at different temperatures were extensively studied by time-of-flight secondary ion mass spectrometry (ToF-SIMS). Similar to our previous experimental studies on polystyrene (PS) and poly(2, 3, 4, 5, 6-pentafluorostyrene) (5FPS), a transition temperature (TT) could be identified through the principal component analysis (PCA) of the ToF-SIMS spectra obtained from the PMMA samples annealed at different temperatures. Interestingly, our results show that the TT depended on molecular weight and was about 50-60˚C below the bulk glass transition temperature (Tg) and therefore could possibly be related to the surface glass transition temperature (Tg(S))...
June 1, 2017: Journal of Colloid and Interface Science
https://www.readbyqxmd.com/read/28617583/tof-sims-depth-profiling-of-ps-b-pmma-block-copolymers-using-arn-c60-and-cs-sputtering-ions
#18
T Terlier, G Zappalà, C Marie, D Leonard, J-P Barnes, A Licciardello
Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a high performance tool for molecular depth profiling of polymer films, in particular when they are structured in microphases. However, a major issue is the degradation of polymer materials under ion irradiation in reactions such as cross-linking, chain breaking, or reorganization processes of polymers which have been demonstrated for materials such as polystyrene (PS) and poly(methyl methacrylate) (PMMA). This work aims at comparing ToF-SIMS molecular depth profiling of structured polymers (polystyrene (PS)-b-polymethyl methacrylate (PMMA) block copolymers (BCP)) using either ultralow energy cesium or the more recently introduced C60(++) (under NO dosing and with sample cooling) and argon cluster ion beams (using Ar1500(+) ions at 5 keV)...
June 15, 2017: Analytical Chemistry
https://www.readbyqxmd.com/read/28614950/grafting-of-architecture-controlled-poly-styrene-sodium-sulfonate-onto-titanium-surfaces-using-bio-adhesive-molecules-surface-characterization-and-biological-properties
#19
Hamza Chouirfa, Margaret D M Evans, David G Castner, Penny Bean, Dimitri Mercier, Anouk Galtayries, Céline Falentin-Daudré, Véronique Migonney
This contribution reports on grafting of bioactive polymers such as poly(sodium styrene sulfonate) (polyNaSS) onto titanium (Ti) surfaces. This grafting process uses a modified dopamine as an anchor molecule to link polyNaSS to the Ti surface. The grafting process combines reversible addition-fragmentation chain transfer polymerization, postpolymerization modification, and thiol-ene chemistry. The first step in the process is to synthetize architecture controlled polyNaSS with a thiol end group. The second step is the adhesion of the dopamine acrylamide (DA) anchor onto the Ti surfaces...
June 14, 2017: Biointerphases
https://www.readbyqxmd.com/read/28612342/effect-of-glycine-nitrogen-on-lettuce-growth-under-soilless-culture-a-metabolomics-approach-to-identify-the-main-changes-occurred-in-plant-primary-and-secondary-metabolism
#20
Xiao Yang, Lei Feng, Li Zhao, Xiaosong Liu, Danial Hassani, Danfeng Huang
BACKGROUND: Lettuce is a significant source of antioxidants and bioactive compounds. Nitrate is a cardinal fertilizer in horticulture and influences vegetable yield and quality; however, the negative effects of nitrate on the biosynthesis of flavonoids require further study. It is expected that using fertilizers containing organic N could promote the synthesis of health-promoting compounds. RESULTS: Lettuces were hydroponically cultured in media containing 9 mM nitrate or 9 mM glycine for 4 weeks...
June 14, 2017: Journal of the Science of Food and Agriculture
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