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Secondary ion mass spectrometry

Jiale Huang, Langjun Zhou, Zhiqing Xun, Qiang Wang, Senyu Lin, Xindong Guo, Yongtong Cai
An analytical method was established for the simultaneous determination of seven nitrogen-containing phenyl ethers (2-anisidine, 3-anisidine, 4-anisidine, 2-nitroanisole, 3-nitroanisole, 4-nitroanisole and 3,3'-dimethoxybenzidine) in cosmetics by gas chromatography with mass spectrometry in this work. The samples were extracted with ethyl acetate and purified with primary secondary amine during the dispersed solid phase extraction. The analytes were separated by a DB-17MS column and detected in the electron ionization mode of mass spectrometry in the selected ions monitoring mode...
February 23, 2017: Journal of Separation Science
Miyeon Lee, Arup Kumer Roy, Seongho Jo, Yujin Choi, Ari Chae, Bongsoo Kim, Sung Yong Park, Insik In
We report the characterization and formation of sonication-assisted liquid phase exfoliation of bulk black phosphorus (BP) crystals with the incorporation of two representative ionic liquids (ILs) ([Emim][Tf2N] and [Bmim][Tf2N]) as green dispersing media was attempted, which resulted in stable dispersion of multi-layer BP flakes with unsuspected high oxidation resistance and chemical/structural integrity due to the presence of IL layer on top of BP flakes. There are two unveiled issues for the generation of BP dispersion in ILs...
February 21, 2017: Nanotechnology
Ju-Hee Im, Hong-Rae Kim, Byoung-Gi An, Young Wook Chang, Min-Jung Kang, Tae-Geol Lee, Jin Gyeng Son, Jae-Gwan Park, Jae-Chul Pyun
The direct in situ synthesis of cadmium sulfide (CdS) nanowires (NWs) was presented by direct synthesis of CdS NWs on the gold surface of an interdigitated electrode (IDE). In this work, we investigated the effect of a strong oxidant on the surfaces of the CdS NWs using X-ray photoelectron spectroscopy, transmission electron microscopy, and time-of-flight secondary ion mass spectrometry. We also fabricated a parylene-C film as a surface passivation layer for in situ-synthesized CdS NW photosensors and investigated the influence of the parylene-C passivation layer on the photoresponse during the coating of parylene-C under vacuum using a quartz crystal microbalance and a photoanalyzer...
February 16, 2017: Biosensors & Bioelectronics
Annabel Braem, Katrijn De Brucker, Nicolas Delattin, Manuela Sonja Killian, Maarten B J Roeffaers, Tomohiko Yoshioka, Satoshi Hayakawa, Patrik Schmuki, Bruno P A Cammue, Sannakaisa Virtanen, Karin Thevissen, Bram Neirinck
One prominent cause of implant failure is infection, therefore research is focusing on developing surface coatings that render the surface resistant to colonization by micro-organisms. Permanently attached coatings of antimicrobial molecules are of particular interest because of the reduced cytoxicity and lower risk of developing resistance compared to controlled release coatings. In this study, we focus on the chemical grafting of bioactive molecules on titanium. To concentrate the molecules at the metallic implant surface, we propose electrophoretic deposition (EPD) applying alternating current (AC) signals with an asymmetrical wave shape...
February 17, 2017: ACS Applied Materials & Interfaces
Hyeonseok Yoo, Alexander Welle, Wei Guo, Jinsub Choi, Engelbert Redel
We describe a novel procedure to fabricate WO3@surface-mounted metal-organic framework (SURMOF) hybrid materials by electrodeposition of WO3 nanoparticles into HKUST-1, also termed Cu3(BTC)2 SURMOFs. These materials have been characterized using x-ray diffraction, time-of-flight secondary ion mass spectrometry, scanning electron microscopy, x-ray photoelectron spectroscopy as well as linear sweep voltammetry. The WO3 semiconductor/SURMOF heterostructures were further tested as hybrid electrodes in their performance for hydrogen evolution reaction from water...
March 17, 2017: Nanotechnology
P J Chen, M Zhu, S Tibus, T Dyer, J Piccirillo, B Ocker, R D Shull
A full Co20Fe60B20\MgO\ Co20Fe60B20 perpendicular magnetic tunnel junction (pMTJ) with (Co\Pt) multilayers as pinning layers and different functional multilayers stacks were made and annealed at different temperatures. The tunneling magnetoresistance ratio (TMR) and MgO barrier resistance-area product (RA) were measured and analyzed as a function of annealing temperature. The TMR of pMTJs dramatically declines with increasing annealing temperatures from 320 °C to 400 °C while the RA increases with temperature from 375 °C to 450 °C...
January 18, 2017: Journal of Physics D: Applied Physics
Patrick Rupper, Marianne Vandenbossche, Laetitia Bernard, Dirk Hegemann, Manfred Heuberger
Controlling the balance between stability and functional group density in grown plasma polymer films is the key to diverse applications such as drug release, tissue-engineered implants, filtration, contact lenses, microfluidics, electrodes, sensors, etc. Highly functional plasma polymer films typically show a limited stability in air or aqueous environments due to mechanisms like molecular reorganization, oxidation, and hydrolysis. Stabilization is achieved by enhancing cross-linking at the cost of the terminal functional groups such as -OH and -COOH, but also -NH2, etc...
February 21, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Thanh D Do, Troy J Comi, Sage J B Dunham, Stanislav S Rubakhin, Jonathan V Sweedler
A high-throughput single cell profiling method has been developed for matrix-enhanced-secondary ion mass spectrometry (ME-SIMS) to investigate the lipid profiles of neuronal cells. Populations of cells are dispersed onto the substrate, their locations determined using optical microscopy, and the cell locations used to guide the acquisition of SIMS spectra from the cells. Up to 2,000 cells can be assayed in one experiment at a rate of 6 s per cell. Multiple saturated and unsaturated phosphatidylcholines (PCs) and their fragments are detected and verified with tandem mass spectrometry from individual cells when ionic liquids are employed as a matrix...
February 10, 2017: Analytical Chemistry
Lu Huang, Yin Chen, Lu-Tao Weng, Mark Leung, Xiaoxing Xing, Zhiyong Fan, Hongkai Wu
A facile single-cell patterning (ScP) method was developed and integrated with time-of-flight secondary ion mass spectrometry (TOF-SIMS) for the study of drug-induced cellular phenotypic alterations. Micropatterned poly(dimethylsiloxane) (PDMS) stencil film and centrifugation-assisted cell trapping were combined for the preparation of on-surface single-cell microarrays, which exhibited both high site occupancy (>90%) and single-cell resolution (>97%). TOF-SIMS is a surface-sensitive mass spectrometry and is increasingly utilized in biological studies...
December 20, 2016: Analytical Chemistry
Sabine Holzer, Stefan Krivec, Sven Kayser, Julia Zakel, Herbert Hutter
A sputter beam, consisting of large O2 clusters, was used to record depth profiles of alkali metal ions (Me(+)) within thin SiO2 layers. The O2 gas cluster ion beam (O2-GCIB) exhibits an erosion rate comparable to the frequently used O2(+) projectiles. However, because of its high sputter yield the necessary beam current is considerably lower (factor 50), resulting in a decreased amount of excess charges at the SiO2 surface. Hence, a reduced electric field is obtained within the remaining dielectric layer. This drastically mitigates the Me(+) migration artifact, commonly observed in depth profiles of various dielectric materials, if analyzed by time-of-flight secondary ion mass spectrometry (ToF-SIMS) in dual beam mode...
February 9, 2017: Analytical Chemistry
Donya Farhanian, Gregory De Crescenzo, Jason R Tavares
Syngas is the product of gasification processes and is used for the production of petrochemicals. Little attention has been paid to its use in the production of oligomeric thin films under ambient conditions. Herein, the nature of the photoinitiated chemical vapor deposition of films made from syngas using high-wavelength ultraviolet light is discussed, including an exploration of the oligomeric films' structure, synthesis mechanism, and growth kinetics. Specifically, X-ray photoelectron spectroscopy and time-of-flight secondary ion mass spectrometry analyses provide insight into the chemical structure, illustrating the effect of photogenerated radicals in the formation of aliphatic, anhydride, and cyclic structures...
February 17, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
H Zhang, D Chiappe, J Meersschaut, T Conard, A Franquet, T Nuytten, M Mannarino, I Radu, W Vandervorst, A Delabie
Two-dimensional (2D) semiconducting transition metal dichalcogenides (TMDs) are of great interest for applications in nano-electronic devices. Their incorporation requires the deposition of nm-thin and continuous high-k dielectric layers on the 2D TMDs. Atomic layer deposition (ALD) of high-k dielectric layers is well established on Si surfaces: the importance of a high nucleation density for rapid layer closure is well known and the nucleation mechanisms have been thoroughly investigated. In contrast, the nucleation of ALD on 2D TMD surfaces is less well understood and a quantitative analysis of the deposition process is lacking...
February 7, 2017: Journal of Chemical Physics
Andreas K O Åslund, Einar Sulheim, Sofie Snipstad, Eva von Haartman, Habib Baghirov, Nichola Jayne Starr, Mia Kvåle Løvmo, Sylvie Lelu, David J Scurr, Catharina de Lange Davies, Ruth B Schmid, Ýrr A Mørch
Protein adsorption on nanoparticles (NPs) used in nanomedicine leads to opsonization and activation of the complement system in blood, which substantially reduces the blood circulation time of NPs. The most commonly used method to avoid protein adsorption, is to coat the NPs with polyethylene glycol, so called PEGylation. Although PEGylation is of utmost importance for designing the in vivo behavior of the NP, there is still a considerable lack of methods for characterization and fundamental understanding related to the PEGylation of NPs...
February 7, 2017: Molecular Pharmaceutics
Janneke Veerbeek, Liang Ye, Wouter Vijselaar, Tibor Kudernac, Wilfred G van der Wiel, Jurriaan Huskens
Controlling the doping concentration of silicon nanostructures is challenging. Here, we investigated three different monolayer doping techniques to obtain silicon nanowires with a high doping dose. These routes were based on conventional monolayer doping, starting from covalently bound dopant-containing molecules, or on monolayer contact doping, in which a source substrate coated with a monolayer of a carborane silane was the dopant source. As a third route, both techniques were combined to retain the benefits of conformal monolayer formation and the use of an external capping layer...
February 7, 2017: Nanoscale
Cuiwen He, Xuchen Hu, Rachel S Jung, Thomas A Weston, Norma P Sandoval, Peter Tontonoz, Matthew R Kilburn, Loren G Fong, Stephen G Young, Haibo Jiang
Cholesterol is a crucial lipid within the plasma membrane of mammalian cells. Recent biochemical studies showed that one pool of cholesterol in the plasma membrane is "accessible" to binding by a modified version of the cytolysin perfringolysin O (PFO*), whereas another pool is sequestered by sphingomyelin and cannot be bound by PFO* unless the sphingomyelin is destroyed with sphingomyelinase (SMase). Thus far, it has been unclear whether PFO* and related cholesterol-binding proteins bind uniformly to the plasma membrane or bind preferentially to specific domains or morphologic features on the plasma membrane...
February 6, 2017: Proceedings of the National Academy of Sciences of the United States of America
Mackenzie G Williams, Fei Gao, Ibtihel BenDhiab, Andrew Teplyakov
The covalent attachment of nonfunctionalized and carboxylic acid-functionalized carbon nanotubes to amine-terminated organic monolayers on gold and silicon surfaces is investigated. It is well established that the condensation reaction between a carboxylic acid and an amine is a viable method to anchor carbon nanotubes to solid substrates. The work presented here shows that the presence of the carboxylic group on the nanotube is not required for attachment to occur, as direct attachment via the substrate amine and the nanotube cage can take place...
February 7, 2017: Langmuir: the ACS Journal of Surfaces and Colloids
Satoshi Ninomiya, Kentaro Yoshimura, Lee Chuin Chen, Sen Takeda, Kenzo Hiraoka
Tissue samples from renal cell carcinoma patients were analyzed by electrospray droplet ion beam-induced secondary ion mass spectrometry (EDI/SIMS). Positively- and negatively-charged secondary ions were measured for the cancerous and noncancerous regions of the tissue samples. Although specific cancerous species could not be found in both the positive and negative secondary ion spectra, the spectra of the cancerous and noncancerous tissues presented different trends. For instance, in the m/z range of 500-800 of the positive secondary ion spectra for the cancerous tissues, the intensities for several m/z values were lower than those of the m/z+2 peaks (indicating one double bond loss for the species), whereas, for the noncancerous tissues, the inverse trend was obtained...
2017: Mass Spectrometry
Rohit Jaini, Peng Wang, Natalia Dudareva, Clint Chapple, John A Morgan
INTRODUCTION: The phenylpropanoid pathway is a source of a diverse group of compounds derived from phenylalanine, many of which are involved in lignin biosynthesis and serve as precursors for the production of valuable compounds, such as coumarins, flavonoids, and lignans. Consequently, recent efforts have been invested in mechanistically understanding monolignol biosynthesis, making the quantification of these metabolites vital. OBJECTIVE: To develop an improved and comprehensive analytical method for (i) extensively profiling, and (ii) accurately quantifiying intermediates of the monolignol biosynthetic network, using Arabidopsis thaliana as a model system...
February 1, 2017: Phytochemical Analysis: PCA
Dan Aoki, Ryutaro Asai, Rie Tomioka, Yasuyuki Matsushita, Hiroyuki Asakura, Masao Tabuchi, Kazuhiko Fukushima
To reveal the in planta behaviour of caesium (Cs), the stable isotope (133)Cs was administered into 3-year-old Cryptomeria japonica seedlings by the application of (133)CsCl aqueous solution to the bark surface. The administered (133)Cs was quantified by ICP-MS measurements, which showed transportation of (133)Cs in an ascending direction in the stem. Distribution of (133)Cs was visualized using freeze-fixed C. japonica woody stem samples and cryo-time-of-flight secondary ion mass spectrometry/scanning electron microscopy (cryo-TOF-SIMS/SEM) analysis...
January 27, 2017: Science of the Total Environment
Philipp Braeuninger-Weimer, Barry Brennan, Andrew J Pollard, Stephan Hofmann
The mechanism by which Cu catalyst pretreatments control graphene nucleation density in scalable chemical vapor deposition (CVD) is systematically explored. The intrinsic and extrinsic carbon contamination in the Cu foil is identified by time-of-flight secondary ion mass spectrometry as a major factor influencing graphene nucleation and growth. By selectively oxidizing the backside of the Cu foil prior to graphene growth, a drastic reduction of the graphene nucleation density by 6 orders of magnitude can be obtained...
December 27, 2016: Chemistry of Materials: a Publication of the American Chemical Society
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