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The profiling and identification of the metabolites of (+)‐catechin and study on their distribution in rats by HPLC‐DAD‐ESI‐IT‐TOF‐MS n technique
Published: Sep 16, 2013
Author(s): Jing Liang, Feng Xu, Ya‐Zhou Zhang, Xin‐Yu Zang, Dan Wang, Ming‐Ying Shang, Xuan Wang, De‐Hua Chui, Shao‐Qing Cai
Journal: Biomedical Chromatography
ABSTRACT (+)‐Catechin, a potential beneficial compound to human health, is widely distributed in plants and foods. A high‐performance liquid chromatography with diode array detector and combined with electrospray ionization ion trap time‐of‐flight multistage mass spectrometry method was applied to profile and identify the metabolites of (+)‐catechin in rats and to study the distribution of these metabolites in rat organs for the...
Read MoreSeparation of palonosetron stereoisomers by electrokinetic chromatography using sodium cholate as chiral selector: Comparison of separation modes and elucidation of migration orders
Published: Sep 16, 2013
Author(s): Shao‐Qiang Hu, Hong‐Bing Yang, Hai‐Jun Shi, Yong‐Hua Zhang, Zhuo Yang
Journal: ELECTROPHORESIS
Based on sodium cholate as chiral selector, four stereoisomers of palonosetron hydrochloride, i.e. PALO (3aS, 2S), PALO (3aR, 2R), PALO (3aS, 2R), and PALO (3aR, 2S), have been separated by five EKC modes, i.e. MEKC, solvent‐modified MEKC, cosurfactant‐modified MEKC, MEEKC, and MEEKC without cosurfactant. The performances of different modes were compared. The migration order and its change with experimental conditions were elucidated. In...
Read MoreGlass/ SU ‐8 microchip for electrokinetic applications
Published: Sep 16, 2013
Author(s): Renato Sousa Lima, Paulo Augusto Gomes Carneiro Leão, Alessandra Maffei Monteiro, Maria Helena Oliveira Piazzetta, Angelo Luiz Gobbi, Luiz Henrique Mazo, Emanuel Carrilho
Journal: ELECTROPHORESIS
In this communication, we describe the fabrication and electric characterization of a hybrid glass/SU‐8 microchannels for high‐performance electrokinetic applications. The bonding process employed SU‐8 film as intermediate layer with reduced baking times; all the procedure took less than 50 min (only about 10 min disregarding the cleaning and dehydration steps). Additionally, further steps to improve the adhesion of the substrate to the...
Read MoreFormation of the high pressure graphite and BC 8 phases in a cold compression experiment by Raman scattering
Published: Sep 14, 2013
Author(s): Shoko Odake, Pavel V. Zinin, Eric Hellebrand, Vitali Prakapenka, Yongsheng Liu, Shiming Hong, Katherine Burgess, Li‐Chung Ming
Journal: Journal of Raman Spectroscopy
We use Raman scattering to study phase transition in the graphitic g‐BC8 phase and graphite at high pressure up to 84 GPa. The E2g Raman active mode of graphite (G peak) can be detected up to 84 GPa. We demonstrate that there is (1) a phase transition in g‐BC8 and in graphite at 35 GPa and (2) that above 35 GPa, the g‐BC8 and graphite transform under high pressure to possibly fully sp3‐bonded, disordered hp‐BC8, and hp‐C phases. Below the phase transition, a polynomial fit...
Read MoreThe use of polyurethane as an elastomer in thermoplastic microfluidic devices and the study of its creep properties
Published: Sep 14, 2013
Author(s): Pan Gu, Toshikazu Nishida, Z. Hugh Fan
Journal: ELECTROPHORESIS
We report using polyurethane (PU) as an elastomer in microvalves integrated with thermoplastic microfluidic devices. Elastomer‐based microvalves have been used in a number of applications and the elastomer often used is PDMS. Although it is a convenient material for prototyping, PDMS has been recognized to possess shortcomings such as solvent incompatibility and unfavorable manufacturability. We investigated the use of PU as an elastomer...
Read MoreLiposomal nanotransporter for targeted binding based on nucleic acid anchor system
Published: Sep 14, 2013
Author(s): Lukas Nejdl, Miguel Angel Merlos Rodrigo, Jiri Kudr, Branislav Ruttkay‐Nedecky, Marie Konecna, Pavel Kopel, Ondrej Zitka, Jaromir Hubalek, Rene Kizek, Vojtech Adam
Journal: ELECTROPHORESIS
Microfluidic techniques have been developed intensively in recent years due to lower reagent consumption, faster analysis, and possibility of the integration of several analytical detectors into one chip. Electrochemical detectors are preferred in microfluidic systems, whereas liposomes can be used for amplification of the electrochemical signals. The aim of this study was to design a nanodevice for targeted anchoring of liposome as...
Read MoreRapid identification of human SNAP ‐25 transcript variants by a miniaturized capillary electrophoresis system
Published: Sep 14, 2013
Author(s): Nóra Németh, Márta Kerékgyártó, Mária Sasvári‐Székely, Zsolt Rónai, András Guttman
Journal: ELECTROPHORESIS
The 25 kDa synaptosomal‐associated protein (SNAP‐25) is a crucial component of the soluble N‐ethylmaleimide‐sensitive factor attachment protein receptor complex and plays an important role in neurotransmission in the central nervous system. SNAP‐25 has two different splice variants, SNAP‐25a and SNAP‐25b, differing in nine amino acids that results in a slight functional alteration of the generated soluble N‐ethylmaleimide‐sensitive factor attachment...
Read MoreUtilization of paramagnetic microparticles for automated isolation of free circulating mRNA as a new tool in prostate cancer diagnostics
Published: Sep 14, 2013
Author(s): Michaela Fojtu, Jaromir Gumulec, Jan Balvan, Martina Raudenska, Marketa Sztalmachova, Hana Polanska, Kristyna Smerkova, Vojtech Adam, Rene Kizek, Michal Masarik
Journal: ELECTROPHORESIS
Determination of serum mRNA gained a lot of attention in recent years, particularly from the perspective of disease markers. Streptavidin‐modified paramagnetic particles (SMPs) seem an interesting technique, mainly due to possible automated isolation and high efficiency. The aim of this study was to optimize serum isolation protocol to reduce the consumption of chemicals and sample volume. The following factors were optimized: amounts of...
Read MoreTilted hexagonal post arrays: DNA electrophoresis in anisotropic media
Published: Sep 14, 2013
Author(s): Zhen Chen, Kevin D. Dorfman
Journal: ELECTROPHORESIS
Using Brownian dynamics simulations, we show that DNA electrophoresis in a hexagonal array of micron‐sized posts changes qualitatively when the applied electric field vector is not coincident with the lattice vectors of the array. DNA electrophoresis in such “tilted” post arrays is superior to the standard “un‐tilted” approach; while the time required to achieve a resolution of unity in a tilted post array is similar to an un‐tilted array...
Read MoreMultidimensional separation of tryptic peptides from human serum proteins using reversed‐phase, strong cation exchange, weak anion exchange, and fused‐core fluorinated stationary phases
Published: Sep 13, 2013
Author(s): Alexander P. Boichenko, Natalia Govorukhina, Ate G. J. Zee, Rainer Bischoff
Journal: Journal of Separation Science
Proteome profiling of crude serum is a challenging task due to the wide dynamic range of protein concentrations and the presence of high‐abundance proteins, which cover >90% of the total protein mass in serum. Peptide fractionation on strong cation exchange, weak anion exchange in the electrostatic repulsion hydrophilic interaction chromatography (ERLIC) mode, RP C18 at pH 2.5 (low pH), fused‐core fluorinated at pH 2.5, and RP C18 at pH 9.7 (high...
Read MoreThe e‐tongue‐based classification and authentication of mineral water samples using cross‐correlation‐based PCA and Sammon's nonlinear mapping
Published: Sep 13, 2013
Author(s): Palash K. Kundu, Madhusree Kundu
Journal: Journal of Chemometrics
The present paper elaborates on the design of classifiers based on cross‐correlation‐based principal component analysis (PCA) and Sammon's nonlinear mapping (NLM) using current signals obtained from electronic tongue (e‐tongue) with commercial mineral water samples available in the Indian market. The pulse‐voltammetric method is used to capture the electroanalytical/electrochemical characteristics of the sampled mineral waters by...
Read MoreA perspective on the growth of chemometrics in Iran: a glance into activities between 2005 and 2012
Published: Sep 13, 2013
Author(s): Abdolhossein Naseri, Morteza Bahram
Journal: Journal of Chemometrics
Although the first publications in the field of chemometrics by Iranian researchers go back nearly 23 years, Iran's chemometrics has experienced significant growth after the year 2000. More than 1500 papers have been published by Iranian chemometricians between 2005 and 2012 which is about seven times more than those published before 2005. The aim of this review is to present a perspective about Iran's chemometrics developments. The role...
Read MoreDistinguishing chemical and electromagnetic enhancement in surface‐enhanced Raman spectra: The case of para ‐nitrothiophenol
Published: Sep 12, 2013
Author(s): Martin Thomas, Stefan Mühlig, Tanja Deckert‐Gaudig, Carsten Rockstuhl, Volker Deckert, Philipp Marquetand
Journal: Journal of Raman Spectroscopy
Surface‐enhanced Raman spectra are simulated using a combined classical electrodynamics/real‐time time‐dependent density functional theory approach and compared to experiments. Emphasis is put on discerning between chemical and electromagnetic enhancement. Therefore, three different calculation scenarios are investigated using para‐nitrothiophenol as a test molecule. In the first one, corresponding to electromagnetic enhancement, we simulate the...
Read MorePerspectives in process analysis
Published: Sep 11, 2013
Author(s): Rudolf W. Kessler
Journal: Journal of Chemometrics
Process analysis is a transdisciplinary technology. Process chemists, process engineers, chemometricians, and many other technologists must work together and put more emphasis on the essentials of science of each discipline. This perspective analyzes potential strategies for intelligent production in the future. It emphasizes the need for a holistic approach where multimodality will be a bedrock supporting the production of smart...
Read MoreApplication of orthogonal space regression to calibration transfer without standards
Published: Sep 11, 2013
Author(s): Zhaozhou Lin, Bing Xu, Yang Li, Xinyuan Shi, Yanjiang Qiao
Journal: Journal of Chemometrics
To transfer a calibration model in cases where the standardization samples are rare or unstable, a method based on orthogonal space regression (OSR) is proposed. It uses virtual standardization spectra to account for response changes between instruments or batches. A comparative study of the proposed OSR, piecewise direct standardization, finite impulse response, orthogonal signal correction, and model updating (MU) was conducted on both...
Read MoreSimultaneous determination of aurantio‐obtusin, chrysoobtusin, obtusin and 1‐desmethylobtusin in rat plasma by UHPLC‐MS/MS
Published: Sep 11, 2013
Author(s): Wei‐dong Zhang, Peng‐yuan Wang, Ying Wang, Qing Wang, Yi Gu, Jun Cao, Shao‐qing Wang, Xiao‐juan Wang
Journal: Biomedical Chromatography
ABSTRACT A sensitive and reliable ultra‐high‐performance liquid chromatography–electrospray ionization–tandem mass spectrometry (UHPLC‐MS/MS) method was developed and validated for the simultaneous determination of four active components of Semen Cassiae extract (aurantio‐obtusin, chrysoobtusin, obtusin and 1‐desmethylobtusin) in rat plasma after oral administration. Chromatographic separation was achieved on an Agilent Poroshell...
Read MoreRaman study of cation effect on sulfate vibration modes in solid state and in aqueous solutions
Published: Sep 11, 2013
Author(s): Kawther Ben Mabrouk, Thomas H. Kauffmann, Hassen Aroui, Marc D. Fontana
Journal: Journal of Raman Spectroscopy
Raman spectra of potassium, sodium, and ammonium sulfates (K2SO4, Na2SO4, and (NH4)2SO4) are reported and analyzed. These sulfates have been investigated under two states: solid (anhydrous and hydrated) salts and aqueous solutions. The effects of monovalent ions (K+, Na+, and NH4+) and hydration on the position of Raman lines assigned to internal vibrations of sulfate anion SO42− are discussed. In solid salts, the line position of each Raman peak is shown to...
Read MorePolarization‐resolved high‐resolution Raman spectroscopy with a light‐emitting diode
Published: Sep 11, 2013
Author(s): Miriam A. Schmidt, Johannes Kiefer
Journal: Journal of Raman Spectroscopy
We demonstrate the use of a light‐emitting diode (LED) based experimental setup for collecting polarization‐resolved Raman spectra with good spectral resolution. The combination of a commercial red LED (630 nm), a 1‐nm bandwidth laser‐line filter, and a polarizing prism is used as a light source. Polarization‐resolved spectra in dimethyl sulfoxide are recorded and compared with the corresponding laser‐Raman spectra. The LED‐excited...
Read MoreMetal–organic frameworks: a novel SERS substrate
Published: Sep 11, 2013
Author(s): Tsung‐Han Yu, Chin‐Hsian Ho, Cheng‐You Wu, Ching‐Hsuan Chien, Chia‐Her Lin, Szetsen Lee
Journal: Journal of Raman Spectroscopy
We report the direct observation of surface‐enhanced Raman scattering (SERS) effect using metal–organic frameworks (MOFs) as substrates. Without the aid of any metal colloids or enhancing agents, the SERS signals of methyl orange (MO) adsorbed in MOFs were observed and even remained active if the organic linkers in MOFs were completely removed by high temperature and O2 plasma treatments. It implies that the SERS active site is at the...
Read MoreA high‐resolution X‐ray fluorescence spectrometer and its application at SSRF
Published: Sep 10, 2013
Author(s): Xing Gao, Songqi Gu, Qian Gao, Yang Zou, Zheng Jiang, Shuo Zhang, Xiangjun Wei, Haisheng Yu, Guodong Sheng, Peiquan Duan, Yuying Huang
Journal: X-Ray Spectrometry
A high‐resolution X‐ray fluorescence spectrometer based on Rowland circle geometry was developed and installed at BL14W1 XAFS beamline of Shanghai Synchrotron Radiation Facility. The spectrometer mainly consists of three parts: a sample holder, a spherically curved Si crystal, and an avalanche photodiode detector. The simplicity of the spectrometer makes it easily assembled on the general purpose X‐ray absorption beamline. X‐ray emission...
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