EarlyView Articles

Determination of 10‐chloromethyl‐11‐demethyl‐12‐oxo‐calanolide A in rat plasma using liquid chromatography–tandem mass spectrometry and its application to pharmacokinetics

Published: Apr 24, 2014

Author(s): Li Sheng, Qinghao Zhang, Zhihao Liu, Xin Liu, Baolian Wang, Hui Chen, Yan Li

Journal: Biomedical Chromatography

ABSTRACT A rapid and specific liquid chromatography–tandem mass spectrometry for the quantitation of 10‐chloromethyl‐11‐demethyl‐12‐oxo‐calanolide A (F18), a small‐molecule nonnucleoside reverse transcriptase inhibitor, was developed and validated in rat plasma. F18 was monitored by positive electrospray ionization in the selected reaction monitoring mode. The standard curve was linear over the range of 2–1000 ng/mL. The method was...

An HPLC method for the quantitation of 3‐pentylbenzo[c]thiophen‐1(3H)‐one in dog plasma and its application to a pharmacokinetic study

Published: Apr 24, 2014

Author(s): Ting‐Ting Li, Kai Hua, Xiao Sheng, Ling Liu, Jia‐Ni Tan, Lin‐Na Wang, Bo Wei, Hui Ji, Yi‐Hua Zhang

Journal: Biomedical Chromatography

ABSTRACT A simple, sensitive and reproducible high‐performance liquid chromatography (HPLC) assay method was developed for the estimation of 3‐pentylbenzo[c]thiophen‐1(3H)‐one (S5), a potential anti‐ischemic stroke agent, in dog plasma. The analytical procedure involves protein precipitation of S5 and nobiletin (internal standard) from dog plasma with acetonitrile. Chromatographic separation was achieved on Sapphire C18 analytical column with...

Validation of a sensitive LC/MS/MS method for the determination of telaprevir and its R ‐isomer in human plasma

Published: Apr 24, 2014

Author(s): Xinhui Chen, Lane R. Bushman, Kevin J. McAllister, Peter L. Anderson, Jennifer J. Kiser

Journal: Biomedical Chromatography

ABSTRACT The purpose of this study was to validate a reversed‐phase high‐performance liquid chromatographic (HPLC), tandem mass spectrometry (MS/MS) assay for the determination of telaprevir and its R‐diastereomer (VRT‐127394) in acidified and nonacidified human plasma. The chromatographic baseline separation of telaprevir and telaprevir‐R was performed on a Waters XBridgeTM BEH Shield C18, 2.1 × 75 mm column with a 2.5 µm particle size, under...

Sputter depth profiling: past, present, and future

Published: Apr 24, 2014

Author(s): S. Hofmann

Journal: Surface and Interface Analysis

Sputter depth profiling is a direct method to obtain the in‐depth distribution of composition in thin films, at surfaces and at interfaces. It was developed in conjunction with the main methods of surface and interface analysis (AES, XPS, and SIMS). During the past decades, progress in depth profiling is characterized by the aim to obtain optimally resolved depth profiles. This is mainly achieved by experimentally identifying the decisive...

Comparison of nanostructured blend homopolymers and diblock copolymers by AFM and TOF‐SIMS

Published: Apr 24, 2014

Author(s): Minhwa Kang, Jihye Lee, Yeonhee Lee

Journal: Surface and Interface Analysis

Poly(styrene‐b‐methyl methacrylate) (PS‐b‐PMMA) and poly(styrene‐b‐ethyl hexylacrylate) (PS‐b‐PEHA) were used to investigate microphase separation in block copolymer films. Blend homopolymers were also used to compare their nanostructures on the surface with those of diblock copolymers. Atomic force microscopy (AFM) and time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) were used to obtain the nanostructural information of the diblock...

Characterization and sequence determination of pen inks, red sealing inks, and laser toners by TOF‐SIMS and ATR FTIR

Published: Apr 24, 2014

Author(s): Jihye Lee, Seon Hee Kim, Youn‐Jeong Cho, Yun Sik Nam, Kang‐Bong Lee, Yeonhee Lee

Journal: Surface and Interface Analysis

Document authentication is one of the most important fields in forensic science and includes analysis of handwriting, seal imprint, and printed materials. In this study, we investigated intersection lines by pen inks, red stamping ink, and laser toner using time‐of‐flight secondary ion mass spectrometry (TOF‐SIMS) and attenuated total reflectance Fourier transform infrared spectroscopy (ATR FTIR). TOF‐SIMS is very useful when the quantity...

A surface analytical investigation of cerium‐based conversion coatings deposited onto an AA2024‐T3 aluminium alloy cladding layer

Published: Apr 24, 2014

Author(s): S. J. Hinder, R. Grilli, M. Rustame, W. I. A. Santos, M. A. Baker, I. Costa

Journal: Surface and Interface Analysis

Cerium‐based conversion coatings are being investigated as alternatives to chromating treatments for the corrosion protection of aluminium and its alloys because of the environmentally unfriendly nature of the chromating process. This study investigates the surface film composition, structure and corrosion performance following a two‐step surface treatment for an AA2024‐T3 clad aluminium alloy. The two‐step treatment comprised of an...

Top‐down tandem mass spectrometry on RN ase A and B using a Q h/ FT ‐ ICR hybrid mass spectrometer

Published: Apr 24, 2014

Author(s): Sandrine Bourgoin‐Voillard, Nancy Leymarie, Catherine E. Costello

Journal: PROTEOMICS

Protein characterization using top‐down approaches emerged with advances in high‐resolution mass spectrometers and increased diversity of available activation modes: collision‐induced dissociation (CID), infrared multiphoton dissociation (IRMPD) electron capture dissociation (ECD), and electron transfer dissociation (ETD). Nevertheless, top‐down approaches are still rarely used for glycoproteins. Hence, this work summarized the capacity...

Investigating macromolecular complexes using top‐down mass spectrometry

Published: Apr 24, 2014

Author(s): Elisabetta Boeri Erba

Journal: PROTEOMICS

MS has emerged as an important tool to investigate noncovalent interactions between proteins and various ligands (e.g. other proteins, small molecules, or drugs). In particular, ESI under so‐called “native conditions” (a.k.a. “native MS”) has considerably expanded the scope of such investigations. For instance, ESI quadrupole time of flight (Q‐TOF) instruments have been used to probe the precise stoichiometry of protein assemblies, the...

MBD5 and MBD6 interact with the human PR‐DUB complex through their methyl‐CpG‐binding domain

Published: Apr 24, 2014

Author(s): H. Irem Baymaz, Alexandra Fournier, Sophie Laget, Zongling Ji, Pascal W.T.C. Jansen, Arne H. Smits, Laure Ferry, Anneloes Mensinga, Ina Poser, Andrew Sharrocks, Pierre‐Antoine Defossez, Michiel Vermeulen

Journal: PROTEOMICS

MBD5 and MBD6 are two members of the methyl‐CpG‐binding domain (MBD) family of proteins that are poorly characterized. Studies performed thus far have failed to show binding of the MBD5 and MBD6 MBD to methylated DNA. Here, we show that both MBD5 and MBD6 interact with the mammalian PR‐DUB Polycomb protein complex in a mutually exclusive manner. Strikingly, the MBD of MBD5 and MBD6 is both necessary and sufficient to mediate this...

Ultraviolet photodissociation enhances top‐down mass spectrometry as demonstrated on green fluorescent protein variants

Published: Apr 24, 2014

Author(s): Xibei Dang, Nicolas L. Young

Journal: PROTEOMICS

Ultraviolet photodissociation (UVPD) is a compelling fragmentation technique with great potential to enhance proteomics generally and top‐down MS specifically. In this issue, Cannon et al. (Proteomics 2014, 14, XXXX–XXXX) use UVPD to perform top‐down MS on several sequence variants of green fluorescent protein and compare the results to CID, higher energy collision induced dissociation, and electron transfer dissociation. As compared to the other...

Core level studies of calcite and dolomite

Published: Apr 22, 2014

Author(s): Lauri Järvinen, Jarkko Leiro, Markku Heinonen

Journal: Surface and Interface Analysis

Conventional X‐ray photoelectron spectroscopy (XPS) and synchrotron‐based X‐ray photoelectron spectroscopy (HRXPS) have been used to study Iceland spar calcite (CaCO3) and dolomite (CaMg(CO3)2). The obtained full widths at half maximum (FWHMs) are mostly narrower than in the previous results, which together with the symmetry of the fitted peaks indicate effective neutralisation of surface charging. Some previously unidentified features ...

MRI assessment of cerebral oxygen metabolism in cocaine‐addicted individuals: hypoactivity and dose dependence

Published: Apr 22, 2014

Author(s): Peiying Liu, Hanzhang Lu, Francesca M. Filbey, Carol A. Tamminga, Yan Cao, Bryon Adinoff

Journal: NMR in Biomedicine

Long‐term cocaine use is known to negatively impact neural and cerebrovascular systems. However, the use of imaging markers to separately assess these parameters remains challenging. The primary reason is that most functional imaging markers, such as cerebral blood flow, functional connectivity, and task‐evoked functional MRI, are known to reflect a complex interplay between neural and vascular components, thus the interpretation of the...

Application of a new fiber coating based on electrochemically reduced graphene oxide for the cold‐fiber headspace solid‐phase microextraction of tricyclic antidepressants

Published: Apr 22, 2014

Author(s): Mohammad Hossein Banitaba, Saied Saeed Hosseiny Davarani, Hamid Ahmar, Siyavash Kazemi Movahed

Journal: Journal of Separation Science

A new fiber based on the electrochemical reduction of graphene oxide was prepared on a copper wire for solid‐phase microextraction (SPME) applications. The prepared fiber was used for the SPME and gas chromatographic analysis of tricyclic antidepressants (TCADs), including amitriptyline, trimipramine, and clomipramine. The feasibility of direct‐immersion and headspace modes of SPME for the determination of TCADs was studied. The effects...

An improved LC‐MS/MS method for quantitation of indapamide in whole blood: application for a bioequivalence study

Published: Apr 22, 2014

Author(s): Guilherme Araújo Pinto, Kátia Isabel Fercondini Pastre, Karini Bruno Bellorio, Leonardo Souza Teixeira, Weidson Carlo Souza, Fernanda Crunivel Abreu, Fabiana Fernandes Santana e Silva Cardoso, Gerson Antônio Pianetti, Isabela Costa César

Journal: Biomedical Chromatography

ABSTRACT An improved LC‐MS/MS method for the quantitation of indapamide in human whole blood was developed and validated. Indapamide‐d3 was used as internal standard (IS) and liquid–liquid extraction was employed for sample preparation. LC separation was performed on Synergi Polar RP‐column (50 × 4.6 mm i.d.; 4 µm) and mobile phase composed of methanol and 5 mm aqueous ammonium acetate containing 1 mm formic acid (60:40), at flow rate of...

5,10‐Methylene‐tetrahydrofolate dissociates into tetrahydrofolate and formaldehyde at physiological pH and acidic pH, typical conditions used during sample extraction and LC‐MS/MS analysis of biological samples

Published: Apr 22, 2014

Author(s): Margaretha Jägerstad, Jelena Jastrebova

Journal: Biomedical Chromatography

Molecularly imprinted polymeric sensings layers grafted from aryl diazonium‐modified surfaces for electroanalytical applications. A mini review

Published: Apr 22, 2014

Author(s): Idriss Bakas, Zakaria Salmi, Sarra Gam‐Derouich, Mohamed Jouini, Sandrine Lépinay, Benjamin Carbonnier, Akila Khlifi, Rafik Kalfat, Florence Geneste, Yusuf Yagci, Mohamed M. Chehimi

Journal: Surface and Interface Analysis

We review our strategy to attach polymerization initiators to electrode surfaces by electroreduction of aryl diazonium salts. The ~5 nm‐thick aryl layers efficiently initiate the growth of crosslinked polymer grafts prepared in the presence of template molecules. We address the important parameters in obtaining highly sensitive molecularly imprinted vinylic polymer layers grafted on working electrodes such as glassy carbon, gold and...

Nondestructive compositional depth profiling using variable‐kinetic energy hard X‐ray photoelectron spectroscopy and maximum entropy regularization

Published: Apr 22, 2014

Author(s): C. Weiland, J. Krajewski, R. Opila, V. Pallem, C. Dussarrat, J. C. Woicik

Journal: Surface and Interface Analysis

We discuss the calculation of nondestructive compositional depth profiles from regularization of variable kinetic energy hard X‐ray photoelectron spectroscopy (VKE‐XPS) data, adapting techniques developed for angle‐resolved XPS. Simulated TiO2/Si film structures are analyzed to demonstrate the applicability of regularization techniques to the VKE‐XPS data and to determine the optimum choice of regularization function and the number of data points. We...

Electrospray droplet impact/secondary ion mass spectrometry (EDI/SIMS) using mixed solvents of water/methanol and water/2‐propanol as projectile droplets

Published: Apr 22, 2014

Author(s): Rio Takaishi, Kenzo Hiraoka

Journal: Surface and Interface Analysis

The electrospray droplet impact/secondary ion mass spectrometry (EDI/SIMS) using charged electrospray water droplets realized the atomic and molecular level etching with leaving little damage on the surface. In this work, the binary mixtures of water and alcohols (methanol and 2‐propanol) were examined as the charged electrospray droplets. The increase of desorption efficiency and softer ionization are observed for rhodamine B and...

Developing New Methods to Answer Old and New Questions in Neurodegenerative Diseases

Published: Apr 22, 2014

Author(s): Fouzi El Magraoui, Martin Eisenacher, Andreas Schrötter, Katja Kuhlmann, Helmut Heinsen, Per Andrén, Peter Nilsson, Anna Häggmark, Gerd Schmitz, Peter Verhaert, Christoph Borchers, Jong‐Shin Yoo, Bong‐Hee Lee, Helmut E. Meyer, Lea T. Grinberg

Journal: PROTEOMICS

The HUPO Brain Proteome Project (HUPO BPP) held its 21st workshop in Honolulu, Hawaii. During the 23–24 January 2014 the island became the center of the open workshop of the scientific community.