EarlyView Articles

Study on growth rate of TiO ₂ nanostructured thin films: simulation by molecular dynamics approach and modeling by artificial neural network

Published: Aug 12, 2013

Author(s): Alireza Bahramian

Journal: Surface and Interface Analysis

ABSTRACT Effects of the deposition process parameters on the thickness of TiO2 nanostructured film were simulated using the molecular dynamics (MD) approach and modeled by the artificial neural network (ANN) and regression method. Accordingly, TiO2 nanostructured film was prepared experimentally with the sol–gel dip‐coating method. Structural instabilities can be expected, due to short‐ and/or long‐range intermolecular forces, leading to the...

Determination of acidity constants and ionic mobilities of polyprotic peptide hormones by CZE

Published: Aug 12, 2013

Author(s): Veronika Šolínová, Václav Kašička

Journal: ELECTROPHORESIS

CZE has been applied to determination of thermodynamic acidity constants (pKa) of ionogenic groups and actual ionic mobilities of polyprotic peptides–synthetic human and salmon gonadotropin‐releasing hormones and their derivatives and fragments. First, the mixed acidity constants, , of ionogenic groups, and actual ionic mobilities, mi, of gonadotropin‐releasing hormone peptides were determined by nonlinear regression analysis of pH dependence of...

Liquid chromatography of synthetic polymers under critical conditions of enthalpic interactions 4: Sample recovery

Published: Aug 12, 2013

Author(s): Alena Šišková, Eva Macová, Danilo Corradini, Dušan Berek

Journal: Journal of Separation Science

Reduced sample recovery is a frequent feature of LC of macromolecules under critical conditions of enthalpic interactions (LC CC). Several methods of assessment of LC CC sample recovery are compared. A novel approach is based on an online combination of the. The LC CC column with a noninteractive SEC column. It provides not only the amount but also the molar mass of the eluted/withheld polymer. The procedure was tested with poly(methyl...

Green methodology based on dispersive liquid–liquid microextraction and micellar electrokinetic chromatography for 5‐nitroimidazole analysis in water samples

Published: Aug 12, 2013

Author(s): Maykel Hernández‐Mesa, Carmen Cruces‐Blanco, Ana M. García‐Campaña

Journal: Journal of Separation Science

Dispersive liquid–liquid microextraction has been proposed as an extraction technique combined with micellar electrokinetic chromatography (MEKC) for the analysis of eight 5‐nitroimidazole compounds, including some metabolites, in water samples. Determination has been carried out using a diode array detector, employing 20 mM sodium phosphate and 150 mM SDS as separation buffer. Separation has taken place under a voltage of 25 kV and a...

Development and optimization of the determination of pharmaceuticals in water samples by SPE and HPLC with diode‐array detection

Published: Aug 12, 2013

Author(s): Dragana Mutavdžić Pavlović, Danijela Ašperger, Dijana Tolić, Sandra Babić

Journal: Journal of Separation Science

This paper describes the development, optimization, and validation of a method for the determination of five pharmaceuticals from different therapeutic classes (antibiotics, anthelmintics, glucocorticoides) in water samples. Water samples were prepared using SPE and extracts were analyzed by HPLC with diode‐array detection. The efficiency of 11 different SPE cartridges to extract the investigated compounds from water was tested in...

Serial coupling of RP and zwitterionic hydrophilic interaction LC – MS : S uspects screening of diclofenac transformation products by oxidation with a boron‐doped diamond electrode

Published: Aug 12, 2013

Author(s): Mohamad Rajab, Giorgia Greco, Carolin Heim, Brigitte Helmreich, Thomas Letzel

Journal: Journal of Separation Science

The presence of pollutants and their transformation products (TPs) in the water system is a big concern because of possible adverse effects on the aquatic environment. Their identification is still a challenge that requires the combination of different chromatographic techniques. In the current research, serial coupling of RPLC and zwitterionic hydrophilic interaction LC with TOF‐MS was investigated as a single separation technique for...

Dependence of the distribution constant in liquid–liquid partition equilibria on the van der W aals molecular surface area

Published: Aug 12, 2013

Author(s): Serban C. Moldoveanu, Victor David

Journal: Journal of Separation Science

The direct calculation of free energy of interactions between a solute j and two immiscible liquids shows a linear dependence between the (logarithm of) the distribution constant in liquid–liquid partition equilibrium log Kj and the van der Waals surface area of the solute. The study provides a thermodynamic proof for the formula log KBA,j = c1 log KBC,j + c2 that describes the linear dependence between (the logarithm of) the distribution constant for...

Comparison of different extraction methods for the determination of α‐ and β‐thujone in sage ( Salvia officinalis L.) herbal tea

Published: Aug 12, 2013

Author(s): Agnieszka Arceusz, Andrea Occhipinti, Andrea Capuzzo, Massimo E. Maffei

Journal: Journal of Separation Science

Salvia officinalis L. (sage) is an important industrial plant used both for food and pharmaceutical purposes. The terpene fraction of this plant is responsible for many of its therapeutic and culinary properties. We used different extraction methods Tenax TA® purge and trap, headspace (HS) solid‐phase microextraction, HS sorptive extraction, and stir bar sorptive extraction to analyze the terpene fraction extracted from sage tea by GC–MS....

Effect of electric field on the partitioning behavior of solutes in entropic interaction chromatography

Published: Aug 12, 2013

Author(s): Qing‐Hong Shi, Guo‐Dong Jia, Liang Xu, Yan Sun

Journal: Journal of Separation Science

In this study, a novel column design with a round cross‐section was proposed to be suitable for a transverse electric field (EF). Additionally, two beads for entropic interaction chromatography (EIC) were prepared by grafting glycidyl methacrylate onto Toyopearl HW‐65F (T65F) beads. Solute partitioning was then investigated to elucidate the role of graft polymerization with and without an EF. In a T65F column, solute partitioning was...

Enantiomeric separation of citalopram base by supercritical fluid chromatography

Published: Aug 12, 2013

Author(s): Min Li, Zongbi Bao, Baogen Su, Huabin Xing, Yiwen Yang, Qilong Ren

Journal: Journal of Separation Science

The chiral separation of citalopram base by supercritical fluid chromatography on a semipreparative Chiralpak AD column was studied with the use of three alcohol‐type modifiers (methanol, ethanol, and 2‐propanol) with different volume percentages (5, 10, and 15%). The best separation was achieved when 10% 2‐propanol was used in the presence of 0.1% diethylamine as additive. Under these conditions, the resolution reached 2.15 and the...

Enantiomeric separation of proton pump inhibitors on new generation chiral columns using LC and supercritical fluid chromatography

Published: Aug 12, 2013

Author(s): Lakshmi Narayana Chennuru, Thirupathi Choppari, Subrahmanyam Duvvuri, Pramod Kumar Dubey

Journal: Journal of Separation Science

The enantioselectivity of proton pump inhibitors, namely, omeprazole, lansoprazole, rabeprazole, pantoprazole, tenatoprazole, and ilaprazole were studied using new generation chiral packing materials: CHIRALPAK IA, CHIRALPAK IB, and CHIRALPAK IC. Two versatile techniques, HPLC and supercritical fluid chromatography (SFC) were used in this study. CHIRALPAK IC has shown superior selectivity under both LC and SFC conditions, whereas...

Novel affinity purification of monomeric sarcosine oxidase expressed in Escherichia coli

Published: Aug 12, 2013

Author(s): Yanjun Tong, Yu Xin, Hailin Yang, Ling Zhang, Xiumei Tao, Hui Xu, Wu Wang

Journal: Journal of Separation Science

An efficient affinity‐purification protocol for Bacillus monomeric sarcosine oxidase (SOX) expressed in Escherichia coli BL21 (DE3) was developed. 4‐Aminopyrrole‐2‐carboxylic acid was chosen as the affinity ligand, which was coupled with Sepharose CL 4B via spacers composed of epichlorohydrin and ethylenediamine. With the affinity medium, the purification process consisted of only one affinity chromatography step to capture monomeric SOX. The...

Determination of newly synthesized lipoic acid–niacin dimer in rat plasma by UPLC/electrospray ionization tandem mass spectrometry: assay development, validation and application to a pharmacokinetic study

Published: Aug 12, 2013

Author(s): Xiao Chen, Jingwen Gao, Yiming Jiang, Ping Huang, Yuhui Xie, Rongbiao Pi, Shuzhen Zhu, Meicun Yao

Journal: Biomedical Chromatography

ABSTRACT A simple, sensitive and specific ultra‐performance liquid chromatography/tandem mass spectrometry (UPLC‐MS/MS) method was developed to determine the newly synthesized compound lipoic acid–niacin dimer (N2L) in plasma. Plasma samples were precipitated by methanol using tetrahydropalmatine as internal standard. Chromatographic separation was achieved on an Acquity BEH C18 (2.1 × 50 mm i.d., 1.7 µm) column; the mobile phase contains...

The impact of blood on liver metabolite profiling – a combined metabolomic and proteomic approach

Published: Aug 12, 2013

Author(s): Saray Ly‐Verdú, Alexander Schaefer, Melanie Kahle, Thomas Groeger, Susanne Neschen, Jose M. Arteaga‐Salas, Marius Ueffing, Martin Hrabe Angelis, Ralf Zimmermann

Journal: Biomedical Chromatography

ABSTRACT Metabolomics has entered the well‐established omic sciences as it is an indispensable information resource to achieve a global picture of biological systems. The aim of the present study was to estimate the influence of blood removal from mice liver as part of sample preparation for metabolomic and proteomic studies. For this purpose, perfused mice liver tissue (i.e. with blood removed) and unperfused mice liver tissue ...

The role of metabolic imaging in radiation therapy of prostate cancer

Published: Aug 12, 2013

Author(s): V. Y. Zhang, A. Westphalen, L. Delos Santos, Z. L. Tabatabai, K. Shinohara, D. B. Vigneron, J. Kurhanewicz

Journal: NMR in Biomedicine

The goal of this study was to correlate prostatic metabolite concentrations from snap‐frozen patient biopsies of recurrent cancer after failed radiation therapy with histopathological findings, including Ki‐67 immunohistochemistry and pathologic grade, in order to identify quantitative metabolic biomarkers that predict for residual aggressive versus indolent cancer. A total of 124 snap‐frozen transrectal ultrasound (TRUS)‐guided biopsies...

Diffusion tensor imaging detects treatment effects of FTY720 in experimental autoimmune encephalomyelitis mice

Published: Aug 12, 2013

Author(s): Xiaojie Wang, Joan K. Brieland, Joong H. Kim, Ying‐Jr Chen, Janet O'Neal, Shawn R. O'Neil, Tsang‐Wei Tu, Kathryn Trinkaus, Sheng‐Kwei Song

Journal: NMR in Biomedicine

Fingolimod (FTY720) is an orally available sphingosine‐1‐phosphate (S1P) receptor modulator reducing relapse frequency in patients with relapsing–remitting multiple sclerosis (RRMS). In addition to immunosuppression, neuronal protection by FTY720 has also been suggested, but remains controversial. Axial and radial diffusivities derived from in vivo diffusion tensor imaging (DTI) were employed as noninvasive biomarkers of axonal injury and...

Quantitative magnetization transfer MRI of desmoplasia in pancreatic ductal adenocarcinoma xenografts

Published: Aug 12, 2013

Author(s): Weiguo Li, Zhuoli Zhang, Jodi Nicolai, Guang‐Yu Yang, Reed A. Omary, Andrew C. Larson

Journal: NMR in Biomedicine

Quantitative assessment of desmoplasia in pancreatic ductal adenocarcinoma (PDAC) may be critical for staging or prediction of response to therapy. We performed quantitative magnetization transfer (qMT) MRI measurements in 18 mouse xenograft tumors generated from three PDAC cell lines. The qMT parameter bound proton fraction (BPF) was found to be significantly higher in tumors grown using the BxPC‐3 cell line (5.31 ± 0.87, mean ± standard...

Effect of taxane‐based neoadjuvant chemotherapy on fibroglandular tissue volume and percent breast density in the contralateral normal breast evaluated by 3T MR

Published: Aug 12, 2013

Author(s): Jeon‐Hor Chen, Wei‐Fan Pan, Julian Kao, Jocelyn Lu, Li‐Kuang Chen, Chih‐Chen Kuo, Chih‐Kai Chang, Wen‐Pin Chen, Christine E. McLaren, Shadfar Bahri, Rita S. Mehta, Min‐Ying Su

Journal: NMR in Biomedicine

The aim of this study was to evaluate the change of breast density in the normal breast of patients receiving neoadjuvant chemotherapy (NAC). Forty‐four breast cancer patients were studied. MRI acquisition was performed before treatment (baseline), and 4 and 12 weeks after treatment. A computer‐algorithm‐based program was used to segment breast tissue and calculate breast volume (BV), fibroglandular tissue volume (FV), and percent density...

Near‐infrared spectroscopy and partial least squares‐class modeling (PLS‐CM) for metabolomics fingerprinting discrimination of intervention breakfasts ingested by obese individuals

Published: Aug 11, 2013

Author(s): Beatriz Álvarez‐Sánchez, Feliciano Priego‐Capote, Juan García‐Olmo, María C. Ortiz‐Fernández, Luis A. Sarabia‐Peinador, María D. Luque de Castro

Journal: Journal of Chemometrics

Near‐infrared spectroscopy has been used in nutritional metabolomics fingerprinting for the assessment of the intake of intervention breakfasts prepared with four different vegetable oils that were previously subjected to a deep frying process of 20 cycles for 5 min at 180°C. The target oils were an extra virgin olive oil and three varieties of refined sunflower oil. Of the three latter, one of them was used as such, other was spiked with...

Report on the Third International Conference on X‐ray analysis, 20–24 August 2012, Ulaanbaatar, Mongolia

Published: Aug 10, 2013

Author(s): A. Revenko, P. Zuzaan, S. Davaa

Journal: X-Ray Spectrometry