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Mobile phase additive

Norbert Rácz, Imre Molnár, Arnold Zöldhegyi, Hans-Jürgen Rieger, Róbert Kormány
Chromatographic methods are progressing continuously. Increasing sample complexity and safety expectations lead to higher regulatory demands, hence challenges in liquid chromatography analysis are rising, even today, when faster and faster chromatographic systems are extensively employed and become widely accessible for successful method development. The goal of this study was to investigate the impact of mobile phase influences as important factors of selectivity tuning in method development. This would mitigate mobile phase-related robustness issues throughout the method's lifecycle...
August 2, 2018: Journal of Pharmaceutical and Biomedical Analysis
Mohamed Morsy-Osman, Francesco Fresi, Enrico Forestieri, Marco Secondini, Luca Potì, Fabio Cavaliere, Stephane Lessard, David V Plant
We experimentally demonstrate 50 Gb/s transmission below an uncorrected bit error rate (BER) of 10-3 in the C band over a transmission reach that extends from 0 to 20 km using combined amplitude and phase shift (CAPS) codes. The CAPS signal, which is not required to be specifically dispersion compensated for each reach within the 20 km operating range, is amenable for simple direct detection using a single photodetector without any subsequent digital signal processing (DSP). Hence, the presented solution constitutes a potentially attractive low cost solution for mobile Xhaul applications employing single mode fiber interconnects with reaches extending to 20 km...
July 9, 2018: Optics Express
Noha M Hosny, Noha N Atia, Samia M El-Gizawy, Dalia M Badary, Mohammad S Hareedy
The present study was designed to evaluate the potential protective effects of the cysteinyl leukotriene receptor blocker montelukast (MNK) and the xanthine oxidase inhibitor febuxostat (FBX) and their combination on a model of acute gouty arthritis induced by intraarticular injection of monourate sodium crystal (MUC) injection in rats. Additionally, we established an HPTLC method for the quantitative determination of both drugs simultaneously and applied this method to detect this combination in rat plasma...
August 16, 2018: Analyst
Shiyu Li, Jingdong Peng, Fang Chen, Ziyu Pan, Huanjun Peng, Yu Chen, Yan He, Xiang Wang
A highly sensitive and selective method of high performance liquid chromatography (HPLC) combined with resonance Rayleigh scattering (RRS) spectra was developed for the detection of three antihistamine drugs, including pyrilamine (PY), carbinoxamine (CAR) and tripelennamine (TRI). The three antihistamines were separated by a C18 column. The mobile phase contained 25% acetonitrile (ACN) and 75% phosphate buffered solution (pH 3.2) with the flow rate of 0.4 ml min-1 . In medium of Britton-Robinson (BR) buffer solution (pH 4...
August 16, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
Caitlin N Cain, Anna V Forzano, Sarah C Rutan, Maryanne M Collinson
The use of stationary phase gradients for liquid chromatography (LC) is a promising new strategy to allow for specific control over the selectivity of a separation by having a gradual change in the ligand density along the length of the column. Unfortunately, there have been very few, if any, methods to prepare continuous stationary phase gradients on traditional packed LC columns. In this work, destructive methodologies are used to create stationary phase gradients on commercial C18 columns by infusing trifluoroacetic acid (TFA) onto the column through controlled rate of infusion (CRI)...
July 27, 2018: Journal of Chromatography. A
Yu Zhang, Youzhong Wan, Bo Huo, Boyuan Li, Yue Jin, Xin Hu
Background: Products from Ficus carica have been used in traditional medicine to treat many diseases. This study aimed to analyze anticancer effects of extracts of F. carica leaves on the triple-negative breast cancer cell line MDA-MB-231. Materials and methods: The human breast cancer cell line MDA-MB-231 was used to evaluate effects of F. carica extracts. Effects of F. carica on cell viability were evaluated using MTT assays. Cell-cycle distribution was examined using cell-cycle analysis...
2018: OncoTargets and Therapy
Amal A El-Masry, Mohammed E A Hammouda, Dalia R El-Wasseef, Saadia M El-Ashry
Background: Green solvents such as microemulsion were used in the proposed method because they play a vital role in the analytical method's influence on the environment. Objective: A highly sensitive, specific, and validated stability-indicating eco-friendly green microemulsion liquid chromatography (MELC) method was developed for separation of the antihistaminic drug Azelastine HCl (AZL) from its degradation products with application to degradation kinetics. Methods: Chromatographic separation was operated on a C18 column with a microemulsion mobile phase, which consists of 0...
August 10, 2018: Journal of AOAC International
Mohie M K Sharaf El-Din, Khalid A M Attia, Mohamed W I Nassar, Mohamed M Y Kaddah
In this study, the chromatographic conditions for separation and determination of L- and D-lactic acid enantiomers by copper ligand exchange chromatography have been examined and optimized statistically using a response surface methodology (RSM). The chromatographic variables: copper sulfate, acetic acid and organic modifier were screened by operating a 2-level full factorial design (FFD). The significant effect of independent chromatographic variables was analyzed using the analysis of variance (ANOVA). Variables proved significant (p < 0...
November 1, 2018: Talanta
Yu-Xiu Yang, Qian Zhang, Qiao-Qiao Li, Zhi-Ning Xia, Hua Chen, Kai Zhou, Feng-Qing Yang
The passive membrane permeability of drugs may be potentially predicted by phospholipid-water sorption coefficient (KPLIPW ) through immobilized artificial membrane (IAM) chromatography. However, for predominantly ionized compounds, unexpected confounding electrostatic interaction would influence the accurate determination of KPLIPW , accompanied by the mobile phase with varied pH and ionic strength. In order to measure the intrinsic phospholipid-water sorption coefficient (KIAM,intr ) for diverse analytes, a mathematic model by characterizing the confounding electrostatic effects was developed in this study...
July 30, 2018: Journal of Chromatography. A
T Macé, E González-García, J Pradel, S Parisot, F Carrière, S Douls, D Foulquié, D Hazard
Animal robustness may be defined as a complex trait characterizing the ability of an individual to be adapted, productive and healthy under contrasted and fluctuating environmental situations. Such a trait is now considered an essential criterion in order to meet the more ambitious goals of farming sustainability. In ruminants, one of the key mechanisms via which robustness is expressed is the capacity to mobilize or restore body reserves (BR) to cope with the challenges of negative energy balances. The objectives of this work were i) to estimate the genetic parameters related to BR dynamics in ewes over successive production cycles and ii) to investigate BR management relationships between different physiological stages...
August 2, 2018: Journal of Animal Science
Kaja Przygońska, Jarosław Poznański, Ulrik H Mistarz, Kasper D Rand, Michał Dadlez
Oligomeric forms of the Aβ peptide represent the most probable neurotoxic agent in Alzheimer's disease. The dynamic and heterogeneous character of these oligomers makes their structural characterization by classic methods difficult. Native mass spectrometry, when supported by additional gas phase techniques, like ion mobility separation and hydrogen-deuterium exchange (IM-HDX-MS), enable analysis of different oligomers coexisting in the sample and may provide species-specific structural information for each oligomeric form populated in the gas phase...
2018: PloS One
Hao Chen, Lan Li, Shuai Song, Yan Du, Xiaoqin Jin, PeiPei Ding, Chenlin Shen, Xiaohui Huang
OBJECTIVE: This study aimed to conduct a sensitive, simple, and reliable liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the quantification of lacidipine in human plasma. MATERIALS AND METHODS: In this method, the plasma samples were extracted from human plasma using methanol as the precipitant and nisoldipine as internal standard (IS). The analytes were separated on a Phenomenex Luna C18 column (150 mm × 2.0 mm, 3 µm) at 40 °C using isocratic mobile phase consisting of 0...
August 6, 2018: International Journal of Clinical Pharmacology and Therapeutics
Pinxuan Huang, Weijun Kong, Sha Wang, Ruilin Wang, Jinghua Lu, Meihua Yang
OBJECTIVES: This study aimed to explore the residue levels of multiclass mycotoxins in medicinal and edible lotus seeds. METHODS: A rapid and reliable isotope-labelled internal standard-based UPLC-MS/MS method was developed and validated for sensitive and accurate analysis of multiclass mycotoxins including aflatoxins (AFB1 , AFB2 , AFG1 and AFG2 ), ochratoxin A (OTA), zearalenone (ZEN), deoxynivalenol (DON), fumonisins (FB1 and FB2 ), T-2 and HT-2 toxins in lotus seeds...
August 5, 2018: Journal of Pharmacy and Pharmacology
John A Hey, Petr Kocis, Jakub Hort, Susan Abushakra, Aidan Power, Martin Vyhnálek, Jeremy Y Yu, Martin Tolar
BACKGROUND: ALZ-801 is an oral, small-molecule inhibitor of beta amyloid (Aβ) oligomer formation in clinical development for Alzheimer's disease (AD). ALZ-801 is a prodrug of tramiprosate with improved pharmacokinetic properties and gastrointestinal tolerability. During clinical studies, we discovered that the primary metabolite of tramiprosate and its prodrug ALZ-801, 3-sulfopropanoic acid (3-SPA), is an endogenous molecule in the human brain and present in the cerebrospinal fluid (CSF) of patients with AD and other neurodegenerative brain diseases...
August 3, 2018: CNS Drugs
Keke Guo, Mijun Peng, Chaoying Tong, Shuyun Shi, Yuge Liu
Extraction is the most important step in the purification of bioactive compounds from natural products. This study interpreted a simple online extraction strategy coupled with high-speed counter-current chromatography for efficient extraction and purification of bioactive components from solid natural products. For online extraction strategy, 1.0 g of gound Mangnolia officinalis or Piper nigrum was loaded into a guard column, which was then positioned on the manual injection valve instead of the sample loop...
August 2, 2018: Journal of Separation Science
Biao Fu, Guijian Liu, Mei Sun, James C Hower, Md Manik Mian, Dun Wu, Ruwei Wang, Guangqing Hu
Emission of hazardous trace elements (HTEs) from energy production is receiving much attention due to concerns about the toxicity to the ecosystem and human health. This study presented new field measurement data on the HTEs partitioning behavior and size-segregated elemental compositions of gaseous particular matter (PM) generated from a commercial circulating fluidized bed (CFB) power plant. Mineralogical and morphological characteristics of combustion ash and PM2.5 (particle diameter less than 2.5 μm) were determined by X-ray diffractometer (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDS)...
July 20, 2018: Environmental Pollution
Jorge Ruíz-Olles, David K Smith
This paper explores macroscopic-scale diffusion of the molecular-scale building blocks of two-component self-assembled organogel nanofibres using a diffusion cell in which two different gels are in contact with one another. Both components of the 'solid-like' nanofibres (lysine peptide dendron acids and amines) can diffuse through these gels and across a gel-gel interface, although diffusion is significantly slower than that of a non-interactive additive in the 'liquid-like' phase of the gel. Amine diffusion was probed by bringing similar gels with different amines into contact...
July 7, 2018: Chemical Science
Haijiao Lu, Shengzhe Zhang, Jie Wu, Minjiang Chen, Mei-Chun Cai, Yujie Fu, Wenfeng Li, Jing Wang, Xiaojing Zhao, Zhuang Yu, Pengfei Ma, Guanglei Zhuang
PURPOSE: The induced death signals following oncogene inhibition underlie clinical efficacy of molecular targeted therapies against human cancer, and defects of intact cell apoptosis machinery often lead to therapeutic failure. Despite potential importance, other forms of regulated cell death triggered by pharmacological intervention have not been systematically characterized. EXPERIMENTAL DESIGN: Pyroptotic cell death was assessed by immunoblot, phase-contrast imaging, scanning electron microscopy, and flow cytometry...
July 30, 2018: Clinical Cancer Research: An Official Journal of the American Association for Cancer Research
S Sowjanya, Ch Devadasu
A reverse phase high-performance liquid chromatographic (RP-HPLC) method was developed and validated for simultaneous estimation of levamisole and albendazole in drug substance and in its combinational dosage form. The analysis was carried out using Inertsil ODS C18 (4.6 x 150 mm, 5 μ m) column, and the separation was carried out using a mobile phase containing a buffer of pH 3.5 and acetonitrile (70:30 v/v) pumped at a flow rate of 1.0 mL/min with variable wavelength UV-detection at 224 nm. Both the drugs were well resolved in the stationary phase and the retention times were 2...
2018: International Journal of Analytical Chemistry
Jian Liu, Feng Ji, Fengming Chen, Wei Guo, Minli Yang, Shengxiong Huang, Feng Zhang, Yongsheng Liu
A rapid, simple and environmentally friendly supercritical fluid extraction and supercritical fluid chromatography coupled to mass spectrometry (SFE-SFC-MS/MS) method has been developed for the analysis of nine phenolic compounds in garlic. Through the optimization of the SFE parameters using response surface methodology (RSM), 15 phenolic compounds were successfully extracted at 50 °C in 9 min with the addition of 30% methanol using a method that was automatic, efficient, green and prevented oxidation...
July 20, 2018: Journal of Pharmaceutical and Biomedical Analysis
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