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Ultra High Dilution

Rebecca Langhorn, Jacob D Yrfelt, Claus S Stjernegaard, Liselotte B Christiansen, Lisbeth H Olsen, Lise N Nielsen
BACKGROUND: Cardiac troponins are gold-standard biomarkers of myocardial injury. There is a need for validation of assays with higher availability and lower costs in veterinary medicine. OBJECTIVES: The primary aim of the present study was to perform an analytical validation of the IMMULITE 2000 TnI assay for use in dogs and cats. A secondary aim was to evaluate its agreement with the previously validated and sensitive Siemens ADVIA Centaur TnI-Ultra assay. METHODS: Intra- and inter-assay variation, detection limits, the linearity under dilution, and a sample addition study (modified spike-and-recovery analysis) were investigated to assess analytical performance in 15 canine and 15 feline serum samples...
December 11, 2018: Veterinary Clinical Pathology
F A Ibrahim, M E Fathy, H M Elmansi
Orciprenaline sulphate (ORP) is a direct-acting sympathomimetic with mainly beta-adrenoceptor stimulant activity. It is used as a bronchodilator in the management of reversible airway obstruction. For the first time, a rapid highly sensitive spectrofluorimetric method is described that is relied on measuring the fluorescence spectra of ORP at acidic pH and without addition of any chemical reagents. The relative fluorescence intensity was measured at 310 nm and after excitation at 224 nm. ORP native fluorescence was calibrated in both water and acetonitrile as diluting solvents...
December 11, 2018: Luminescence: the Journal of Biological and Chemical Luminescence
J Vitku, L Kolatorova, C Ricco, C Ferroud, O Hennebert, T Skodova, J Heracek, L Starka
7beta-hydroxy-epiandrosterone (7beta-OH-EpiA) is an endogenous androgen metabolite that has been shown to exert neuroprotective, anti-inflammatory and anti-estrogenic effects. However, to the best of our knowledge no information is available about this androgen steroid in relation to sperm quality. We analyzed 7beta-OH-EpiA in plasma and seminal plasma using a newly developed isotope dilution ultra-high performance liquid chromatography - mass spectrometry method. Validation met the requirements of FDA guidelines...
November 28, 2018: Physiological Research
Yibin Zheng, Delei Cai, Baifen Huang, Jianlong Han, Qing Chen, Jingshun Zhang, Jie Zhang, Xiaofeng Wang, Haitao Shen
In this paper, we established a method for the separation and detection of nine hydroxylated polychlorinated biphenyls in whole blood and urine samples using UPLC coupled with electrospray negative ionization tandem-mass spectrometry. Clean-up procedures involved a filtration step, and optimization involved a pretreatment step consisting of a simple liquid-liquid extraction, using hydrated silica-gel chromatography (5%). Nine hydroxylated polychlorinated biphenyls were separated on a UPLC HSS T3 column using a gradient elution program of 2 mmol ammonium formate aqueous solution (A), and methanol (B)...
November 27, 2018: Journal of Separation Science
Pin Liu, Jia Wei, Kun Yang, Isaac Yaw Massey, Jian Guo, Chengcheng Zhang, Fei Yang
Global proliferation of cyanobacterial blooms associated with climate change and eutrophication constitutes a serious environmental threat. In Hunan Province a freshwater pond located in Changsha City was found to contain high concentrations of cyanobacteria, however, the characteristics of these cyanobacteria at present are not known. This study thus aimed to isolate, identify the most common bloom-forming cyanobacteria in this region and determine the toxigenic characteristics of the predominant cyanobacteria...
November 15, 2018: Journal of Toxicology and Environmental Health. Part A
Xiao Su, Akihiro Kushima, Cameron Halliday, Jian Zhou, Ju Li, T Alan Hatton
The removal of highly toxic, ultra-dilute contaminants of concern has been a primary challenge for clean water technologies. Chromium and arsenic are among the most prevalent heavy metal pollutants in urban and agricultural waters, with current separation processes having severe limitations due to lack of molecular selectivity. Here, we report redox-active metallopolymer electrodes for the selective electrochemical removal of chromium and arsenic. An uptake greater than 100 mg Cr/g adsorbent can be achieved electrochemically, with a 99% reversible working capacity, with the bound chromium ions released in the less harmful trivalent form...
November 8, 2018: Nature Communications
T Zinn, A Homs, L Sharpnack, G Tinti, E Fröjdh, P A Douissard, M Kocsis, J Möller, Y Chushkin, T Narayanan
Successful implementation of the single-photon-counting Eiger 500k pixel array detector for sub-millisecond X-ray photon correlation spectroscopy (XPCS) measurements in the ultra-small-angle scattering region is reported. The performance is demonstrated by measuring the dynamics of dilute silica colloids in aqueous solvents when the detector is operated at different counter depths, 4, 8 and 12 bit. In the fastest mode involving 4 bit parallel readout, a stable frame rate of 22 kHz is obtained that enabled measurement of intensity-intensity autocorrelation functions with good statistics down to the 50 µs range for a sample with sufficient scattering power...
November 1, 2018: Journal of Synchrotron Radiation
Joseph H Kahl, Jennifer Gonyea, Susan M Humphrey, George W Hime, Diane M Boland
Since 2013, opioid-related deaths have increased in Miami-Dade County, FL due to fentanyl and fentanyl analogs in the local heroin supply. From 2014 to 2015, a near 600% increase in fentanyl and fentanyl analog-related deaths was observed, followed by another 200% increase in 2016. In addition to fentanyl, six fentanyl analogs were identified in this time period: β-hydroxythiofentanyl, acetyl fentanyl, furanyl fentanyl, carfentanil, butyryl fentanyl and para-fluoroisobutyryl fentanyl. As a result, an analytical method to quantify these compounds in postmortem biological fluids and tissues using solid-phase extraction with analysis by ultra high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS-MS) was developed and validated...
October 1, 2018: Journal of Analytical Toxicology
Zhipeng Wang, Yang Yang, Feng Zhang, Mingming Li, Jing Chen, Huan Man, Wei Jiang, Rui Zhang, Shouhong Gao, Wansheng Chen
Alpha-fluoro-beta-alanine (FBAL), the final metabolite of capecitabine, is a toxic compound excreting with urine. Magnesium isoglycyrrhizinate injection is a traditional Chinese medicine prescribed with capecitabine as a hepatoprotective agent. The purposes of this study are to develop an ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method for direct, efficient and sensitive determination of FBAL in urine and explore the influence of magnesium isoglycyrrhizinate on the excretion of FBAL in rat model...
October 18, 2018: Journal of Chromatography. B, Analytical Technologies in the Biomedical and Life Sciences
Hecson J Segat, Vinícia G Metz, Higor Z Rosa, Verônica T Dias, Raquel C S Barcelos, Geisa S Dolci, Marilise E Burger
INTRODUCTION: amphetamine (AMPH) is related to development of addiction, anxiety-like behaviors and impairments of memory after chronic use. In the current experiment, an ultra-high dilution (10-24 mg/mL) of AMPH was used, consisting of the AMPH isotherapic (AMPH-ISO), which can be used as a replacement therapy to treat AMPH addiction. AIM: To verify the influence of AMPH-ISO on toxicological aspects of AMPH addiction. METHODS: Rats received d,l-AMPH (4...
October 5, 2018: Neuroscience Letters
Erandi Hewawasam, Ge Liu, David W Jeffery, Beverly S Muhlhausler, Robert A Gibson
Oxylipins are biologically important lipid mediators that are derived enzymatically from polyunsaturated fatty acids (PUFA) and have a major role in regulating inflammatory processes. The currently available methods for measuring oxylipins from human biological samples have limitations, which restricts their use in large studies. We have developed a novel method for measuring 21 oxylipins from dried blood spot (DBS) using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) and stable isotope dilution analysis...
October 2018: Prostaglandins, Leukotrienes, and Essential Fatty Acids
Luciane Costa Dalboni, Cideli de Paula Coelho, Renata Rossettini Palombo Pedro, Michelle Sanchez Correia, Fabiana Rodrigues de Santana, Thayná Neves Cardoso, Sandra Augusta G Pinto, Anuska M Alvares-Saraiva, Maristela Dutra-Correa, Giovani B Peres, Carla Holandino, André Rossi, Amarilys de Toledo César, Silvia Waisse, Leoni Villano Bonamin
INTRODUCTION:  According to the "silica hypothesis" formulated to explain homeopathy, the information of starting materials would be transferred to cells by silica nanoparticles detached from the glassware walls by serial dilution and agitation through epitaxy. We compared the biological activity, electrical current and silicon microparticle content (by means of scanning electron microscopy/energy-dispersive X-ray spectroscopy) of high dilutions (HDs) of arsenic prepared in plastic and glass vials to investigate the role of silica in their biological effects in vitro...
October 5, 2018: Homeopathy: the Journal of the Faculty of Homeopathy
Majda Mekic, Gwendal Loisel, Wentao Zhou, Bin Jiang, Davide Vione, Sasho Gligorovski
A vertical wetted-wall flow-tube technique was used to explore the ionic strength effects at the air-water interface in mediating the sea-surface reaction between ozone (O3 ) and pyruvic acid (PA). The uptake coefficients of ozone on aqueous PA increase substantially with the concentrations of bromide (Br- ) ions, clearly indicating that the dry deposition of ozone could be significantly enhanced due to the presence of carbonyl compounds such as PA at the bromide-rich sea surface. Based on the observed uptake coefficients, the estimated deposition velocity of ozone (100 ppb) for a nanomolar range of PA concentrations is ∼1 × 10-3 m s-1 , which represents a significant contribution to the known deposition velocity of ozone at the sea surface...
October 17, 2018: Environmental Science & Technology
T Machida, Y Kohsaka, T Hanaguri
We describe the development and performance of an ultra-high vacuum scanning tunneling microscope working under combined extreme conditions of ultra-low temperatures and high magnetic fields. We combined a top-loading dilution refrigerator and a standard bucket dewar with a bottom-loading superconducting magnet to achieve 4.5 days operating time, which is long enough to perform various spectroscopic-imaging measurements. To bring the effective electron temperature closer to the mixing-chamber temperature, we paid particular attention to filtering out radio-frequency noise, as well as enhancing the thermal link between the microscope unit and the mixing chamber...
September 2018: Review of Scientific Instruments
Hong Zhang, Jia-Ming Jiang, Dan Zheng, Ming Yuan, Zhi-Ying Wang, Hong-Mei Zhang, Chang-Wu Zheng, Lian-Bo Xiao, Hong-Xi Xu
Here, time-decoupled comprehensive two-dimensional ultra-high liquid chromatography (UHPLC) coupled with an ion mobility (IM)-high resolution mass spectrometer (HRMS) was established and used to analyze ginsenosides from the main roots of white ginseng (WG) and red ginseng (RG), which enabled the separation of complex samples in four dimensions (2D-LC, ion mobility, and mass spectrometry). The incompatibility of mobile phases, dilution effect, and long analysis time, which are the main shortcomings of traditional comprehensive 2D-LC methods, were largely avoided in this newly established 2D-UHPLC method...
September 21, 2018: Journal of Pharmaceutical and Biomedical Analysis
Diogo La Rosa Novo, Julia Eisenhardt Mello, Filipe Soares Rondan, Alessandra Schneider Henn, Paola Azevedo Mello, Marcia Foster Mesko
In this work, an analytical method for bromine and iodine determination in human saliva was proposed. A simple protocol based on centrifugation and direct analysis of supernatant by inductively coupled plasma mass spectrometry (ICP-MS) was investigated. Although this method was feasible for bromine determination, iodine was partially present in the supernatant and an agreement about 54% with reference value was obtained. In addition, microwave-induced combustion (MIC) and microwave-assisted dissolution were also evaluated...
January 1, 2019: Talanta
Yongqing Wen, Xuemei Yuan, Feng Qin, Longshan Zhao, Zhili Xiong
Determination of amino acids in biofluids is a challenging task because of difficulties deriving from their high polarity and matrix interference. A simple, reliable and high-throughput hydrophilic interaction UHPLC-MS/MS method was developed and validated for the rapid simultaneous determination of 19 free amino acids in rat plasma and urine samples in this paper. Hydrophilic method with a Waters Acquity UPLC BEH Amide column (100 × 2.1 mm,1.7 μm) was used with a gradient mobile phase system of acetonitrile and water both containing 0...
September 20, 2018: Biomedical Chromatography: BMC
E Hakme, A Lozano, S Uclés, M M Gómez-Ramos, A R Fernández-Alba
Spices are known as difficult matrices that contain variable amounts of fats, piperine or many other matrix constituents. The increasing sensitivity of new GC-MS/MS platforms opens new approaches to analyze pesticide residue in complex matrices such as spices, by sample dilution. The aim of this work is to develop and validate an effective multiresidue method for the analysis of pesticide residues in spices by GC-MS/MS. In this paper, we highlight the importance of reducing matrix interferences generated from co-extractive components of spices...
October 26, 2018: Journal of Chromatography. A
Rashmi Ranjan Suna, Nirmal K Viswanathan
Development of alternate techniques to polarimetry for the measurement of weak optical rotation, with improved sensitivity, is becoming increasingly important as one understands the role of chirality in drug design and synthesis and the fundamentals of chiral light-matter interaction. We demonstrate here an optical amplification scheme using a spin-phase-gradient beam to measure ultra-small optical rotation angle (4 mdeg), with a sensitivity of 220 μdeg/μm, due to dilute (mg/mL) dextro-rotatory sugar solution...
September 15, 2018: Optics Letters
Peng Zhou, Qian Huang, Liqun Ouyang, Zheng Wang, Peng Meng, Ming Dai, Ying Wang
A method based on ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was established for the determination of fipronil and its metabolites in feeds. Sodium chloride was added to the samples after the ultrasonic extraction of pure water and acetonitrile, and then cleaned up by the QuEChERS method. The target analytes were separated on a Waters HSS T3 C18 column using methanol and water as mobile phases with gradient elution, and detected by a MS/MS system under negative electro-spry ionization (ESI- ) and the multiple reaction monitoring (MRM) mode...
July 8, 2018: Se Pu, Chinese Journal of Chromatography
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