Tea is the second most consumed beverage in the world and its consumption has been associated with numerous potential health benefits. Factors such as fermentation methods, geographical origin and season can affect the primary and secondary metabolite composition of tea. In this study, a hydrophilic interaction liquid chromatography (HILIC) method coupled to high resolution mass spectrometry in both positive and negative ionisation modes was developed and optimised. The method when combined with principal component analysis to analyse three different types of tea, successfully distinguished samples into different categories, and provided evidence of the metabolites which differed between them. The accurate mass and high resolution attributes of the mass spectrometric data were utilised and relative quantification data were extracted post-data acquisition on 18 amino acids, showing significant differences in amino acid concentrations between tea types and countries. This study highlights the ...
A method for the analysis of dextran-1 has been developed using hydrophilic interaction liquid chromatography (HILIC) with charged corona aerosol detection (CCAD) as a potential alternative to the size exclusion chromatography method described in the European Pharmacopoeia (EP). Click to read more...
Differential mobility spectrometry for improved selectivity in hydrophilic interaction liquid chromatography-tandem mass spectrometry analysis of paralytic shellfish toxins
article{167611, author = {Van de Wiele, Mieke and De Wasch, Katia and VERCAMMEN, J and COURTHEYN, D and De Brabander, Hubert and Impens, Sandra}, issn = {0021-9673}, journal = {JOURNAL OF CHROMATOGRAPHY A}, language = {eng}, number = {2}, pages = {203--209}, title = {Determination of 16 beta-hydroxystanozolol in urine and faeces by liquid chromatography-multiple mass spectrometry.}, volume = {904}, year = {2000 ...
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Simultaneous determination of β-hydroxybutyrate and β-hydroxy-β-methylbutyrate in human whole blood using hydrophilic interaction liquid chromatography electrospray tandem mass ...
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A recently developed stable isotope dilution liquid chromatography-multiple reaction/mass spectrometry method to quantify focal adhesion kinase (FAK) activation loop phosphorylation was used to study endogenous Src kinase activity. This revealed that bis-phosphorylated pTyr576/Tyr577-FAK was a biomarker of Src activity and inactivation in vitro and in cell culture. Mouse embryonic fibroblasts (MEFs) expressing endogenous Src family kinases contained 65% unmodified Tyr576/Tyr577, 33% mono-phosphorylated-pTyr576-FAK, and 6% bis-phosphorylated-pTyr576/pTyr577-FAK. In contrast, MEFs expressing oncogenic Y529FSrc contained 38% unmodified Tyr576/Tyr577-FAK, 29% mono-phosphorylated-pTyr576-FAK, and 19% bis-phosphorylated-pTyr576/pTyr577-FAK. This new method has made it possible to accurately determine the absolute amounts of FAK phosphorylation that occur after Src inhibition in cell culture and in vitro with increasing concentrations of the Src inhibitor ...
Mitochondrial dysfunction plays a role in a wide range of diseases resulting in an enormous public health burden. The goal of this thesis is to identify metabolic pathways that are disrupted in response to mitochondrial insults. A large proportion of this work is based on the generation of stable isotope labelled metabolites to allow for the rigorous quantification of intracellular metabolites by liquid chromatography-mass spectrometry. Once developed, this methodology was employed in cell culture models initially to characterize an unidentified acyl-CoA thioester induced by propionate metabolism. This novel pathway was identified as the direct formation of 2-methyl-2-pentenoyl-CoA, and using isotopic labeling by metabolic precursors served as a critical component to this pathway elucidation. These same techniques were then applied to studying rotenone, a mitochondrial complex I inhibitor associated with Parkinsonâ??s disease. Previous work by our group has shown that rotenone inhibits components of
PubMed Central Canada (PMC Canada) provides free access to a stable and permanent online digital archive of full-text, peer-reviewed health and life sciences research publications. It builds on PubMed Central (PMC), the U.S. National Institutes of Health (NIH) free digital archive of biomedical and life sciences journal literature and is a member of the broader PMC International (PMCI) network of e-repositories.
In a preliminary study in healthy subjects, the investigators determined the pharmacokinetic and pharmacodynamic of enteric-coated acetylsalicylic acid (ASA) (Adiro 100 mg, Bayer), and the variability (coefficient of variation), accuracy and precision of a novel biomarker of ASA action, i.e., quantification of the extent of COX-1 acetylation at serine-529, using a stable isotope dilution liquid chromatography multiple reaction monitoring/mass spectrometry (LC-MS) technique.. Now, the investigators will perform a clinical study in individuals undergoing Colorectal cancer (CRC) to validate the hypothesis that that low-dose ASA given once daily is acting primarily by selectively acetylating platelet COX-1 and suppressing its activity throughout the 24-hour dosing interval. In contrast, it is expected that the inhibitory effect on extra-platelet sources of COX-1 will be short-lasting, if any, affecting only partially COX-1, and this effect will be completely reversed at 24 hours after dosing. This ...
A novel bioanalytical method was developed and validated for the quantitative determination of erlotinib in human plasma by using the supported liquid extraction (SLE) sample cleanup coupled with hydrophilic interaction liquid chromatography and tandem mass spectrometric detection (HILIC-MS/MS). The SLE extract could be directly injected into the HILIC-MS/MS system for analysis without the solvent evaporation and reconstitution steps. Therefore, the method is simple and rapid. In the present method, erlotinib-d6 was used as the internal standard. The SLE extraction recovery was 101.3%. The validated linear curve range was 2 to 2,000 ng/mL based on a sample volume of 0.100-mL, with a linear correlation coefficient of | 0.999. The validation results demonstrated that the present method gave a satisfactory precision and accuracy: intra-day CV | 5.9% (
Protein recovery is crucial for shotgun metaproteomics to study the in situ functionality of microbial populations from complex biofilms but still poorly addressed by far. To fill this knowledge gap, we systematically evaluated the sample preparation with extraction buffers comprising four detergents for the metaproteomics analysis of a terephthalate-degrading methanogenic biofilm using an on-line two-dimensional liquid chromatography tandem mass spectrometry (2D-LC-MS/MS) system. Totally, 1018 non-repeated proteins were identified with the four treatments. On the whole, each treatment could recover the biofilm proteins with specific distributions of molecular weight, hydrophobicity, and isoelectric point. The extraction buffers containing zwitterionic and anionic detergents were found to harvest the proteins with better efficiency and quality, allowing identification up to 76.2% of total identified proteins with the LC-MS/MS analysis. According to the annotation with a relevant metagenomic
Lin XH,WangQuancai,Yin PY,et al. A method for handling metabonomics data from liquid chromatography mass spectrometry: combinational use of support vector machine recursive feature elimination, genetic algorithm and random forest for feature selection[J]. Metabolomics,2011,4(待补充):549 ...
Agilent Technologies Inc. announced analyses of carbamates and phenyl ureas using liquid chromatography/mass spectrometry (LC/MS). The sources for these tes
Interest in chromatography using hydrophilic interaction liquid chromatography (HILIC) has continued to build in recent years. Although HILIC chromatography is known to provide valuable retention and selectivity of polar compounds and provide highly compa...
Currently, statins are the only drugs acting on the mammalian isoprenoid pathway. The mammalian genes in this pathway are not easily amenable to genetic manipulation. Thus, it is difficult to study the effects of the inhibition of various enzymes on the intermediate and final products in the isoprenoid pathway. In fission yeast, antifungal compounds such as azoles and terbinafine are available as inhibitors of the pathway in addition to statins, and various isoprenoid pathway mutants are also available. Here in these mutants, treated with statins or antifungals, we quantified the final and intermediate products of the fission yeast isoprenoid pathway using liquid chromatography-mass spectrometry/mass spectrometry. In hmg1-1, a mutant of the gene encoding 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR), ergosterol (a final sterol product), and squalene (an intermediate pathway product), were decreased to approximately 80% and 10%, respectively, compared with that of wild-type cells. Consistently
Methylation aberrations play an important role in many metabolic disorders including cancer. Methylated metabolites are direct indicators of metabolic aberrations, and currently, there is no liquid chromatography-mass spectrometry (LC-MS) based method available to cover all classes of methylated metabolites at low detection limits. In this study, we have developed a method for the detection of methylated metabolites, and its biological application. In this approach, we used a HILIC based HPLC method combined with MS to measure methylated organic acids, amino acids, and nucleotides. These metabolites were separated from each other by their hydrophobic interactions and analyzed using a targeted metabolomics approach by single reaction monitoring in positive and negative modes of electrospray ionization. These metabolites were quantified, and the interday reproducibility was ,10% relative standard deviation. Furthermore, by applying this method, we identified high levels of methylated metabolites ...
Polysaccharides from Baizhu were separated by preparative hydrophilic interaction liquid chromatography on an XAmide column and its components were characterised as inulin-type polysaccharides with structures of alpha-D-glucopyranosyl-[-(1 -> 2) -beta-D-fructofuranosyl-](n-1)-(1 -> 2) -beta-D-fructofuranoside (n=3-20) by a combinatory application of electrospray-ionisation mass spectrometry, nuclear magnetic resonance and IR, as well as the chemical analysis of monosaccharide composition. In addition, the contents of nystose and 1F-fructofranosylnystose in the crude and purified Baizhu polysaccharides were determined to be 5.81%, 4.92% and 0.70%, 0.84% (w/w), respectively. In addition, MTT assay indicated that the Baizhu polysaccharides could effectively promote spleen lymphocyte transformation for the enhancement of organism immunity. It is for the first time that inulin-type polysaccharides were discovered in Baizhu and its immuno-enhancing activity was reported, which is a vigorous evidence ...
Immunoassay has been used to measure the blood concentration of drugs, steroids, and vitamin D. However, the immunoassay methods have limitations related to the differences of the methods, variation in the reagents, sensitivity, and specificity. Recently liquid chromatograph mass spectrometers (LC/MS/MS) are being used to improve analytical accuracy and precision based on its superior specificity. On the other hand, in the analysis of biological samples like serum by LC/MS/MS, sample preparation is required to carry out protein precipitation and sample dilution. These procedures cause a risk of variations and mistakes, depending on the operators procedure. In this article, the validation of 25-OH vitamin D2/D3 and steroids in serum using a fully automated sample preparation LC/MS/MS system is described.. Keywords: Sample preparation, Vitamin D, Steroids, LC/MS/MS. ...
LIQUID CHROMATOGRAPHY-MASS SPECTROMETRY FOR THE STUDY OF ARACHIDONIC ACID METABOLITES Xiaojing Liu Ian A. Blair, PhD Arachidonic acid (AA) oxidation metabolism has been an important research topic for decades, and numerous oxidation products as well as enzymes involved in AA metabolism together with their downstream metabolites have been identified, although unknown pathways still remain to be characterized. In the present a study a new AA metabolite, 11-oxo-eicosatetraenoic acid (ETE), generated from a major product of cyclooxygenase (COX-2), 11(R)-hydroxyeicosatetraenoic acid (HETE), through 15-hydroxyprostaglandine dehydrogenase (15-PGDH)-mediated oxidation. 11-Oxo-ETE was found to have an anti-proliferative effect on human umbilical vein endothelial cells (HUVECs), with a similar IC50 to a well- known anti-inflammatory mediator, 15-deoxy-12,14-prostaglandin J2 (15d-PGJ2). It was also found that 11-oxo-ETE could be inactivated through the glutathione-S-transferase (GST)/glutathione (GSH) pathway
Fibroblast growth factor 23 (FGF23) is a bone-derived hormone that controls blood phosphate levels by increasing renal phosphate excretion and reducing 1,25-dihydroxyvitamin D3 [1,25(OH)2D] production. Disorders of FGF23 homeostasis are associated with significant morbidity and mortality, but a fundamental understanding of what regulates FGF23 production is lacking. Because the kidney is the major end organ of FGF23 action, we hypothesized that it releases a factor that regulates FGF23 synthesis. Using aptamer-based proteomics and liquid chromatography-mass spectrometry-based (LC-MS-based) metabolomics, we profiled more than 1600 molecules in renal venous plasma obtained from human subjects. Renal vein glycerol-3-phosphate (G-3-P) had the strongest correlation with circulating FGF23. In mice, exogenous G-3-P stimulated bone and bone marrow FGF23 production through local G-3-P acyltransferase-mediated (GPAT-mediated) lysophosphatidic acid (LPA) synthesis. Further, the stimulatory effect of G-3-P ...
The Sustainable Environment Research Centre (SERC) undertakes national and world-leading research into waste treatment and the sustainable production of energy from waste and grown biomass. To achieve this, considerable investment has been made into the facilities available to researchers and students.. Waste Water Treatment and Fermentative Hydrogen Production Laboratory. This is a dedicated laboratory for the development and testing of lab scale bio-reactors. Research undertaken includes the optimisation of hydrogen and methane production from various waste substrates, and has been key to the successful development of several field-scale systems.. Ultra Performance Liquid Chromatography Laboratory. SERC is one of only a handful of sites in the UK to be undertaking environmental research using state-of-the-art Ultra Performance Liquid Chromatography / Mass Spectrometry (UPLC-MS). This analytical method provides highly accurate results to nano-gram concentrations. The equipment is currently ...
Dittmar, T. , Whitehead, K. , Minor, E. C. and Koch, B. (2007): Tracing terrigenous dissolved organic matter and its photochemical decay in the ocean by using liquid chromatography/mass spectrometry , Marine chemistry ...
LC/MS analysis of the chimeric OMT reaction products using laudanosoline as a substrate. Upper panel; OMT reactions and their predicted ions in LC/MS analysis.
...With the advent of liquid chromatography/ mass spectrometry and inform... Abstract ... The Q TRAP instrument is based on a triple quadrupole ion path and is... ...,Simultaneously,characterizing,and,quantifying,chloramphenicol,and,its,metabolite,using,LC/MS/MS,biological,advanced biology technology,biology laboratory technology,biology device technology,latest biology technology
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This application brief demonstrate the unique ability of charged surface hybrid (CSH Technology) C18 to produce high peak capacity peptide separations at high mass loads in nanoLC chromatography
Liquid chromatography with tandem mass spectrometry (LC-MS/MS) based quantitative proteomics provides the relative different protein abundance in healthy and disease-afflicted patients, which offers the information for molecular interactions, signaling pathways, and biomarker identification to serve the drug discovery and clinical research. Typical analysis workflow begins with the peptide feature detection and intensity calculation from LC-MS map. We are the first to propose a deep learning based model, DeepIso, that combines recent advances in Convolutional Neural Network (CNN) and Recurrent Neural Network (RNN) to detect peptide features of different charge states, as well as, estimate their intensity. Existing tools are designed with limited engineered features and domain-specific parameters, which are hardly updated despite a huge amount of new coming proteomic data. On the other hand, DeepIso consisting of two separate deep learning based modules, learns multiple levels of representation ...
Due to the high prescription of antidepressants and their frequent involvement in clinical and forensic intoxications, reliable analytical techniques for identification and quantification of these...
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List of Authors: J. Caixach, C. Flores, L. Spoof, J. Meriluoto, W. Schmidt, H. Mazur-Marzec, A. Hiskia, T. Kaloudis, A. Furey ...
Easy-to-use data acquisition and processing for LC-MS/MS analysis with software features to improve productivity in the clinical laboratory.
We are skilled in the development of analytical methods for determination of trace amounts of tracked impurities. For our customers we usually develop methods for assessment of toxic impurities at levels much below those demanded by corresponding regulatory authorities. Often we deal with systems where the target components are susceptible to decomposition or can react easily with the active ingredient or sample matrix. Despite these challenges, we continue to succeed with the development of such methods. For this purpose we use LC/MS (HPLC 2695 Alliance(Waters)/LTQ (Thermo-Finnigan)) or GC/MS (7890A/5975C(Agilent Technologies)) technique. Routinely, we are able to achieve a sensitivity at ppm levels on both these systems which is usually sufficient for most pharmaceutical applications.. When necessary, we benefit from cooperation with our bioanalytical department. There we may use several (mostly triple-quadrupole) LC/MS instruments in tandem offering a sensitivity in the order of units ...
Me Time Tag, o leapsa creata de Essie Button si Amelia ce contine 10 intrebari legate preferintele pentru "me-time", timpul pe care ni-l acordam pentru noi.
Citation: Pawlosky, R.J., Flanagan, V.P., Novotny Dura, J. 2000. A sensitive procedure for the study of beta-carotene-d8 metabolism in humans using liquid chromatography-mass spectrometry. Journal of Lipid Research. 41:1027-1031. Interpretive Summary: This report describes the development of a robust method for studying the metabolism of (stable hydrogen) deuterium- labeled-Beta-carotene in humans using liquid chromatography and mass spectrometry. Deuterium-labeled-Beta-carotene was extracted from human blood and injected onto a liquid chromatograph. The limit of detection was about 0.3 ng for deuterium-labeled-Beta-carotene. The compound was quantified over a concentration range of two orders of magnitude using an internal standard. The overall coefficient of variance (CV) for determining the concentration of deuterium-labeled-Beta-carotene from blood was 2.4%. Using this method, the concentration of deuterium-labeled-Beta-carotene was determined in the plasma of a subject who had consumed a ...
Two disparate paths can lead to increased performance in mass spectrometric analysis. Improvements in fundamental parameters of instrument performance can be achieved through optimized interface design, improvements in ion source and analyzer efficiency, and enhanced detector performance. Increased performance also can be achieved through a better sampling protocol, or through better chromatographic performance. Alternatively, because we are clever chemists, we might choose to alter the chemical and physical characteristics of the sample itself, however collected, to achieve a more complete transport through the sample purification/selection/chromatographic process, and to achieve better ionization through enhanced sensitivity or selectivity. This second path involves a change in either the physical or chemical form of the sample. A change in the chemical form of the sample is sample derivatization, which is the focus of this column.
Anthias Consulting Trainer and Consultant Dr Giles Edwards is presenting a week-long course on liquid chromatography-mass spectrometry (LC-MS) in Nairobi, Kenya.
BioAssay record AID 755005 submitted by ChEMBL: Permeability from basolateral to apical side of human Caco2 cells at 10 uM after 30 to 90 mins by LC-MS/MS analysis.
Agilent Technologies has introduced the latest addition to its portfolio of solutions for biopharmaceutical labs the Agilent 6545XT AdvanceBio LCQ-TOF MS system. Optimized to address analytical workflows commonly used in biopharma, the new LCQ-TOF MS system combines high-performance liquid chromatography HPLC with robust quadrupole time-of-flight...
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Question - Suffering from IBS. Recurring digestion problem. Continued drinking with medication. Disease worsen. Surviving on liquid diet and probiotics. Medication? . Ask a Doctor about uses, dosages and side-effects of Ofloxacin, Ask a Gastroenterologist
BANTAN POLAK, Tjaša, MITROVIĆ, Bojan, MILAČIČ, Radmila. The use of fast protein liquid chromatography with ICP-OES and ES-MS-MS detection for the determination of various forms of aluminium in the roots of Chinese cabbage. Anal. chim. acta. [Print ed.], 2005, vol. 540, no. 1, str. 83-89 ...
Sigma-Aldrich offers abstracts and full-text articles by [Atsuhiko Toyama, Hidewaki Nakagawa, Koichi Matsuda, Nobuhisa Ishikawa, Nobuoki Kohno, Yataro Daigo, Taka-Aki Sato, Yusuke Nakamura, Koji Ueda].
The AC Extraction Plate from Tecan is an automation-friendly solution designed to streamline sample preparation for LC-MS analysis of small molecules.
Consider how ion pairing shields proteinaceous residues from interacting with the amide stationary phase in large molecule HILIC separations.
Li Y (2007) CST Curation Set: 2888; Year: 2007; Biosample/Treatment: cell line, A549/untreated &,, TSA; Disease: lung cancer; SILAC: -; Specificities of Antibodies Used to Purify Peptides prior to LCMS: acK ...
Zhou J (2009) CST Curation Set: 6540; Year: 2009; Biosample/Treatment: cell line, MEF/untreated; Disease: -; SILAC: -; Specificities of Antibodies Used to Purify Peptides prior to LCMS: mR ...
TY - JOUR. T1 - Optimized extraction of phospholipids and lysophospholipids for nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry. AU - Byeon, Seul Kee. AU - Lee, Ju Yong. AU - Moon, Myeong Hee. PY - 2012/1/21. Y1 - 2012/1/21. N2 - The efficiencies of four different methods for the extraction of phospholipids (PLs) and lysophospholipids (LPLs) from human plasma samples were examined by comparing extraction recovery values using nanoflow liquid chromatography-electrospray ionization-mass spectrometry (nLC-ESI-MS). For recovery measurements, six PL and six LPL standards of different head groups were spiked into a human plasma sample, and the peak areas of each individual species after extraction were measured from the chromatograms of the nLC-ESI-MS runs. Recovery was calculated by comparing the peak area of an extracted standard species with that of the same species spike after extraction of the same plasma sample. For lipid extraction, four different extraction ...
Florentina Laura Chiriac, Iuliana Paun, Florinela Pirvu, Luoana Florentina Pascu, Marcela Niculescu, Toma Galaon - Liquid Chromatography Tandem Mass Spectrometry Method for Ultra-Trace Analysis of Organic UV Filters in Environmental Water Samples
TY - JOUR. T1 - Comparison of gas chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry methods to quantify α-tocopherol and αtocopherolquinone levels in human plasma. AU - Mottier, Pascal. AU - Gremaud, Eric. AU - Guy, Philippe A.. AU - Turesky, Robert J.. PY - 2002/2/1. Y1 - 2002/2/1. N2 - Two mass spectrometric methods were established for the quantitative analyses of α-tocopherol (TH) and its oxidation product α-tocopherolquinone (TQ) in human plasma. Both methods make use of isotopically labeled internal standards of different levels of deuteration (d3-TH and d6-TQ). Plasma (100 μl) was saponified in the presence of a mixture of antioxidants, and then TH and TQ were extracted with hexane. With the GC-MS method, the analytes were first converted into O-trimethylsilyl derivatives before analysis in the selective ion monitoring mode. The derivatization procedure led to the quantitative conversion of TQ into the O-trimethylsilyl derivative of ...
We have demonstrated an on-line laser ablation sampling system and coupling of the system to liquid chromatography (LC) using an infrared (IR) laser to ablate and transfer materials into a flowing solvent stream. With this approach, samples are depos
RATIONALE Neonicotinoids (NNIs) are the fastest expanding group of pesticides in the world over the last two decades; however, they may be a significant contributing factor to bee mortality. The widespread use of NNIs makes it critical to monitor their residuals in the environment. Published methods for NNI analysis are mainly focused on agricultural and food products, and many of them only measured a portion of the commercially available NNIs. METHODS Utilizing a biphenyl stationary-phase column, a sensitive liquid chromatography/tandem mass spectrometry (LC/MS/MS) method was developed to determine eight NNIs, including acetamiprid, clothianidin, dinotefuran, flonicamid, imidacloprid, nitempyram, thiacloprid and thiamethoxam in environmental water. Two multiple reaction monitoring (MRM) transitions were monitored for each compound to ascertain true positive identification. Isotope-labelled NNIs, d3-acetamiprid, d3-clothianidin, d4-imidacloprid and d3-thiamethoxam, were used to compensate for
Abstract: A liquid chromatography tandem mass spectrometry method was developed for quantifying ten cannabinoids in oral fluid (OF). This method utilizes OF collected by the Quantisal device and concurrently quantifies cannabinol (CBN), cannabidiol (CBD), Δ9-tetrahydrocannabinol (THC), 11-hydroxy-Δ9-THC (11-OH-THC), 11-nor-9-carboxy-Δ9-THC (THC-COOH), 11-nor-9-carboxy-Δ9-THC glucuronide (THC-COOH-gluc), Δ9-THC glucuronide (THC-gluc), cannabigerol (CBG), tetrahydrocannabiverin (THCV), and Δ9-tetrahydrocannabinolic acid A (THCA-A). Solid phase extraction was optimized using Oasis Prime HLB 30 mg 96-well plates. Cannabinoids were separated by liquid chromatography over a BEH C18 column and detected by a Waters TQ-S micro tandem mass spectrometer. The lower limits of quantification (LLOQ) were 0.4 ng/mL for CBN, CBD, THC, 11-OH-THC, THC-gluc, and THCV; and 1.0 ng/mL for THC-COOH, THC-COOH-gluc, CBG and THCA-A. Linear ranges extended to 2000 ng/mL for THC and 200 ng/mL for all other analytes. ...
TY - JOUR. T1 - Analysis of metribuzin and its metabolites in livestock products and seafoods by liquid chromatography-tandem mass spectrometry. AU - Kai, Shigemi. AU - Akaboshi, Takeshi. AU - Waki, Masumi. AU - Fuzimaki, Teruhisa. AU - Kanazawa, Hideko. PY - 2011/2. Y1 - 2011/2. N2 - A method for simultaneous determination of metribuzin (MET) and three metribuzin metabolites in livestock products and seafoods by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed. MET and its metabolites were extracted from a sample with acetonitrile, followed by InertSepC18 and BondElut SAX cartridge cleanup. The LC separation was performed on a C18 column using 0.01 mol/L ammonium formate-acetonitrile-methanol (70 : 21 : 9) as the mobile phase and MS detection with both positive and negative ion electrospray ionization. The mean recoveries from 10 livestock products and seafoods were generally ,60%, and the relative standard deviations were ,20%.. AB - A method for simultaneous ...
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TY - JOUR. T1 - Validation of a high throughput method for serum/plasma testosterone using liquid chromatography tandem mass spectrometry (LC-MS/MS). AU - Singh, Ravinder Jit. PY - 2008/12/12. Y1 - 2008/12/12. N2 - Testosterone, the major androgenic hormone in humans, is commonly measured to aid in the diagnosis of clinical conditions related to its excess or deficiency. In addition, testosterone measurements are used to monitor testosterone replacement-, or antiandrogen therapy. Most commonly, automated direct immunoassays have been used to measure testosterone in human serum. Their advantage compared with other methodologies, lies in high- and rapid sample throughput with minimal human intervention. However, many automated testosterone immunoassays suffer from poor accuracy at the low concentration levels (,50 ng/dL) seen in women and children, or in men undergoing anti-androgen therapy. Our objective was to develop a LC-MS/MS method which measures testosterone in human serum while fulfilling ...
The obligate intracellular lifestyle of Plasmodium falciparum and the difficulties in obtaining sufficient amounts of biological material have hampered the study of specific metabolic pathways in the malaria parasite. Thus, for example, the pools of sugar nucleotides required to fuel glycosylation reactions have never been studied in-depth in well-synchronized asexual parasites or in other stages of its life cycle. These metabolites are of critical importance, especially considering the renewed interest in the presence of N-, O-, and other glycans in key parasite proteins. In this work, we adapted a liquid chromatography tandem mass spectrometry (LC-MS/MS) method based on the use of porous graphitic carbon (PGC) columns and MS-friendly solvents to quantify sugar nucleotides in the malaria parasite. We report the thorough quantification of the pools of these metabolites throughout the intraerythrocytic cycle of P. falciparum The sensitivity of the method enabled, for the first time, the targeted ...
Liquid chromatography tandem mass spectrometry is one of the most specific techniques available in clinical laboratories. In the past, immunoassays were the primary methodology for analysis of steroids in biological samples because they are rapid and easy to perform. However, these methods were shown to suffer from the lack of specificity for measuring many of the diagnostically important steroids. LC-MS/MS overcomes many of the limitations of immunoassays, enhances diagnostic utility of the testing, and expands diagnostic capabilities in endocrinology. In addition to the superior quality of the measurements, LC-MS/MS allows high throughput testing using small sample volume with minimal sample preparation, and frees the laboratory from dependence on suppliers of assay specific reagents. LC-MS/MS is being widely employed for routine measurement of steroids, and the methodology plays an important role in the standardization and harmonization of measurements among clinical laboratories.. ...
A stereoselective, sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MSMS) method for the determination of R-acenocoumarol and S-acenocoumarol in human plasma was developed and validated at IPRC bioanalytical labs. The procedure involved solid phase extraction of both enantiomers and their corresponding internal standard. The chromatographic separation was accomplished employing a chiral column and proper mobile phase. Detection was carried out using Waters Micromass® Quattro Premier mass spectrometer in multiple reaction monitoring (MRM) mode using turbo ion spray with negative ionization. The method was validated over a linear range of 0.40 - 40.00 ng/ml for R-acenocoumarol and 0.20 - 20.00 ng/ml for the S-acenocoumarol. Method validation covered different parameters such as linearity, accuracy, precision and stability. The method was successfully applied for the determination of R and S-acenocoumarol in plasma samples of 28 healthy subjects who participated in a pharmacokinetics
TY - JOUR. T1 - Reference ranges for testosterone in men generated using liquid chromatography tandem mass spectrometry in a community-based sample of healthy nonobese young men in the framingham heart study and applied to three geographically distinct cohorts. AU - Bhasin, Shalender. AU - Pencina, Michael. AU - Jasuja, Guneet Kaur. AU - Travison, Thomas G.. AU - Coviello, Andrea. AU - Orwoll, Eric. AU - Wang, Patty Y.. AU - Nielson, Carrie. AU - Wu, Frederick. AU - Tajar, Abdelouahid. AU - Labrie, Fernand. AU - Vesper, Hubert. AU - Zhang, Anqi. AU - Ulloor, Jagadish. AU - Singh, Ravinder. AU - DAgostino, Ralph. AU - Vasan, Ramachandran S.. PY - 2011/8/1. Y1 - 2011/8/1. N2 - Context: Reference ranges are essential for partitioning testosterone levels into low or normal and making the diagnosis of androgen deficiency. We established reference ranges for total testosterone (TT) and free testosterone (FT) in a community-based sample of men. Methods: TT was measured using liquid chromatography ...
An improved method for determining levels of levosulpiride in human plasma using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and validated. The protein precipitation method was used for plasma sample preparation. Levosulpiride and an internal standard (IS) were isocratically separated on a UPLC BEN C(18) column with a mobile phase of ammonium formate buffer (1 mM, adjusted to pH 3 with formic acid) and acetonitrile (60:40, v/v). MS/MS detection was performed by monitoring the parent -, daughter pair of levosulpiride and the IS at m/z 342 -, 112 and 329 -, 256, respectively. The method was linear from 2.5 to 200 ng/mL and exhibited acceptable precision and percent recovery. The method was successfully demonstrated in pharmacokinetic and bioequivalence studies of two levosulpiride oral formulations administered to healthy volunteers. When compared to the previous LC-MS methods, the proposed method is faster, well-validated, and uses lesser plasma ...
TY - JOUR. T1 - Effect of ionization modifiers on the simultaneous analysis of all classes of phospholipids by nanoflow liquid chromatography/tandem mass spectrometry in negative ion mode. AU - Bang, Dae Young. AU - Lim, Sangsoo. AU - Moon, Myeong Hee. PY - 2012/6/1. Y1 - 2012/6/1. N2 - The effect of ionization modifiers added to the mobile phase of nanoflow liquid chromatography-tandem mass spectrometry (nLC-ESI-MS 3) on the simultaneous analysis of all phospholipid (PL) classes in negative ion mode has been investigated. While MS analysis of most PL classes is carried out in negative ion mode, analysis of neutral polar (polar but electrically neutral) lipids like phosphatidylcholine (PC) and sphingomyelin (SM) is highly efficient in positive ion mode. Therefore, analysis of PL mixture samples often requires two separate runs in both positive and negative ion mode. In order to establish run conditions to carry out a single nLC-ESI-MS-MS for all PLs, the ionization efficiency of 13 different ...
SICHILONGO, Kwenga F.; MUCKOYA, Vallerie A. y NINDI, Mathew M.. A rapid and sensitive LC-MS/MS method for the determination of multi-class residues of antibiotics in chicken liver. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp.01-06. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a1.. A very sensitive, simple and cost-effective liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method for the determination of multi-class antibiotics in chicken liver was developed. The drugs under consideration were sulfaguanidine and sulfamethazole, trimethoprim, tetracycline, chlortetracycline and tylosin. Linear calibrations were established for all the analytes and the R2 values ranged between 0.9990 and 0.9997. The limits of quantitation (LOQs) varied between 0.025 and 78.8 μg kg-1. The limit of detections (LODs) were better than those that have been reported for the same antibiotics in many instances in other studies and ranged between 0.010-31.5 μg kg-1 with the ...
SICHILONGO, Kwenga F.; MUCKOYA, Vallerie A. e NINDI, Mathew M.. A rapid and sensitive LC-MS/MS method for the determination of multi-class residues of antibiotics in chicken liver. S.Afr.j.chem. (Online) [online]. 2015, vol.68, pp.01-06. ISSN 1996-840X. http://dx.doi.org/10.17159/0379-4350/2015/v68a1.. A very sensitive, simple and cost-effective liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) method for the determination of multi-class antibiotics in chicken liver was developed. The drugs under consideration were sulfaguanidine and sulfamethazole, trimethoprim, tetracycline, chlortetracycline and tylosin. Linear calibrations were established for all the analytes and the R2 values ranged between 0.9990 and 0.9997. The limits of quantitation (LOQs) varied between 0.025 and 78.8 μg kg-1. The limit of detections (LODs) were better than those that have been reported for the same antibiotics in many instances in other studies and ranged between 0.010-31.5 μg kg-1 with the ...
Busulfan is an alkylating agent widely used in the ablation of bone marrow cells before hematopoietic stem cell transplant. Due to large intraindividual and interindividual variations, and narrow therapeutic window, therapeutic drug monitoring of busulfan is warranted. A quick and reliable HPLC-MS/MS method was developed for the assay of plasma busulfan. HPLC involved C18 column, and MS/MS was used in electrospray ionization (ESI) positive mode. Quantitation and identification of busulfan was made using various multiple reactions monitoring (MRMs). Isotopic labeled busulfan-d8 was used as the internal standard. The method is linear from 50 to 2500 ng/mL and has with-in run and between-run imprecision of |10|%.
Sigma-Aldrich offers abstracts and full-text articles by [Gabriela Peste, Nela Bibire, Mihai Apostu, Aurel Vlase, Corneliu Oniscu].
An original liquid chromatography-tandem mass spectrometry (LC-MS-MS) method coupled to online extraction has been developed for cyanide determination in blood. A method involving fluorimetric detection after naphthalene-2,3-dicarboxyaldehyde (NDA) complexation by taurine in the presence of cyanide was previously described. Its performance was limited because of the absence of an internal standard (IS). Using cyanide isotope 13C15N as IS allowed quantification in MS-MS. After the addition of 13C15N, 25 µL of blood were diluted in water and deproteinized with methanol. Following derivatization with NDA and taurine for 10 min at 4°C, 100 µL was injected into the online LC-MS-MS system. An Oasis HLB was used as an extraction column, and a C18 Atlantis was the analytical column. The chromatographic cycle was performed with an ammonium formate (20 mM, pH 2.8) (solvent A) and acetonitrile/solvent A (90:10, v/v) gradient in 6 min. Detection was performed in negative electrospray ionization mode ...
TY - JOUR. T1 - Bioanalysis of 6-diazo-5-oxo-l-norleucine in plasma and brain by ultra-performance liquid chromatography mass spectrometry. AU - Alt, Jesse. AU - Potter, Michelle C.. AU - Rojas, Camilo. AU - Slusher, Barbara. PY - 2015/4/1. Y1 - 2015/4/1. N2 - Glutamine is an abundant amino acid that plays pivotal roles in cell growth, cell metabolism, and neurotransmission. Dysregulation of glutamine-using pathways has been associated with pathological conditions such as cancer and neurodegenerative diseases. 6-Diazo-5-oxo-l-norleucine (DON) is a reactive glutamine analog that inhibits enzymes affecting glutamine metabolism such as glutaminase, 2-N-amidotransferase, l-asparaginase, and several enzymes involved in pyrimidine and purine de novo synthesis. As a result, DON is actively used in preclinical models of cancer and neurodegenerative disease. Moreover, there have been several clinical trials using DON to treat a variety of cancers. Considerations of dose and exposure are especially ...
GE AKTA fast protein liquid chromatography system is an eagle-i resource of type Fast protein liquid chromatography instrument at Universidad Central del Caribe.
Liquid Chromatography / Tandem Mass Spectrometry (LS/MS/MS). Liquid chromatography/tandem mass spectrometry provides identification of analytes of interest within a mixture based on retention time and characteristic parent/daughter ion fragmentation patterns, which provides the compounds unique molecular fingerprint. When liquid chromatography is suitable for separation of compounds, LC/MS/MS can provide significantly greater sensitivity than the corresponding gas chromatography/mass spectrometry (i.e., GC/MS). KorvaLabs employs LC/MS/MS for the identification of substances in "white powders" - such as in the case of certification of dietary supplements - and for certain compounds in urine where GC/MS is not sufficient.. Gas Chromatography / Mass Spectrometry (GC/MS). Like LC/MS, the related gas chromatography/mass spectrometry (i.e., GC/MS)provides identification based on retention time and ion fragmentation patterns; however, GC/MS… KorvaLabs uses GC/MS for the detection of most banned ...
Steuer, Andrea E; Poetzsch, Michael; Stock, Lorena; Eisenbeiss, Lisa; Schmid, Yasmin; Liechti, Matthias E; Kraemer, Thomas (2017). Development and validation of an ultra-fast and sensitive microflow liquid chromatography-tandem mass spectrometry (MFLC-MS/MS) method for quantification of LSD and its metabolites in plasma and application to a controlled LSD administration study in huma. Drug Testing and Analysis, 9(5):788-797. ...
University of Leicester researchers writing in the journal Chemical Research in Toxicology say they have found convincing evidence that cannabis smoke damages DNA and it could potentially increase the risk of cancer development in humans.Using a newly developed highly sensitive liquid chromatography-tandem mass spectrometry method, the University
Disease-specific compounds (biomarkers) are analyzed in clinical laboratories to assist with diagnosing diseases. This thesis describes development and validation of liquid chromatography tandem mass spectrometry (LC-MS/MS) based tests for diagnosing a diverse group of endocrine and metabolic diseases. The analytical methods used on-line and off-line sample extraction and analytical derivatization as means of enhancing the analytical sensitivity, specificity and clinical utility. All developed methods were extensively validated and reference intervals for the biomarker concentrations were established in blood samples of healthy adults and children. Advantages of the LC-MS/MS as an analytical technique include possibility of simultaneous measurement of multiple analytes and ability of confirming their identity. In this thesis we proposed and evaluated approaches for the assessment of the specificity of analysis in the methods that use tandem mass spectrometry detection. To enhance throughput of ...
Abstract To support therapeutic drug monitoring of patients with cancer, a fast and accurate method for simultaneous quantification of the registered anticancer drugs afatinib, axitinib, ceritinib, crizotinib, dabrafenib, enzalutamide, regorafenib and trametinib in human plasma using liquid chromatography tandem mass spectrometry was developed and...
In this study, the anti-melanogenesis efficacy of clinically used herbal prescription LASAP-C, which consists of four herbal medicines-Rehmanniae Radix Crudus, Lycii Fructus, Scutellariae Radix, and Angelicae Dahuricae Radix, was investigated. The chemical profile of LASAP-C was established by conducting ultra-performance liquid chromatography-electrospray ionization-mass spectrometry. Anti-melanogenic efficacy was evaluated by tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 expression in B16F10 melanoma cells. In vivo evaluation was performed by using zebrafish model. Molecular evidences suggested that melanin synthesis was inhibited via the down-regulation of tyrosinase, tyrosinase-related protein (TRP)-1, and TRP-2 expression in B16F10 melanoma cells treated with LASAP-C. The anti-melanogenesis efficacy was also confirmed in vivo by using the zebrafish model. The results of this study provide strong evidences that LASAP-C can be used as an active component in cosmeceutical products for
In this study, we developed the stable isotope dilution hydrophilic interaction liquid chromatography with tandem mass spectrometry (HILIC-MS/MS) technique for the accurate, reasonable and simultaneous quantification of glutamic acid (Glu), glutamine (Gln), pyroglutamic acid (pGlu), γ-aminobutyric acid (GABA) and theanine in mouse brain tissues. The quantification of these analytes was accomplished using stable isotope internal standards and the HILIC separating mode to fully correct the intramolecular cyclization during the electrospray ionization. It was shown that linear calibrations were available with high coefficients of correlation (r(2) | 0.999, range from 10 pmol/mL to 50 mol/mL). For application of the theanine intake, the determination of Glu, Gln, pGlu, GABA and theanine in the hippocampus and central cortex tissues was performed based on our developed method. In the region of the hippocampus, the concentration levels of Glu and pGlu were significantly reduced during reality-based theanine
A polyacrylamide (PAAm)-modified monolithic silica capillary column of increased phase ratio, 200T-PAAm, for hydrophilic interaction liquid chromatography (HILIC) was prepared. The column showed high separation efficiency, with a theoretical plate height H = 7â€"20 μm at a linear velocity, u = 1â€"7 mm/s. From a kinetic plot analysis, it was expected that the monolithic column could provide three times faster separation than particle-packed HILIC columns under a pressure limit at 20 MPa. HILIC coupled with electrospray ionization (ESI)â€"mass spectrometry (HILIC-ESI-MS) using the 200T-PAAm column was employed for the analysis of underivatized carbohydrates to achieve fast and efficient separations of mixtures containing mono-, di-, and trisaccharides within 5 min. Under single MS full scan mode, 200 pg of oligosaccharides was detected by the system. The limit of detection (LOD) of the LC-ESI-MS/MS system was determined using selected reaction monitoring (SRM) to be as low as 3.2 ...
1,2-Dehydro-N-acetyldopamine (dehydro NADA) and its derivatives have been identified as important cuticular sclerotizing precursors responsible for the hardening of the exoskeleton of soft-bodied insects. In addition, these compounds may serve as precursors in the biosynthesis of the large number of bioactive compounds present in the exoskeleton of marine invertebrates. In this work the products of non-enzymatic oxidation of 1,2-dehydro N-acyldopamine were examined using reversed-phase high performance liquid chromatography/electrospray/tandem mass spectrometry (RP-HPLC/ESI/MS-MS). In addition, the role of tyrosinase-catalyzed oxidation of dehydro-N-acetyldopamine in the cross-linking of cuticle proteins was studied by examining two thiol-containing nucleophiles and a model peptide using RP- HPLC/ESI/MS-MS. Finally, the tyrosinase-catalyzed oxidative cyclization and polymerization of N-acetyl-1,2-dehydro Dopa was examined as a possible biosynthetic pathway for forming bioactive compounds called
ePIC (electronic Publication Information Center) is the official repository for publications and presentations of Alfred Wegener Institute for Polar and Marine Research (AWI)
Learn about Agilent׷ liquid chromatography/mass spectrometry (LC/MS). Agilent LC/MS enables a wide array of applications by combining sample preparation, liquid chromatography (LC), mass spectrometry (MS), and dedicated software tools like compound databases and libraries.
Journal of Chemistry is a peer-reviewed, Open Access journal that publishes original research articles as well as review articles on all aspects of fundamental and applied chemistry.
Manufacturer of Liquid Chromatography Mass Spectrometry - LCMS QQQ 6460 Mass Spectrometer, CAH Mass Solution offered by Trivitron Healthcare Pvt. Ltd., Chennai, Tamil Nadu.
Many direct immunoassays in use today for testosterone analysis are little better than a guess at the low levels that are sometimes required.  This has led many clinical societies to adv
Lai, Yongquan, "Development and application of liquid chromatography mass spectrometry methods for the analysis and toxicity study of polybrominated diphenyl ether metabolites" (2013). Restricted Access Theses and Dissertations. 1437 ...
This contribution relates to the assessment of gradient-elution parameters in capillary liquid chromatography affecting the peak widths in the reversed-phase separation of peptides and intact proteins. Gradient separations were performed using both a poly(sytrene-co-divinylbenzene) monolithic column and a microparticulate fused-core column (silica C18, 2.7 mu m). The applicability of the conventional linear (LSS) and non-linear solvent-strength model (Neue-Kuss) were investigated to describe the retention behaviour of the compounds as a function of the mobile-phase composition. This was performed by using a wide range of gradient conditions, including different gradient slopes (beta, ranging from 0.05 to 0.65 min(-1)) and mobile-phase compositions (Delta phi, i.e. gradient span). Although the LSS-model provided accurate retention time predictions (,1.3% deviation) of scouting runs with more conventional gradient slopes, the prediction of high-speed separations with a high degree of accuracy ...
Results .Quantifying multi-omics data under circadian cycles . To investigate global phosphorylation in flies, we conducted quantitative proteomics and phosphoproteomics using the Tandem Mass Tag (TMT) labeling and liquid chromatography-tandem mass spectrometry (LC-MS/MS) on WT and per 0fly heads collected at 3?h intervals on 2 days under constant darkness (DD) condition (Fig.? 1a ). Altogether we identified 61,460 non-phosphorylated peptides and 12,465 phosphopeptides from 32 samples. The majority of the peptides (35,280; 57.40%) and phosphopeptides (8193; 65.73%) could be matched with ≥2 spectral counts, whereas the average spectral counts were 2.5 and 4.4 for all peptides and phosphopeptides, respectively (Fig.? 1b ). We next mapped non-phosphorylated peptides to their corresponding protein sequences, and obtained 5998 and 6034 proteins in WT and per 0flies, respectively (Supplementary Data? 1 ). Only 14.87% (912) of 6134 quantified proteins were assigned with one matched peptide, with an ...
J Chromatogr B Analyt Technol Biomed Life Sci. 2007 Sep 15;857(1):1-8. Epub 2007 Jun 29. Comparative Study; Evaluation Studies; Research Support, N.I.H., Extramural
Plant polysaccharides constitute arguably the most complex family of biomacromolecules in terms of the stereochemistry and regiochemistry of their intramolecular linkages. The chemical modification of such polysaccharides introduces an additional level of complexity for structural determinations. We have developed an integrated analytical procedure combining selective enzymatic hydrolysis, hydrophilic interaction liquid chromatography (HILIC), and mass spectrometry (MS) to describe the substitution pattern of xyloglucan (XyG) and its chemo-enzymatic derivatives (cationic, anionic, and benzyl aminated). Enzymatic hydrolysis of XyG derivatives by a xyloglucan-specific endoglucanase (XEG) generates oligosaccharides amenable for mass spectrometric identification with distinct structures, based on enzymatic substrate recognition and hydrolytic pattern. Matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-ToF-MS) and electrospray ionisation mass spectrometry (ESI-MS) ...
The recent explosion in available genomic and protein sequence information is providing a sequence infrastructure for the emerging field of proteomics. A major aspect of many proteomics strategies is the identification of proteins using an analytical "fingerprint" that can be used to search a sequence database. One common "fingerprint" is the tandem mass (MS/MS) spectrum of a peptide. Thus, an MS/MS spectrum can be algorithmically compared with predicted peptide spectra from a sequence database to identify the respective protein (1, 2). The digestion of intact protein mixtures followed by the direct analysis of the resulting peptides by capillary liquid chromatography-MS/MS has facilitated "shotgun" identification of protein mixtures without the need for prior sample fractionation (3). Combined with the recent development of capillary multidimensional liquid chromatography [multidimensional protein identification technology (MudPIT)], this approach is now capable of characterizing proteins ...
Trypanosomatids express complex glycoproteins and glycolipids that are often essential to their viability and virulence. In these parasites, sugar nucleotides are the sugar donors for protein and lipid glycosylation. But there had been no information on which sugar nucleotides are present in these parasites, and what their cellular concentrations might be. Daniel C. Turnock and Michael A.J. Ferguson of the University of Dundee, Scotland, United Kingdom, developed a new liquid chromatography/tandem mass spectrometry method to sensitively and selectively identify and measure sugar nucleotides in cell extracts.
Data Advisory. The purpose of this analytical note is to inform researchers that serum 25-hydroxyvitamin D (25(OH)D) data from NHANES III (1988-1994) and NHANES 2001-2006 have been converted by using regression to equivalent 25(OH)D measurements from a standardized liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The LC-MS/MS method was used in the analysis of the newly released NHANES 2007-2010 25(OH)D data. This standardization was done so that researchers could use 25(OH)D data that are equivalent to 25(OH)D measurements assayed with a LC-MS/MS method that is traceable to the NIST reference materials. The LC-MS/MS-equivalent data for NHANES III (1988-1994) and NHANES 2001-2006 are needed to compare with 25(OH)D data from NHANES 2007-2010, which were obtained using the LC-MS/MS method. This analytical note replaces the previous analytical note entitled "Revised Analytical Note for NHANES 2000-2006 and NHANES III (1988-1994) 25-Hydroxyvitamin D Analysis (Revised November ...
Hydrophilic interaction liquid chromatography (HILIC), although not a new technique, has enjoyed a recent renaissance with the introduction of robust and reproducible stationary phases. It is consequently finding application in metabolomics studies, which have traditionally relied on the stability of reversed phases (RPs), since the biofluids analyzed are predominantly aqueous and thus contain many polar analytes. HILICs retention of those polar compounds and use of solvents readily compatible with mass spectrometry have seen its increasing adoption in studies of complex aqueous metabolomes. This review describes the stationary phases and their features. surveys HILIC-LC-MSs role in metabolomics experiments, discusses approaches to data extraction and analysis including multivariate analysis, and reviews the literature on HILIC MS applications in metabolomics. (C) 2009 Wiley Periodicals, Inc., Mass Spec Rev 29:671-684, 2010 ...
In the article below, Jie Ding, associate director of development and validation at the PPD® Laboratories GMP lab, discusses liquid chromatography-mass spectrometry in drug discovery and development.. In a drug stability program, high-performance liquid chromatography (HPLC) with ultraviolet (UV) detection remains the most common and cost-effective methodology. Even so, UV detection has its own limitations, including poor sensitivity for non-UV absorbing compounds and lack of specificity. These shortcomings in turn have motivated scientists to pursue other alternatives. Mass spectrometry detection is such a candidate. Mass spectrometry (MS) is a detection method that measures the mass-to-charge ratio (m/z) of a compound. Compared to UV detection, MS offers higher sensitivity, better detection limits, and the ability to provide additional molecular weight information-making it an "information rich" detection method.. Over the last two decades, MS has become an important analytical tool to ...
Development and validation of a hydrophilic interaction chromatography-tandem mass spectrometry for quantification of nicotine and its metabolites in human maternal and cord ...
Definition : High-pressure packed-column liquid chromatography systems in which the packing of the column is made of microparticulate silica gel. The functional groups of the stationary phase may be polar relative to those of the mobile phase (i.e., normal bonded-phase chromatography) or, more usually, nonpolar (i.e., reverse bonded-phase chromatography).. Entry Terms : "Reverse-Phase Liquid Chromatography Systems" , "Normal-Phase Liquid Chromatography Systems" , "Bonded-Phase Liquid Chromatography Systems". UMDC code : 18278 ...
Paul A. Rudnick, Karl R. Clauser, Lisa E. Kilpatrick, Dmitrii V. Tchekhovskoi, Pedatsur Neta, Nikša Blonder, Dean D. Billheimer, Ronald K. Blackman, David M. Bunk, Helene L. Cardasis, Amy-Joan L. Ham, Jacob D. Jaffe, Christopher R. Kinsinger, Mehdi Mesri, Thomas A. Neubert, Birgit Schilling, David L. Tabb, Tony J. Tegeler, Lorenzo Vega-Montoto, Asokan Mulayath Variyath, Mu Wang, Pei Wang, Jeffrey R. Whiteaker, Lisa J. Zimmerman, Steven A. Carr, Susan J. Fisher, Bradford W. Gibson, Amanda G. Paulovich, Fred E. Regnier, Henry Rodriguez, Cliff Spiegelman, Paul Tempst, Daniel C. Liebler and Stephen E. Stein ...
Sathananthan M, Sathananthan A, Scheithauer BW, Giannini C, Meyer FB, Atkinson JL, Erickson D. Sellar meningiomas: an endocrinologic perspective. Pituitary. 2012 May 27.. Smushkin G, Sathananthan M, Sathananthan A, Dalla Man C, Micheletto F, Zinsmeister AR, Cobelli C, Vella A. Diabetes-associated common genetic variation and its association with GLP-1 concentrations and response to exogenous GLP-1. Diabetes. 2012 May;61(5):1082-9. Smushkin G, Sathananthan A, Man CD, Zinsmeister AR, Camilleri M, Cobelli C, Rizza RA, Vella A. Defects in GLP-1 response to an oral challenge do not play a significant role in the pathogenesis of prediabetes. J Clin Endocrinol Metab. 2012 Feb;97(2):589-98.. Erickson D, Singh RJ, Sathananthan A, Vella A, Bryant SC. Late-night salivary cortisol for diagnosis of Cushings syndrome by liquid chromatography/tandem mass spectrometry assay. Clin Endocrinol (Oxf). 2012 Apr;76(4):467-72.. Sathananthan A, Dalla Man C, Zinsmeister AR, Camilleri M, Rodeheffer RJ, Toffolo G, ...
Analysis of compounds present in complex matrices is always a challenge, which can be partly overcome by applying various sample preparation techniques prior to detection. Ideally, the extraction techniques should be as selective as possible, to minimize the concentration of interfering substances. In addition, results can be improved by efficient chromatographic separation of the sample components. The elimination of interfering substances is especially important when utilizing mass spectrometry (MS) as a detection technique since they influence the ionization yields. It is also important to optimize ionization methods in order to minimize detection limits.. In the work this thesis is based upon, selective solid phase extraction (SPE) materials, a restricted access material (RAM) and graphitized carbon black (GCB) were employed for clean up and/or pre-concentration of analytes in plasma, urine and agricultural drainage water prior to liquid chromatography/mass spectrometry (LC/MS). Two SPE ...