• laboratory
  • Dr. Julia Laskin and Dr. Alexander Laskin at Pacific Northwest National Laboratory and Dr. Sergey Nizkorodov at University of California, Irvine wrote a comprehensive review of new mass spectrometry techniques suitable to studying these complex systems. (pnnl.gov)
  • Julia and Alex Laskin acknowledge the Chemical Imaging Initiative funded through Pacific Northwest National Laboratory's Laboratory Directed Research and Development program which allowed compilation of this review. (pnnl.gov)
  • lethal venoms are often characterised by the median lethal dose (LD50, LD50, or LD-50), expressed in terms of mass fraction (e.g., milligrams of toxin per kilogram of body mass), that will kill 50% of the target of a specified type (e.g., laboratory mice). (wikipedia.org)
  • Through the 1980s three dedicated journals appeared in the field: Journal of Chemometrics, Chemometrics and Intelligent Laboratory Systems, and Journal of Chemical Information and Modeling. (wikipedia.org)
  • MALDI-TOF
  • The most widely used instrument for peptide mass analysis are the MALDI-TOF instruments as they permit the acquisition of peptide mass fingerprints (PMFs) at high pace (1 PMF can be analyzed in approx. (wikipedia.org)
  • electrospray ionization
  • Nowadays, most extensively applied LC-MS interfaces are based on atmospheric pressure ionization (API) strategies like electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photo-ionization (APPI).These interfaces became available in the 1990s after a two decade long research and development process. (wikipedia.org)
  • One of the techniques -- Nanospray Desorption Electrospray Ionization, or nano-DESI, Mass Spectrometry, developed at PNNL -- enables sensitive analysis of hundreds of organic molecules in aerosol samples. (pnnl.gov)
  • Fragmentation
  • For example, even PTR-MS, another soft ionisation technology that uses the H3O+ reagent ion, has been shown to give considerably more product ion fragmentation than SIFT-MS. Another key feature of SIFT-MS is the upstream mass quadrupole, which allows the use of multiple precursor ions. (wikipedia.org)
  • molecules
  • Asphaltenes do not have a specific chemical formula: individual molecules can vary in the number of atoms contained in the structure, and the average chemical formula can depend on the source. (wikipedia.org)
  • Yet, these identifications, especially for isomeric molecules, are crucial for establishing chemical mechanisms that inform climate models. (tofwerk.com)
  • Seventy years later, T. reesei is a star in the world of biofuels because of its ability to churn out enzymes that chew through molecules like complex sugars. (innovations-report.com)
  • Analyzing complex, heterogeneous systems, such as atmospheric aerosols, and understanding their impact requires tools that can accurately identify and quantify hundreds of molecules,' said Julia Laskin. (pnnl.gov)
  • Concurrently, the neutral analyte molecules of a sample vapor enter the flow tube, via a heated sampling tube, where they meet the precursor ions and may undergo chemical ionization, depending on their chemical properties, such as their proton affinity or ionization energy. (wikipedia.org)
  • In hydrocarbons and in the vapor phase, it consists of hydrogen-bonded dimers rather than individual molecules. (wikipedia.org)
  • Stacking, a chemical property of molecules with aromaticity, is seen occurring between phenolic molecules. (wikipedia.org)
  • Aromatic molecules consequently do not easily break apart and react with other substances (they have low chemical reactivity) and exhibit special physical characteristics such as π stacking (the understanding of which is still the subject of ongoing investigation). (wikipedia.org)
  • The discipline involves the application of chemical techniques, analysis, and often small molecules produced through synthetic chemistry, to the study and manipulation of biological systems. (wikipedia.org)
  • In contrast to research using biochemistry, genetics, or molecular biology, where mutagenesis can provide a new version of the organism, cell, or biomolecule of interest, chemical biology probes systems in vitro and in vivo with small molecules that have been designed for a specific purpose or identified on the basis of biochemical or cell-based screening (see chemical genetics). (wikipedia.org)
  • Typical 13C NMR chemical shifts of carbohydrate ring carbons are 60-110 ppm In the case of simple mono- and oligosaccharide molecules, all proton signals are typically separated from one another (usually at 500 MHz or better NMR instruments) and can be assigned using 1D NMR spectrum only. (wikipedia.org)
  • liquid
  • Until his discovery, liquid perfumes consisted of mixtures of oil and crushed herbs or petals, which made a strong blend. (wikipedia.org)
  • Dr. Zhentian Lei , assistant director and assistant research professor of the MU Metabolomics Center, provides an overview of an ultra high-pressure liquid chromatograph coupled to mass spectrometry for the large-scale profiling of metabolites at the University of Missouri Metabolomics Center open house on Aug. 12. (missouri.edu)
  • They also discussed techniques for surface analysis of individual particles and surface chemistry of liquid drops. (pnnl.gov)
  • When methanol and carbon monoxide are combined in the presence of a strong base, the result is methyl formate, according to the chemical equation: CH3OH + CO → HCO2CH3 In industry, this reaction is performed in the liquid phase at elevated pressure. (wikipedia.org)
  • spectra
  • Due to the different chemical properties of the aforementioned precursor ions (H3O+, NO+, and O2+), different FS mode spectra can be produced for a vapor sample, and these can give different information relating to the composition of the sample. (wikipedia.org)
  • SIFT-MS utilises an extremely soft ionisation process which greatly simplifies the resulting spectra and thereby facilitates the analysis of complex mixtures of gases, such as human breath. (wikipedia.org)
  • The objective is to develop models which can be used to predict properties of interest based on measured properties of the chemical system, such as pressure, flow, temperature, infrared, Raman, NMR spectra and mass spectra. (wikipedia.org)
  • lipids
  • These protocols work relatively well for a wide variety of physiologically relevant lipids but they have to be adapted for complex lipid chemistries and low-abundance and labile lipid metabolites. (wikipedia.org)
  • structural
  • Among structural properties that could be determined by NMR are primary structure (including stereochemistry), saccharide conformation, stoichiometry of substituents, and ratio of individual saccharides in a mixture. (wikipedia.org)
  • Substitution positions in residues Sequence of residues Stoichiometry of terminal residues and side chains Location of phosphate and sulfate diester bonds Polymerization degree and frame positioning (for polysaccharides) Wide known methods of structural investigation, such as mass-spectrometry and X-ray analysis are only limitedly applicable to carbohydrates. (wikipedia.org)
  • separation
  • It is also possible to obtain separation of a few parts per million of a contaminant from a mixture of much more concentrated materials. (encyclopedia.com)
  • In GC, the analytes are eluted from the separation column as a gas and the connection with electron ionization (EI) or chemical ionization (CI) ion sources in the MS system was a technically simpler challenge. (wikipedia.org)
  • Rapid (ms) separation of ions based on shape, mass and charge. (gre.ac.uk)
  • In the case of an optimal separation, different peaks or patterns on the chromatogram correspond to different components of the separated mixture. (wikipedia.org)
  • extraction
  • Second, the technique may have seemed too simple to chemists who were used to relying on lengthy extraction, crystallization, or distillation processes to separate mixtures. (discoveriesinmedicine.com)
  • When organic soil was used, citrate buffer in the extraction mixture gave higher amounts of lipid phosphate than acetate buffer, Tris, H2O or phosphate buffer. (wikipedia.org)
  • synthesis
  • In 1828 Friedrich Wöhler produced the organic chemical urea (carbamide), a constituent of urine, from inorganic starting materials (the salts potassium cyanate and ammonium sulfate), in what is now called the Wöhler synthesis. (wikipedia.org)
  • It is an important intermediate in chemical synthesis and occurs naturally, most notably in some ants. (wikipedia.org)
  • Oligonucleotide synthesis is the chemical synthesis of relatively short fragments of nucleic acids with defined chemical structure (sequence). (wikipedia.org)
  • Whereas enzymes synthesize DNA and RNA only in a 5' to 3' direction, chemical oligonucleotide synthesis does not have this limitation, although it is, most often, carried out in the opposite, 3' to 5' direction. (wikipedia.org)
  • crude
  • Asphaltenes impart high viscosity to crude oils, negatively impacting production, also the variable asphaltene concentration in crude oils within individual reservoirs creates a myriad of production problems. (wikipedia.org)
  • Rapidly
  • Rapidly, it was realized that the analysis of complex mixtures would require the development of a fully automated on-line coupling solution in LC-MS. The moving-belt interface (MBI) was developed in 1977. (wikipedia.org)
  • The instrument can be programmed either to scan across a range of masses to produce a mass spectrum (Full Scan, FS, mode), or to rapidly switch between only the m/z values of interest (Multiple Ion Monitoring, MIM, mode). (wikipedia.org)
  • trap
  • There are a lot of mass analyzers that can be used in LC/MS. Single Quadrupole , Triple Quadrupole , Ion Trap , TOF ( time of Flight ) and Quadrupole-time of flight (Q-TOF). (wikibooks.org)
  • identification
  • An integrated approach utilizing artificial neural networks and SELDI mass spectrometry for the classification of human tumours and rapid identification of potential biomarkers", Bioinformatics, 2002, vol. 18, pp. 395-404. (patentgenius.com)
  • In descriptive applications, properties of chemical systems are modeled with the intent of learning the underlying relationships and structure of the system (i.e., model understanding and identification). (wikipedia.org)
  • chemistry
  • Based on our results, we anticipate that many aspects of bacterial chemistry including chemical structures, pharmacological potential, and ecological significance are yet to be uncovered,' adds Bandow. (news-medical.net)
  • Boosted Decision Tree Analysis of Surface-enhanced Laser Desorption/Ionization Mass Spectral Serum Profiles Discriminates Prostate Cancer from Noncancer Patients", Clinical Chemistry, 2002, vol. 48, pp. 1835-1843. (patentgenius.com)
  • A crucial breakthrough for organic chemistry was the concept of chemical structure, developed independently in 1858 by both Friedrich August Kekulé and Archibald Scott Couper. (wikipedia.org)
  • Chemical biology is a scientific discipline spanning the fields of chemistry and biology. (wikipedia.org)
  • In contrast to biochemistry, which involves to study of the chemistry of biomolecules and regulation of biochemical pathways within and between cells, chemical biology deals with chemistry applied to biology. (wikipedia.org)
  • Chemometrics is inherently interdisciplinary, using methods frequently employed in core data-analytic disciplines such as multivariate statistics, applied mathematics, and computer science, in order to address problems in chemistry, biochemistry, medicine, biology and chemical engineering. (wikipedia.org)
  • 1980s
  • Many early applications involved multivariate classification, numerous quantitative predictive applications followed, and by the late 1970s and early 1980s a wide variety of data- and computer-driven chemical analyses were occurring. (wikipedia.org)
  • substrates
  • Here, chemical biologists can develop reagents to interact with substrates, specifically and tightly, to profile a targeted functional group on a proteome scale. (wikipedia.org)
  • techniques
  • Conservation scientists conduct applied scientific research and techniques to determine the material, chemical, and technical aspects of cultural heritage. (wikipedia.org)
  • The team wrote an invited review article on new mass spectrometry techniques for atmospheric science. (pnnl.gov)
  • Carbon-13 NMR overcomes this disadvantage by larger range of chemical shifts and special techniques allowing to block carbon-proton spin coupling, thus making all carbon signals high and narrow singlets distinguishable from each other. (wikipedia.org)
  • different
  • To isolate different types of chlorophyll, he trickled a mixture of dissolved pigments through a glass tube packed with calcium carbonate powder. (discoveriesinmedicine.com)
  • To assess the effectiveness of mixtures of these enzymes, scientists must either measure the overall performance of the mixture, or they must test the component enzymes one at a time to see how each reacts to different conditions like temperature, pressure and pH. (innovations-report.com)
  • The history of environmental chemical pollutants is dominated by several chemical compound classes of different characteristics such as petroleum hydro-carbons, polycyclic aromatic hydrocarbons, synthetic surfactants, polychlorinated insecticides, polychlorinated biphenyls, polychlorinated dibenzodioxins, arsenic, heavy metals, tin organics, etc. (royalsocietypublishing.org)
  • Looking at the characteristics of an individual down through these different levels of detail, there is an increasingly more accurate prediction of a person's ability to respond to a pharmaceutical compound. (wikipedia.org)
  • The various constituents of the mixture travel at different speeds, causing them to separate. (wikipedia.org)
  • reactivity
  • Study of properties includes both physical properties and chemical properties, and uses similar methods as well as methods to evaluate chemical reactivity, with the aim to understand the behavior of the organic matter in its pure form (when possible), but also in solutions, mixtures, and fabricated forms. (wikipedia.org)
  • high
  • These two types of instrument are preferable here because of their wide mass range, and in the case of FT-ICR, its high mass accuracy. (wikipedia.org)
  • closely
  • Overall, the goal of pharmacometabolomics is to more closely predict or assess the response of an individual to a pharmaceutical compound, permitting continued treatment with the right drug or dosage depending on the variations in their metabolism and ability to respond to treatment. (wikipedia.org)
  • researchers
  • Both researchers suggested that tetravalent carbon atoms could link to each other to form a carbon lattice, and that the detailed patterns of atomic bonding could be discerned by skillful interpretations of appropriate chemical reactions. (wikipedia.org)