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ADME/Pharmacokinetic Studies from Serum and Plasma: Improvements in Sample Preparation and LC–MS Analysis of Therapeutic OligonucleotidesThe authors discuss improvements in sample preparation for ADME/pharmacokinetic studies of therapeutic oligonucleotides.
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High-Definition Screening for Boar Taint in Fatback Samples Using GC–MSHigh-definition screening by gas chromatography–mass spectrometry (GC–MS) is shown to be a viable option for the reliable identification of odorous compounds in pork.
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Metabolite Profiling Applications in Early Drug DiscoveryMetabolite profiling in drug discovery can contribute significantly at the lead optimization stage in two main application areas. The first is the identification of major metabolites, which provides medicinal chemists with information on the metabolic "soft spots." These soft spots are locations on the molecule particularly susceptible to metabolic modification, which can contribute to high pharmacokinetic clearance. This information then can be used to optimize the structure of a lead compound or chemical series to slow the rate of metabolism and therefore reduce hepatic clearance. This improves the absorption, distribution, metabolism, and excretion (ADME) properties of the compound, such as bioavailability, exposure (as measured by area under the curve), and half-life. Through iterative optimization of the structure and timely generation of metabolism data following each structural modification, pharmacokinetic properties can be improved while maintaining activity against the therapeutic target.
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The Chemical Analysis ProcessThe authors present an overview of the chemical analysis process.
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High-Throughput Trace Analysis Using SERS-Coated Microtiter Plates with a Raman Plate ReaderSurface-enhanced Raman spectroscopy (SERS) has been studied extensively over the last few decades with many advances in preparation of SERS substrates and coatings. While the bulk of the research in SERS substrate preparation has been devoted to pushing detection limits to higher sensitivity for measurement of single samples, the application of SERS to high-throughput analysis has been largely ignored. In this article, we present the use of commercially available SERS-coated microtiter plates in a dedicated Raman microtiter plate reader, enabling high-throughput trace analysis measurements. This article also describes the SERS substrate, the high-throughput plate reader, and preliminary results from samples representing trace analysis of explosives, nerve agents, pharmaceuticals, and biological compounds.
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Radio Frequency Glow Discharge Optical Emission Spectroscopy: Depth Profiling Analysis of Thin Anodic Alumina Films as Potential Reference Materials (PDF)The need for reference materials that can be applied in the area of thin films analysis has long been realized but is still, in general, under-addressed. Alumina films of single-micrometer thickness, having either fine distributions of impurities or delta function impurity marker layers, can be prepared routinely by anodic oxidation of electropolished aluminum specimens in appropriate electrolytes. Selected films were examined by transmission electron microscopy (TEM) and analyzed by radio frequency glow discharge optical emission spectroscopy (rf-GD-OES), providing very rapid, yet high-resolution, depth-resolved analysis of these electrically insulating materials.
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Carbon Nanotube Characterization by Resonance Raman SpectroscopyPhoton etc. has designed two narrowband tunable filters for resonance Raman spectroscopy.
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Moving Mid-IR Spectroscopy Forward in MedicineNick Stone of the University of Exeter explains why mid-infrared (mid-IR) spectroscopy is so valuable for spectral imaging in disease research and clinical diagnostics, and discusses his own recent work in this area.
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Fluorescence Spectroscopy: Theory and System DesignThis application note explores the fundamentals of fluorescence and different types of measurement setups.
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Improving the Analytical Workflow for Protein Biopharmaceutical Characterization with a Novel LC–MS System SolutionThis article presents an efficient analytical workflow for protein characterization using LC–MS.
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Low-Resolution Raman Spectroscopy in Science EducationRecent developments in photonics are finally making Raman instrumentation accessible to larger basic laboratories.
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Online Identification of Flavones from Flos Chrysanthemi by LC–MS-IT-TOFThe use of medicinal herbs as alternative treatment methods continues to grow. With this escalating use has come an increasing interest in determining the chemical compositions of these herbs in order to obtain a better understanding of their makeup and effects. In this study, Flos Chrysanthemi, a commonly used traditional Chinese medicine that has been cultivated for centuries, was analyzed to identify the main flavone compositions in one original breed of Flos Chrysanthemi (Hangbaiju) in China.
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Confocal Raman AFM Imaging of PaperA better understanding of the micro- and nanostructures of cellulose fiber composition before and after various chemical treatments, together with the distribution of bleaching additives to the final paper composition, is essential for further improvements of paper properties. Confocal Raman imaging is a valuable tool for such studies, as it reveals not only optical information but also information regarding the 3D distribution of the chemical compounds in the submicrometer range. In the paper surface finishing process, additional surface roughness parameters can be measured by combining confocal Raman microscopy with atomic force microscopy. Such combined analytical microscopes allow a direct linking between high-resolution imaging and chemical identification of various species on a surface.
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Comparison of Extracts from Dry and Alcohol-Steamed Root of Polygonatum kingianum (Huang Jing) by Sub-2-µm–LC–TOF-MSMost plants used in traditional Chinese medicine must be processed before their medicinal usage; hence the effective ingredients may differ from those in the freshly harvested plant extracts. In this work, we present a fast and generic approach using sub-2-?m liquid chromatography–time-of-flight–mass spectrometry (sub-2-?m-LC–TOF-MS) coupled with multivariate statistical data analysis to systematically profile ingredient changes between fresh and processed samples of huang jing.
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ADME/Pharmacokinetic Studies from Serum and Plasma: Improvements in Sample Preparation and LC–MS Analysis of Therapeutic OligonucleotidesThe authors discuss improvements in sample preparation for ADME/pharmacokinetic studies of therapeutic oligonucleotides.
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Dried Blood Spots and High-Resolution Mass Spectrometry for Discovery Fast PK BioanalysisThis article introduces the advantages of accurate mass high-resolution mass spectrometry LC–MS (HRMS) coupled to the dried blood spot (DBS) technique for fast PK applications in a discovery environment. Compared with the established norm of plasma bioanalysis using triple quadrupoles, HRMS coupled to DBS is a viable alternative. The benefit is access to critical new information (HRMS bioanalysis) and significantly less stress on the animal (DBS), both factors that potentially improve the quality of early PK data.
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Improving the Analytical Workflow for Protein Biopharmaceutical Characterization with a Novel LC–MS System SolutionThis article presents an efficient analytical workflow for protein characterization using LC–MS.
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Carbon Nanotube Characterization by Resonance Raman SpectroscopyPhoton etc. has designed two narrowband tunable filters for resonance Raman spectroscopy.
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A Dedicated Spectra Database for Multiline Selection in ICP-AESAcquisition and interpretation of a spectra database for ICP-AES analysis are described. The aim is the selection of nanometer-wide spectral windows containing several elements and several lines per element, so as to perform multiline analysis. An automatic line assignment procedure has been used. Information such as wavelength, sensitivity, line width, limit of detection, and level of detector saturation are stored. Filtering procedures are used for line selection, taking into account concentrations and possible spectral interferences.
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Qualitative and Quantitative Metabolite Identification for Verapamil in Rat Plasma by Sub-2-μm LC Coupled with Quadrupole TOF-MSAn effective metabolite identification study should ideally include both qualitative and quantitative information that for both identifying metabolites, and determining the rate of clearance and the metabolic routes of the parent drug. Liquid chromatography–mass spectrometry (LC–MS) is considered the standard analytical technique for metabolite identification studies. To date, however, qualitative and quantitative information has always been obtained from two separation platforms: quadrupole time-of-flight (QTof) MS for the exact mass full-scan qualitative study, and tandem quadrupole MS for the multiple reaction monitoring (MRM) quantitative study. With advancements to QTof instrumentation, specifically, recent improvements in sensitivity and dynamic range, it is now possible to perform both qualitative and quantitative experiments on a single QTof mass spectrometer. This article describes a workflow that allows simultaneous qualitative and quantitative metabolite identification studies to be..
Latest:
Qualitative and Quantitative Metabolite Identification for Verapamil in Rat Plasma by Sub-2-μm LC Coupled with Quadrupole TOF-MSAn effective metabolite identification study should ideally include both qualitative and quantitative information that for both identifying metabolites, and determining the rate of clearance and the metabolic routes of the parent drug. Liquid chromatography–mass spectrometry (LC–MS) is considered the standard analytical technique for metabolite identification studies. To date, however, qualitative and quantitative information has always been obtained from two separation platforms: quadrupole time-of-flight (QTof) MS for the exact mass full-scan qualitative study, and tandem quadrupole MS for the multiple reaction monitoring (MRM) quantitative study. With advancements to QTof instrumentation, specifically, recent improvements in sensitivity and dynamic range, it is now possible to perform both qualitative and quantitative experiments on a single QTof mass spectrometer. This article describes a workflow that allows simultaneous qualitative and quantitative metabolite identification studies to be..
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Spectroscopy: A Technology for All SeasonsSpectroscopy techniques are an important facet of the laboratory analytical and life science instrument industry, which continues to expand as its analytical requirements migrate across industries and geographic regions. Overall industry growth has been in the 6-8% range for the last few years, which is a sign of both its maturity and its stability. The demands of the life science marketplace, environmental concerns, and the search for new materials are important driving forces. Likewise, the shifting market focus from North America and Europe to Asia is changing the face of the industry. It is expected that 2008 will be a good year for the industry despite the likely economic slowdown in North America and Europe.
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Comparing Single Quadrupole with Triple Quadrupole GC–MS-Based MetabolomicsBruker Daltonics, Inc.
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Using LC–oa-TOF MSE with a Multivariate Statistical Sample Statistical Sample Profiling Strategy to Distinguish Chinese Red Ginseng from Korean Red GinsengBoth Chinese ginseng and Korean ginseng are similar plant species and undergo similar handling procedures when harvested and processed for sale. Despite their similarities, Korean ginseng commands a higher price than Chinese ginseng on the open market and is believed to produce different clinical effects than Chinese ginseng. Chinese researchers are now employing new techniques on the two varieties of ginseng to understand their chemical differences. HPLC/UV-based strategies for distinguishing the two types of ginseng have proven to be mostly ineffective due to lack of resolution. Using UltraPerformance liquid chromatography/orthogonal acceleration (oa)–TOF mass spectrometry and exact mass measurement, the authors developed a high-resolution method using multivariate statistical analysis for separating and identifying differences between Chinese ginseng and Korean ginseng at the molecular level.
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An Investigation into the Use of Alternate Carrier Gases for the Determination of Volatile Organic Compounds in Water by GC–MSThis study focuses on United States Environmental Protection Agency (US EPA) Method 524.3 for volatile organic compounds (VOCs) in water using gas chromatography–mass spectrometry (GC–MS).
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Online Identification of Flavones from Flos Chrysanthemi by LC–MS-IT-TOFThe use of medicinal herbs as alternative treatment methods continues to grow. With this escalating use has come an increasing interest in determining the chemical compositions of these herbs in order to obtain a better understanding of their makeup and effects. In this study, Flos Chrysanthemi, a commonly used traditional Chinese medicine that has been cultivated for centuries, was analyzed to identify the main flavone compositions in one original breed of Flos Chrysanthemi (Hangbaiju) in China.
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Rapid Chemical Threat Identification by SPME-GC–TMSA person-portable gas chromatography–mass spectrometry (GC–MS) system employing a toroidal ion trap mass spectrometry (TMS) detector was used to analyze chemical threat related compounds. Introduction of analytes into the heated injector of the instrument was by solid-phase microextraction (SPME), and fast resistive heating of a low thermal mass (LTM) gas chromatography column assembly provided rapid analysis times. Methodology for positive identification of chemical threats can combine chromatographic retention time, comparison to traditional electron ionization mass spectral libraries, and observation of expected pseudomolecular ions produced through self-chemical ionization. Methods are discussed for sampling by SPME with GC–MS analysis in the field to measure airborne analyte concentrations.
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Magnet or Cell? A Comparison of High-Resolution Sector Field ICP-MS and Collision–Reaction Cell Quadrupole ICP-MSInductively coupled plasma–mass spectrometry (ICP-MS) is a mature method that offers reliable measurements across almost the entire periodic table. It has been established as the key methodology for investigating elemental concentrations, which play a central role in biological, environmental, chemical, and industrial processes. ICP-MS is capable of performing multielemental analyses in a single analytical run, achieving an overall productivity of more than 50 samples/h. The method also delivers lower detection limits compared to graphite furnace atomic absorption (GFAA) or inductively coupled plasma–optical emission spectrometry (ICP-OES).
Latest:
Online Identification of Flavones from Flos Chrysanthemi by LC–MS-IT-TOFThe use of medicinal herbs as alternative treatment methods continues to grow. With this escalating use has come an increasing interest in determining the chemical compositions of these herbs in order to obtain a better understanding of their makeup and effects. In this study, Flos Chrysanthemi, a commonly used traditional Chinese medicine that has been cultivated for centuries, was analyzed to identify the main flavone compositions in one original breed of Flos Chrysanthemi (Hangbaiju) in China.
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A Study of Matrix Effects on Multiply Charged CompoundsIn preclinical development, the absolute quantification of peptides in biological matrices becomes a challenge due to the limited availability of stable label internal standards and affinity-based cleanup. This puts a renewed emphasis on matrix effects, especially for the bioanalysis of hydrophobic peptides. While the impact of matrix effects has been studied for extensively singly charged small molecules, their effect on multiply charged compounds has yet to be characterized fully. This article discusses initial results from matrix effect experiments in relation to the bioanalysis of hydrophobic peptides and techniques used to minimize matrix effects.
