Results 201 to 210 of about 101,472 (247)
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Isotope-ratio-monitoring gas chromatography-mass spectrometry: methods for isotopic calibration
Organic Geochemistry, 1994In trial analyses of a series of n-alkanes, precise determinations of 13C contents were based on isotopic standards introduced by five different techniques and results were compared. Specifically, organic-compound standards were coinjected with the analytes and carried through chromatography and combustion with them; or CO2 was supplied from a ...
D A, Merritt, W A, Brand, J M, Hayes
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Isotope Ratio Measurements with Elemental-Mode Electrospray Mass Spectrometry
Analytical Chemistry, 1996The isotope ratio capabilities of an electrospray ionization source interfaced to a quadrupole mass spectrometer are described. With the instrument operated in the metal ion mode, isotope measurements of Ag, Tl, and Pb are conducted using elemental ions produced from 1 × 10(-)(4) M solutions of metal nitrates or acetates in methanol.
M E, Ketterer, J P, Guzowski
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High-precision liquid chromatography-combustion isotope ratio mass spectrometry
Analytical Chemistry, 1993Online liquid chromatography-combustion high-precision carbon isotope ratio mass spectrometry (LCC-IRMS) is demonstrated for the first time with a direct interface to the liquid source. The interface is based on a continuously coated moving wire which facilitates reproducible solvent removal and analyte combustion, followed by drying of the CO2 and ...
R J, Caimi, J T, Brenna
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Forensic applications of isotope ratio mass spectrometry—A review
Forensic Science International, 2006The key role of a forensic scientist is to assist in determining whether a crime has been committed, and if so, assist in the identification of the offender. Many people hold the belief that a particular item can be conclusively linked to a specific person, place or object. Unfortunately, this is often not achievable in forensic science.
Sarah, Benson +3 more
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Analytical Chemistry, 2014
Generally, compound-specific isotope analysis of steroids is carried out by gas chromatography combined with isotope ratio mass spectrometry. Thus, a derivatization of the steroids prior to the measurement is compulsory, and a correction of the isotopic data is often necessary.
Zhang, Lijun +8 more
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Generally, compound-specific isotope analysis of steroids is carried out by gas chromatography combined with isotope ratio mass spectrometry. Thus, a derivatization of the steroids prior to the measurement is compulsory, and a correction of the isotopic data is often necessary.
Zhang, Lijun +8 more
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Analytical Chemistry, 1991
The application of a combined gas chromatography/isotope ratio mass spectrometry (GC/IRMS) method for stable carbon isotope analysis of amino acid enantiomers is presented. Amino acids require derivatization prior to GC/IRMS analysis. Derivatization of amino acid standards of known stable carbon isotope compositions in conjunction with natural samples,
J. A. Silfer +3 more
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The application of a combined gas chromatography/isotope ratio mass spectrometry (GC/IRMS) method for stable carbon isotope analysis of amino acid enantiomers is presented. Amino acids require derivatization prior to GC/IRMS analysis. Derivatization of amino acid standards of known stable carbon isotope compositions in conjunction with natural samples,
J. A. Silfer +3 more
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Isotopic Analysis of Atmospheric Formaldehyde by Gas Chromatography Isotope Ratio Mass Spectrometry
Analytical Chemistry, 2006Little is known about the isotopic composition of formaldehyde in the atmosphere, a chemical intermediate in hydrocarbon oxidation. Here, we present a promising new method to analyze the carbon (delta 13C) and hydrogen (delta D) isotopic composition of atmospheric formaldehyde. The direct isotopic analytical technique described uses continuous-flow gas
Andrew L, Rice, Paul D, Quay
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Determination of Bromine Stable Isotopes Using Continuous-Flow Isotope Ratio Mass Spectrometry
Analytical Chemistry, 2005A new methodology for bromine stable isotope determination by continuous-flow isotope ratio mass spectrometry (CF-IRMS) was developed. The technique was tested on inorganic samples. Inorganic bromide was precipitated in the form of silver bromide by using silver nitrate in a standard methodology.
Orfan, Shouakar-Stash +2 more
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Memory effects in combining isotope ratio monitoring with isotope dilution mass spectrometry
Rapid Communications in Mass Spectrometry, 1999Combining isotope ratio monitoring with isotope dilution techniques provides very accurate results in the quantitative analysis of volatile organic chemical compounds by gas chromatography/mass spectrometry (GC/MS). However, this method requires that spikes highly enriched in (13)C be used.
, Dube, , Henrion, , Ohlendorf
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Applied gas chromatography coupled to isotope ratio mass spectrometry
Journal of Chromatography A, 1999Compound-specific isotope analysis (CSIA) by isotope ratio mass spectrometry (IRMS) following on-line combustion (C) of compounds separated by gas chromatography (GC) is a relatively young analytical method. Due to its ability to measure isotope distribution at natural abundance level with great accuracy and high precision, GC-C-IRMS has increasingly ...
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