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  2. Gas chromatography–mass spectrometry - Wikipedia

    en.wikipedia.org/wiki/Gas_chromatography–mass...

    For the analysis of volatile compounds, a purge and trap (P&T) concentrator system may be used to introduce samples. The target analytes are extracted by mixing the sample with water and purge with inert gas (e.g. Nitrogen gas) into an airtight chamber, this is known as purging or sparging.

  3. Headspace gas chromatography for dissolved gas measurement

    en.wikipedia.org/wiki/Headspace_Gas...

    One of the most widely used methods for headspace analysis is described by the United States Environmental Protection Agency (USEPA). Originally developed by the R.S. Kerr USEPA Laboratory in Ada, Oklahoma as a "high quality, defendable, and documented way to measure" methane, ethane, and ethene, [7] [8] RSKSOP-175 is a standard operating procedure (SOP) and an unofficial method employed by ...

  4. Gas chromatography - Wikipedia

    en.wikipedia.org/wiki/Gas_chromatography

    Gas chromatography (GC) is a common type of chromatography used in analytical chemistry for separating and analyzing compounds that can be vaporized without decomposition. Typical uses of GC include testing the purity of a particular substance, or separating the different components of a mixture. [ 1 ]

  5. Forensic toxicology - Wikipedia

    en.wikipedia.org/wiki/Forensic_toxicology

    Gas chromatography-mass spectrometry is a widely used analytical technique for the detection of volatile compounds. Ionization techniques most frequently used in forensic toxicology include electron ionization (EI) or chemical ionization (CI), with EI being preferred in forensic analysis due to its detailed mass spectra and its large library of ...

  6. Drug test - Wikipedia

    en.wikipedia.org/wiki/Drug_test

    If the urine screen is positive then another aliquot of the sample is used to confirm the findings by gas chromatography—mass spectrometry (GC-MS) or liquid chromatography - mass spectrometry methodology. If requested by the physician or employer, certain drugs are screened for individually; these are generally drugs part of a chemical class ...

  7. Silylation - Wikipedia

    en.wikipedia.org/wiki/Silylation

    The introduction of a silyl group(s) gives derivatives of enhanced volatility, making the derivatives suitable for analysis by gas chromatography and electron-impact mass spectrometry (EI-MS). For EI-MS, the silyl derivatives give more favorable diagnostic fragmentation patterns of use in structure investigations, or characteristic ions of use ...

  8. gas chromatography Pyrolysis GC/MS chromatogram of mahogany wood analyzed with OpenChrom Pyrolysis–gas chromatography–mass spectrometry is a method of chemical analysis in which the sample is heated to decomposition to produce smaller molecules that are separated by gas chromatography and detected using mass spectrometry .

  9. Internal standard - Wikipedia

    en.wikipedia.org/wiki/Internal_standard

    In gas chromatography-mass spectrometry (GC-MS), deuterated compounds with similar structures to the analyte commonly act as effective internal standards. [8] However, there are non-deuterated internal standards such as norleucine, which is popular in the analysis of amino acids because it can be separated from accompanying peaks. [9] [10] [11]