When.com Web Search

  1. Ads

    related to: positive ion mass spectrometry

Search results

  1. Results From The WOW.Com Content Network
  2. Mass spectrometry - Wikipedia

    en.wikipedia.org/wiki/Mass_spectrometry

    Mass spectrometry data analysis is specific to the type of experiment producing the data. General subdivisions of data are fundamental to understanding any data. Many mass spectrometers work in either negative ion mode or positive ion mode. It is very important to know whether the observed ions are negatively or positively charged.

  3. Direct analysis in real time - Wikipedia

    en.wikipedia.org/wiki/Direct_analysis_in_real_time

    In mass spectrometry, direct analysis in real time (DART) is an ion source that produces electronically or vibronically excited-state species from gases such as helium, argon, or nitrogen that ionize atmospheric molecules or dopant molecules. The ions generated from atmospheric or dopant molecules undergo ion-molecule reactions with the sample ...

  4. Chemical ionization - Wikipedia

    en.wikipedia.org/wiki/Chemical_ionization

    Peroxynitrate chemical ionization mass spectrometer at the US National Oceanic and Atmospheric Administration. CI mass spectrometry is a useful tool in structure elucidation of organic compounds. [3] This is possible with CI, because formation of [M+1] + eliminates a stable molecule, which can be used to guess the functional groups present. [3]

  5. Ion source - Wikipedia

    en.wikipedia.org/wiki/Ion_source

    The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine the elemental, isotopic, or molecular composition of the surface to a depth of 1 to 2 nm. In a liquid metal ion source (LMIS), a metal (typically gallium ) is heated to the liquid state and provided at the end of a capillary or a needle.

  6. Mass spectrum - Wikipedia

    en.wikipedia.org/wiki/Mass_spectrum

    A mass spectrum is a histogram plot of intensity vs. mass-to-charge ratio (m/z) in a chemical sample, [1] usually acquired using an instrument called a mass spectrometer. Not all mass spectra of a given substance are the same; for example, some mass spectrometers break the analyte molecules into fragments ; others observe the intact molecular ...

  7. Secondary ion mass spectrometry - Wikipedia

    en.wikipedia.org/.../Secondary_ion_mass_spectrometry

    Secondary-ion mass spectrometry (SIMS) is a technique used to analyze the composition of solid surfaces and thin films by sputtering the surface of the specimen with a focused primary ion beam and collecting and analyzing ejected secondary ions. The mass/charge ratios of these secondary ions are measured with a mass spectrometer to determine ...

  8. Electrospray ionization - Wikipedia

    en.wikipedia.org/wiki/Electrospray_ionization

    Electrospray ionization is the ion source of choice to couple liquid chromatography with mass spectrometry (LC-MS). The analysis can be performed online, by feeding the liquid eluting from the LC column directly to an electrospray, or offline, by collecting fractions to be later analyzed in a classical nanoelectrospray-mass spectrometry setup.

  9. Selected reaction monitoring - Wikipedia

    en.wikipedia.org/wiki/Selected_reaction_monitoring

    The ion is selected in the second mass spectrometry stage MS2 then undergoes further fragmentation to form ion D + which is selected in the third mass spectrometry stage MS3 and detected. Multiple reaction monitoring (MRM) is the application of selected reaction monitoring to multiple product ions from one or more precursor ions, [3] [4] for ...