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Mass spectrum. Electron ionization mass spectrum of toluene [1]. Note parent peak corresponding to molecular mass M = 92 (C 7 H 8+) and highest peak at M-1 = 91 (C 7 H 7+, quasi-stable tropylium cation). 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 ...
De novo peptide sequencing. In mass spectrometry, de novo peptide sequencing is the method in which a peptide amino acid sequence is determined from tandem mass spectrometry. Knowing the amino acid sequence of peptides from a protein digest is essential for studying the biological function of the protein. In the old days, this was accomplished ...
Appearance. Mass spectrometry (MS) is an analytical technique that is used to measure the mass-to-charge ratio of ions. The results are presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio. Mass spectrometry is used in many different fields and is applied to pure samples as well as complex mixtures.
Gas chromatography–mass spectrometry. Gas chromatography–mass spectrometry (GC–MS) is an analytical method that combines the features of gas-chromatography and mass spectrometry to identify different substances within a test sample. [1] Applications of GC–MS include drug detection, fire investigation, environmental analysis, explosives ...
An infrared spectroscopy correlation table (or table of infrared absorption frequencies) is a list of absorption peaks and frequencies, typically reported in wavenumber, for common types of molecular bonds and functional groups. [ 1 ][ 2 ] In physical and analytical chemistry, infrared spectroscopy (IR spectroscopy) is a technique used to ...
Mass chromatogram. A mass chromatogram is a representation of mass spectrometry data as a chromatogram, where the x-axis represents time and the y-axis represents signal intensity. [1] The source data contains mass information; however, it is not graphically represented in a mass chromatogram in favor of visualizing signal intensity versus time.
The Kendrick mass is defined by setting the mass of a chosen molecular fragment, typically CH 2, to an integer value in amu (atomic mass units). It is different from the IUPAC definition, which is based on setting the mass of 12 C isotope to exactly 12 amu. The Kendrick mass is often used to identify homologous compounds differing only by a ...
The precursor ions then dissociate or react in an electric field-free region between the two sectors. The ratio of the kinetic energy to charge of the product ions are analyzed by scanning the electric sector field E. The width of the product ion spectrum peaks is related to the kinetic energy release distribution for the dissociation process. [4]