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The monoisotopic mass is very useful when analyzing small organic compounds since compounds with similar weights will not be differentiated if the nominal mass is used. For example, when comparing tyrosine which has a molecular structure of C 9 H 11 NO 3 with a monoisotopic mass of 182.081 Da and methionine sulphone C 5 H 11 NO 4 S which ...
The monoisotopic mass is the sum of the masses of the atoms in a molecule using the unbound, ground-state, rest mass of the principal (most abundant) isotope for each element. [12] [5] The monoisotopic mass of a molecule or ion is the exact mass obtained using the principal isotopes. Monoisotopic mass is typically expressed in daltons.
The mass of b 2-ion = mass of two amino acid residues + 1. Table 2. Mass of b2-ions in peptide fragmentation [16] Identify a sequence ion series by the same mass difference, which matches one of the amino acid residue masses (see Table 1). For example, mass differences between a n and a n-1, b n and b n-1, c n and c n-1 are the same.
Loss on ignition (LOI) is a test used in inorganic analytical chemistry and soil science, particularly in the analysis of minerals and the chemical makeup of soil. It consists of strongly heating a sample of the material at a specified temperature, allowing volatile substances to escape, until its mass ceases to change. This may be done in air ...
The mass of the peptide or protein is the sum of the residue masses plus the mass of water (Monoisotopic mass = 18.01056 Da; average mass = 18.0153 Da). The residue masses are calculated from the tabulated chemical formulas and atomic weights. [11]
Monoisotopic mass is the sum of the masses of the atoms in a molecule using the most abundant isotope for each element; Monoisotopic element is one of the 26 chemical elements which have only one stable isotope
Gravimetric analysis describes a set of methods used in analytical chemistry for the quantitative determination of an analyte (the ion being analyzed) based on its mass. The principle of this type of analysis is that once an ion's mass has been determined as a unique compound, that known measurement can then be used to determine the same analyte's mass in a mixture, as long as the relative ...
Nitrogen-15, or 15 N, is often used in agricultural and medical research, for example in the Meselson–Stahl experiment to establish the nature of DNA replication. [12] An extension of this research resulted in development of DNA-based stable-isotope probing, which allows examination of links between metabolic function and taxonomic identity of microorganisms in the environment, without the ...