The Relative Atomic Mass has to take into account the abundance of each isotope - which is why the answer is generally not a whole number (integer) and why the definition contains the phrase "weighted mean". Relative Isotopic Mass is the mass of one particular isotope. ...The Relative Atom...
(Chemistry) the sum of all the relative atomic masses of the atoms in a molecule; the ratio of the average mass per molecule of a specified isotopic composition of a substance to one-twelfth the mass of an atom of carbon-12. Symbol:MrAbbreviation:r.m.m.Former name:molecular weight ...
In Comprehensive Analytical Chemistry, 1991 9.4.1 Principle of the Method In mass spectrometry, neutral molecules are converted into molecular ions; in the presence of excess internal energy, these ions can split into charged fragments and radicals. The charged species (molecular and fragment ions) ...
Following standard ion-exchange chemistry42, samples were precipitated as hydroxides, converted to BeO and then packed in cathodes with niobium. The 10Be/9Be ratios were measured at the Center for Accelerator Mass Spectrometry at Lawrence Livermore National Laboratory. Samples ran with high 9Be ...
In stellar evolution theory, the fractional abundance of H by mass is known as X, that of He is known as Y, and that of all other elements are known as Z. In stars, the abundances are determined from the strengths of absorption lines in the spectrum combined with other parameters in ...
The samples were converted to CO at 1,350 °C using pyrolysis-type elemental analyser (TC/EA, Thermo Fisher, Germany) interfaced to an isotope ratio mass spectrometer (Delta V Advantage, Thermo Fisher, Germany). The 18O/16O ratio was expressed in delta (d18O) notation with reference to...
Shotgun two-dimensional high performance liquid chromatography-tandem mass spectrometry (2D-HPLC-MS/MS) was used to determine protein relative abundance indexes (RAI), calculated as the number of spectral counts (SpC) divided by molecular mass (Mr) of protein, in exponential phase cell-free ...
Relative risks of groundwater-quality degradation near oil fields in California's Coastal basins (nine oil fields), western San Joaquin Valley (two fields), and eastern SJV (one field) were estimated by examining spatial and temporal patterns in chemical and isotopic data in the context of groun...
This chapter gives a comprehensive coverage of various current MS and fluorescence-based strategies for protein quantification, which have reported over the last five years. Most of these strategies rely on the combination of chemical/isotopic labeling, proteolysis, separation, and MS or fluorescence ...