Abundance normalization

Metastable ions yield valuable information on fragmentation in mass spectrometry, providing insight into molecular structure. In electron ionization, metastable ions appear naturally along with the much more abundant normal ions. Abundances of metastable ions can be enhanced by collisionally induced decomposition. 

The demand for aviation gasoline during World War II was so great that isobutanc from alkylation feedstock was insufficient. This deficiency was remedied by isomerization of abundant normal butane into isobutane using the isomerization catalyst aluminum chloride on alumina promoted by hydrogen chloride gas. 

Elemental abundances, normalized to Mg and Cl chondrites, for two groups of primitive achondrites (acapulcoites and winonaites) that experienced low degrees of partial melting. These abundances are similar to chondritic abundances (average H-chondrite composition is illustrated). Modified from Mittlefehldt (2004). 

Figure 5.2 Noble gas abundance (normalized to 36Ar) relative to air abundance. Data are from Table 5.1. The noble gas adsorption curve on pulverized Allende meteorite (Fanale Cannon, 1972) is also shown for comparison.

Relative abundance normalization in per cent relative to the base peak. 

The formation of molecular ions takes place with a range of internal energies, and more than one fragmentation path is possible for a given molecule. The mass spectrum is given as a chart showing the ion abundance (normalized to the most abundant ion) versus m/z of the fragments. For the interpretation of the mass spectra, two main questions should be answered, namely ... 

Figure 1. Relative elemental abundances, normalized to silicon, in the cosmic ray nuclei, and in the material of the solar system.

When the nucleus under study has poor abundance, such as for carbon-13, the cross polarization technique is used. This uses a complex pulse sequence to transfer the polarization from a nucleus with high abundance (normally hydrogen, but phosphorus and aluminium are also used) to the second nucleus, enhancing its signal. 

Fig. 28. Distribution of the r-nuclide abundances derived for a breeze solution obtained with a PNS mass of 1.5M , an initial electron fraction Ye = 0.48, and different values of the mass loss rate (in units of 10-5 M /s). The upper curve corresponds to the SoS r-nuclide abundances normalized to Xi = 1 (see [24] for details, particularly on the selected breeze solution)...

The selected concentrations for the Orgueil meteorite, considered as most representative for the Cl chondrites, are listed in Table 2 details about the data sources are in LPG09. Concentrations are given as parts per million (ppm) by mass (10,000 ppm = 1 mass%). Corresponding atomic abundances normalized to 106 Si atoms (the cosmochemical abundance scale ) are listed as well. 

The topology of water clusters observed under supercritical conditions can also be easily analyzed. In this analysis, we do not make any distinction between donor and acceptor types of hydrogen bonds originating at a particular water molecule. Thus, every molecule is depicted as a structureless dot in Figure 16, where all observable topological types of 3-, 4-, and 5-mers are shown along with their relative abundances (normalized as a fraction of molecules participating in clusters of certain type) under several supercritical thermodynamic conditions listed below in Tables 4 and 5. 

Observed abundances normalized to that of water ice (=100). W33A and NGC 7538-IRS 9 are two luminous protostars which span the observed range in interstellar ice composition. The abundances for the comets are an average of those observed for comets Hyakutake and Hale-Bopp. 

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