relative abundance

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relative abundance

A term defined in the context of mass spectrometry as the measured intensity of an ion beam at the designated m/z value.

Relative abundance refers to the practice of assigning to the most abundant ion in a measured and plotted mass spectrum a relative abundance of 100% and normalising all other ion abundances to that value. To be precise, ion beams are measured in intensity, and ions in abundance.
References in periodicals archive ?
Piccolo MC, Neill C, Melillo JM, Cerri CC, Steudler PA (1996) [sup.15]N natural abundance in forest and pasture soils of the Brazilian Amazon Basin.
For natural abundance [sup.13]C analyses of soil and plant materials, the analytical procedure described by Krull and Skjemstad (2003) was used.
Worryingly, this natural abundance is now on a watch list of biodiversity hot spots.
Change in land use from [C.sub.3]-dominant vegetation to [C.sub.4]-dominant vegetation provides analytical tools to differentiate [C.sub.3]-derived C (native vegetation) from [C.sub.4]-derived C in the whole SOC and C fractions, since natural abundance [sup.13]C isotopic signatures of the former ([delta][sup.13]C values, -30%o to -24%o) differ from those of the latter ([delta][sup.13]C values, 14%o to - 11%o) (Balesdent et al.
Polyolefins were only present as blends with starch; in spite of the natural abundance of polyisoprenoids, natural rubber was not mentioned.
The aims of the study were to examine the impact of stock on soil [sup.15]N natural abundance ([[Delta].sup.15]N) within the context of former seabird breeding, and to relate the [sup.15]N enrichment of plant material to both stock activity and soil [sup.15]N enrichment.
The [[Delta].sup.18]O value is defined as a measure of the [sup.18]O content of a sample, but is reported not as a concentration, but rather as a normalized difference from the natural abundance of [sup.18]O in seawater.
Natural abundance.--For each species, we summed catches for the two years of sampling that took place before the fragmentation treatment was applied.
In hopes of restoring the toads' natural abundance, Johnson is directing a species survival effort -- the only such program that the American Association of Zoological Parks and Aquariums has undertaken for amphibians.