Nitrogen-15 (¹⁵N)

Data nuklida

Unsur

Nitrogen (N, Z = 7)

Nomor massa (A)

15

Proton (Z)

7

Neutron (N)

8

Massa atom

15.00010889827 ± 0.00000000062 u

Waktu paruh

Stabil

Mode peluruhan

Tidak meluruh

Kelimpahan alami

[0.003 37, 0.004 22]

Tahun penemuan

1929

Sumber data

IAEA Atomic Mass Data Center (NUBASE) and IUPAC CIAAW, via PubChem

Kegunaan isotop nitrogen

• Isotopic fractionation can cause the isotope-amount ratio n(15N)/n(14N) to increase systematically through food chains through assimilation of nitrogen compounds in biomolecules such as proteins. When lower-order organisms are ingested by higher-order organisms, 15N may be selectively retained and 14N may be selectively excreted such that higher-order organisms tend to have higher n(15N)/n(14N) ratios than their food sources. Isotopic fractionation occurs as a result of assimilation, storage, and excretion of proteins and other nitrogen compounds. Biologists can use isotope-amount ratio n(15N)/n(14N) measurements to test hypotheses about predator-prey relations and detect disruptions to trophic structure of ecosystems that might be caused by toxic contaminants, invasive species, or harvesting of organisms. Similar principles are used to detect differences in diets among animals, including humans, both today and in the distant past,,. Artificially enriched 15N tracers are used to study movement and transformation of nitrogen in biological and environmental systems, such as the uptake and loss of nitrogen fertilizers by crops (Fig. IUPAC.7.1). A common experiment involves introducing an isotopically labeled compound into the environment and then analyzing various samples taken from the environment for the presence of the enriched isotope to determine where the labeled compound moved and whether it transformed into other compounds (Fig. IUPAC.7.2). Artificially enriched 15N is used to study uptake and dispersal of nitrogen in feed supplies used in food production industries such as aquaculture.
• The stable isotopes of nitrogen are subject to isotopic fractionation by physical, chemical, and biological processes. Variations in the isotope-amount ratio n(15N)/n(14N) are substantial (Fig. IUPAC.7.3) and commonly are used to study Earth-system processes, especially those related to biology because nitrogen is a major nutrient for growth. For example, isotope fractionation occurs when dissolved solutes, such as nitrate (NO3 -), are transformed to more reduced compounds (i.e. nitrogen gas) because nitrate with higher 14N abundances tends to be more readily broken down. This leaves the residual unreacted nitrate with a higher n(15N)/n(14N) ratio than the initial ratio prior to reaction. Changes in the isotopic composition of biologically reactive compounds can be used to detect such reactions in aquatic environments, which are important mechanisms for removing reactive contaminants like nitrate,. Variations in the isotope-amount ratio n(15N)/n(14N) are used to determine sources of nitrogen contamination in the atmosphere, oceans, groundwater, and rivers, where the isotopic composition of a contaminant molecule preserves evidence of the nitrogen sources and processes involved in its creation. An example is nitrate derived from artificial fertilizer, manure, power-plant emissions, or natural sources,,. Artificially enriched 15N tracers have been used to determine rates of movement and natural remediation of nitrogen-bearing contaminants in aquifers and rivers,.

Isotop nitrogen lainnya

¹⁰N, ¹¹N, ¹²N, ¹³N, ¹⁴N, ¹⁶N, ¹⁷N, ¹⁸N, ¹⁹N, ²⁰N, ²¹N, ²²N, ²³N, ²⁴N, ²⁵N

Pelajari

Kimia inti Simulasi peluruhan ¹⁵N Bagan nuklida