Kalsium-44 (⁴⁴Ca)

Data nuklida

Unsur

Kalsium (Ca, Z = 20)

Nomor massa (A)

44

Proton (Z)

20

Neutron (N)

24

Massa atom

43.955481489 ± 0.000000348 u

Waktu paruh

Stabil

Mode peluruhan

Tidak meluruh

Kelimpahan alami

0.020 86(110)

Tahun penemuan

1922

Sumber data

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

Kegunaan isotop kalsium

• Molecules, atoms, and ions of the stable isotopes of calcium possess slightly different physical and chemical properties, and they commonly will be fractionated during physical, chemical, and biological processes, giving rise to variations in isotopic abundances and in atomic weights (Fig. IUPAC.20.1). The isotope-amount ratio n(44Ca)/n(40Ca) is used to quantify the calcium cycle (sources and sinks of calcium) in the ocean. Calcium isotopes fractionate (separate) in terrestrial and marine environments owing to biological and inorganic processes, which discriminate against heavy calcium isotopes. The calcification process controls the removal of calcium from the ocean, which is mostly balanced by hydrothermal and riverine calcium input. Calcium has a long residence time, symbol τ, in seawater (τCa about 1 to 2 million years) relative to the short mixing time of the global ocean (about 1000 years), which has allowed the calcium isotopic composition of modern seawater to homogenize globally. This was likely the case in the geological past as well, which makes the n(44Ca)/n(40Ca) ratio useful when quantifying the oceanic calcium cycle,. The isotope-amount ratio n(44Ca)/n(40Ca) has been used to trace sources of calcium in soil and river water. The isotope-amount ratio n(44Ca)/n(40Ca) ratio of calcium carbonate may serve as a paleothermometer to determine seawater temperatures in the past, making use of the temperature-dependent isotopic fractionation between 40Ca and 44Ca,. The radioactive isotope 45Ca (half-life of 163 days) is used to study calcium behavior in soils, detergents, water-purification systems, and glassy materials. 45Ca is introduced into a system and monitored to measure various types of calcium responses within the system and to investigate how calcium of one matrix may interact with another (i.e. calcium of soil mixing with that of fertilizers). 45Ca has been used to investigate the transport of contaminants in groundwater through the unsaturated zone.
• Stable isotopes of calcium (42Ca, 44Ca, 46Ca, and 48Ca) and radioisotopes of calcium (45Ca and 47Ca, with a half-life of 109 h) can be used for tracing calcium uptake, utilization, and excretion in the body. For example, most of our knowledge on the efficiency by which calcium is absorbed in the intestine (bioavailability) comes from studies in which calcium in the diet was labeled with stable or radioactive isotopes. In such studies, the isotope-labeled food is ingested and fecal matter tested for the presence and quantity of unabsorbed isotope. When coupling oral ingestion of food labeled with one calcium isotope with an intravenous injection of a second calcium isotope, this technique can be used as a means to measure calcium absorption within the body by measuring excretion of both tracers in the urine. In a similar fashion, dietary absorption of magnesium and zinc can be studied,. Stable and radioactive isotopes are used in biomedical research and clinical practice to study disorders associated with calcium metabolism, in particular in relation to bone health and calcium accumulation in body tissues (vascular calcification, kidney stone formation). Stable isotope tracers have been used successfully to study bone calcium balance during space-flight and in-bed-rest studies. A long-living calcium radioisotope (41Ca), with a half-life of 9.9×104 years, has been used successfully for labeling of bone calcium to measure bone calcium turnover via urinary excretion of the tracer.

Isotop kalsium lainnya

³³Ca, ³⁴Ca, ³⁵Ca, ³⁶Ca, ³⁷Ca, ³⁸Ca, ³⁹Ca, ⁴⁰Ca, ⁴¹Ca, ⁴²Ca, ⁴³Ca, ⁴⁵Ca, ⁴⁶Ca, ⁴⁷Ca, ⁴⁸Ca, ⁴⁹Ca, ⁵⁰Ca, ⁵¹Ca, ⁵²Ca, ⁵³Ca, ⁵⁴Ca, ⁵⁵Ca, ⁵⁶Ca, ⁵⁷Ca, ⁵⁸Ca, ⁵⁹Ca, ⁶⁰Ca, ⁶¹Ca

Pelajari

Kimia inti Simulasi peluruhan ⁴⁴Ca Bagan nuklida