Phosphorus-32

<h2 id="decay">Decay</h2>
<p>Phosphorus-32 has a short <a href="/facts/Half-life/kGVH8BAB">half-life</a> of 14.268 days and decays into <a href="/facts/Sulfur-32/08Qs8w3o">sulfur-32</a> by <a href="/facts/Beta_decay/vxTBlckp">beta decay</a><a class="footnote-ref" id="fnref:1" href="#fn:1"><sup>1</sup></a> as shown in this nuclear equation:
</p>
<table><tbody><tr><td>3215P</td><td>→</td><td>3216S1+</td><td>+</td><td><a href="/facts/Electron/L0KBo5cW">e−</a></td><td>+</td><td><a href="/facts/Electron_antineutrino/e5hQPWIQ">νe</a></td></tr></tbody></table>
<p>1.709 <a href="/facts/MeV/YMT1fqX9">MeV</a> of energy is released from this decay.<a class="footnote-ref" id="fnref:2" href="#fn:2"><sup>2</sup></a> The kinetic energy of the <a href="/facts/Electron/L0KBo5cW">electron</a> varies with an average of approximately 0.5 MeV and the remainder of the energy is carried by the nearly undetectable <a href="/facts/Electron_antineutrino/e5hQPWIQ">electron antineutrino</a>. In comparison to other beta radiation-emitting nuclides, the electron is moderately energetic. It is blocked by around 1 m of air or 5 mm of <a href="/facts/Acrylic_glass/CnCRBo5F">acrylic glass</a>.
</p><p>The sulfur-32 nucleus produced is in the <a href="/facts/Ground_state/ML7cfCug">ground state</a>, so there is no additional <a href="/facts/Gamma_ray/5Drf913J">gamma ray</a> emission.
</p>
<h2 id="production">Production</h2>

<p>Phosphorus-32 has important uses in <a href="/facts/Medicine/2fnp90Je">medicine</a>, <a href="/facts/Biochemistry/fa2pWEBp">biochemistry</a> and <a href="/facts/Molecular_biology/YgqU35ub">molecular biology</a>. It only exists naturally on earth in very small amounts and its short half-life means useful quantities have to be produced synthetically. Phosphorus-32 can be generated synthetically by <a href="/facts/Neutron_source/4BTQAu9l">irradiation</a> of sulfur-32 with moderately fast neutrons as shown in this nuclear equation:
</p>
<table><tbody><tr><td>3216S</td><td>+</td><td><a href="/facts/Neutron/oRCM1geb">n</a></td><td>→</td><td>3215P +</td><td><a href="/facts/Proton/clCjepXP">p</a></td></tr></tbody></table>
<p>The sulfur-32 nucleus captures the neutron and emits a proton, reducing the <a href="/facts/Atomic_number/bgAr581S">atomic number</a> by one while maintaining the <a href="/facts/Mass_number/VyBbJ1oI">mass number</a> of 32.
</p><p>This reaction has also been used to determine the yield of nuclear weapons.<a class="footnote-ref" id="fnref:3" href="#fn:3"><sup>3</sup></a><a class="footnote-ref" id="fnref:4" href="#fn:4"><sup>4</sup></a>
</p>
<h2 id="uses">Uses</h2>
<p>Phosphorus is abundant in biological systems and, as a radioactive isotope, is almost chemically identical with stable isotopes of the same element. Phosphorus-32 can be used to <a href="/facts/Radiolabel/0210Jncn">label</a> biological molecules. The beta radiation emitted by the phosphorus-32 is sufficiently penetrating to be detected outside the organism or tissue which is being analysed
</p>
<h3>Biochemistry and molecular biology</h3>
<p>The <a href="/facts/Metabolic_pathway/8Py8HKJd">metabolic pathways</a> of organisms extensively use phosphorus in the generation of different biomolecules within the cell. Phosphorus-32 finds use for analysing metabolic pathways in <a href="/facts/Pulse_chase/rhKB0fSJ">pulse chase</a> experiments, where a culture of cells is treated for a short time with a phosphorus-32-containing substrate. The sequence of chemical changes, which happen to the substrate, can then be traced by detecting which molecules contain the phosphorus-32 at multiple time points following the initial treatment.
</p><p><a href="/facts/DNA/nB89Iauz">DNA</a> and <a href="/facts/RNA/HxPeNfNj">RNA</a> contain a large quantity of phosphorus in the <a href="/facts/Phosphodiester/fCjTAnxa">phosphodiester</a> linkages between <a href="/facts/Nucleobase/zj1Vl9Qh">bases</a> in the <a href="/facts/Oligonucleotide/Gc99fPnC">oligonucleotide</a> chain. DNA and RNA can therefore be tracked by replacing the phosphorus with phosphorus-32. This technique is extensively used in <a href="/facts/Southern_blot/HXrr0Gz3">Southern blot</a> and <a href="/facts/Northern_blot/pRUrdy2n">Northern blot</a> analysis of DNA and RNA samples respectively. In both cases, a phosphorus-32-containing DNA probe hybridises to its complementary sequence, where it appears in a gel. Its location can then be detected by photographic film.
</p>
<h3>Plant sciences</h3>
<p>Phosphorus-32 is used in <a href="/facts/Plant_sciences/PaIRoxnb">plant sciences</a> for tracking a plant's uptake of <a href="/facts/Fertiliser/ysh3r6NJ">fertiliser</a> from the <a href="/facts/Root/Hk7ucczM">roots</a> to the <a href="/facts/Leaves/1m6wCNTg">leaves</a>.  The phosphorus-32-labelled fertiliser is given to the plant <a href="/facts/Hydroponic/g96g3ypl">hydroponically</a>, or via water in the soil, and the usage of the phosphorus can be mapped from the emitted beta radiation. The information gathered by mapping the <a href="/facts/Fertiliser/ysh3r6NJ">fertiliser</a> uptake shows how the plant takes up and uses the phosphorus from fertiliser.<a class="footnote-ref" id="fnref:5" href="#fn:5"><sup>5</sup></a>
</p>
<h2 id="safety">Safety</h2>
<p>The high energy of emitted beta particles and the low half-life of phosphorus-32 make it potentially harmful; Its molar activity is 338.61 TBq/mmol (9151.6 Ci/mmol) and its <a href="/facts/Specific_activity/KIv7s4N4">specific activity</a> is 10.590 EBq/kg (286.22 kCi/g). Typical safety precautions when working with phosphorus-32 include wearing a personal <a href="/facts/Dosimeter/lc6K3MWK">dosimeter</a> to monitor exposure and an <a href="/facts/Acrylic_glass/CnCRBo5F">acrylic</a> or <a href="/facts/Perspex/CnCRBo5F">perspex</a> radiation shield to protect the body. Dense shielding, such as lead, is less effective due to the high-energy <a href="/facts/Bremsstrahlung/XafQtbx6">bremsstrahlung</a> produced by the interaction of the beta particle and the shielding. Because the beta radiation from phosphorus-32 is blocked by around 1 m of air, it is also advisable to wear dosimeters on the parts of the body, for example the <a href="/facts/Finger/v2gDEpbp">fingers</a>, which come into close contact with the phosphorus-32-containing sample.
</p>

<h2 id="external-links">External links</h2>
<ul><li><a href="http://www.nucmedtutorials.com/dwmodesdecay/modes3.html">β- DECAY, β+ DECAY, ELECTRON CAPTURE, & ISOMERIC TRANSITION</a></li></ul>

<h2 id="references">References</h2>

<ol>
<li id="fn:1"><p>Audi, G.; Kondev, F. G.; Wang, M.; Huang, W. J.; Naimi, S. (2017). "The NUBASE2016 evaluation of nuclear properties" (PDF). Chinese Physics C. 41 (3): 030001. Bibcode:2017ChPhC..41c0001A. doi:10.1088/1674-1137/41/3/030001. <a href="https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf" target="_blank">https://www-nds.iaea.org/amdc/ame2016/NUBASE2016.pdf</a> <a href="#fnref:1" class="footnote-back-ref">↩</a></p></li>
<li id="fn:2"><p>"Phosphorus 32". www.site.uottawa.ca:4321. Archived from the original on 2014-02-22. <a href="https://web.archive.org/web/20140222044331/http://www.site.uottawa.ca:4321/astronomy/index.html" target="_blank">https://web.archive.org/web/20140222044331/http://www.site.uottawa.ca:4321/astronomy/index.html</a> <a href="#fnref:2" class="footnote-back-ref">↩</a></p></li>
<li id="fn:3"><p>Kerr, George D.; Young, Robert W.; Cullings, Harry M.; Christy, Robert F. (2005). "Bomb Parameters" (PDF). In Robert W. Young, George D. Kerr (ed.). Reassessment of the Atomic Bomb Radiation Dosimetry for Hiroshima and Nagasaki – Dosimetry System 2002. The Radiation Effects Research Foundation. pp. 42–43. Archived from the original (PDF) on 2015-08-10. Retrieved 2014-03-13. <a href="https://web.archive.org/web/20150810210007/http://www.rerf.or.jp/shared/ds02/pdf/chapter01/cha01-p42-61.pdf" target="_blank">https://web.archive.org/web/20150810210007/http://www.rerf.or.jp/shared/ds02/pdf/chapter01/cha01-p42-61.pdf</a> <a href="#fnref:3" class="footnote-back-ref">↩</a></p></li>
<li id="fn:4"><p>Malik, John (September 1985). "The Yields of the Hiroshima and Nagasaki Explosions" (PDF). Los Alamos National Laboratory. Retrieved March 9, 2014. <a href="https://www.osti.gov/manhattan-project-history/publications/LANLHiroshimaNagasakiYields.pdf" target="_blank">https://www.osti.gov/manhattan-project-history/publications/LANLHiroshimaNagasakiYields.pdf</a> <a href="#fnref:4" class="footnote-back-ref">↩</a></p></li>
<li id="fn:5"><p>Singh, B., Singh, J., & Kaur, A. (2013). Applications of Radioisotopes in Agriculture. International Journal of Biotechnology and Bioengineering Research,4(3), 167-174. <a href="#fnref:5" class="footnote-back-ref">↩</a></p></li>
</ol>

Phosphorus-32 open-in-new

Phosphorus-32