-->

Saturday, May 26, 2018

What's an Isotope? - Phosphorus - YouTube
src: i.ytimg.com

Although phosphorus (15P) has 23 isotopes from 24P to 46P, only one of these isotopes is stable 31P; as such, it is considered a monoisotopic element. The longest-lived radioactive isotopes are 33P with a half-life of 25.34 days and 32P with a half-life of 14.263 days. All others have lived under 2.5 minutes, most under a second. The least stable is 25P with a half-life shorter than 30 nanoseconds--the half-life of 24P is unknown.


Video Isotopes of phosphorus



Radioactive isotopes

Phosphorus-32

32P, a beta-emitter (1.71 MeV) with a half-life of 14.3 days, is used routinely in life-science laboratories, primarily to produce radiolabeled DNA and RNA probe, e.g. for use in Northern blots or Southern blots. Because the high-energy beta particles produced penetrate skin and corneas, and because any 32P ingested, inhaled, or absorbed is readily incorporated into bone and nucleic acids, OSHA requires that a lab coat, disposable gloves, and safety glasses or goggles be worn when working with 32P, and that working directly over an open container be avoided in order to protect the eyes. Monitoring personal, clothing, and surface contamination is also required. In addition, due to the high energy of the beta particles, shielding this radiation with the normally used dense materials (e.g. lead), gives rise to secondary emission of X-rays via a process known as bremsstrahlung, meaning braking radiation. Therefore, shielding must be accomplished with low-density materials, e.g. Plexiglas, Lucite, plastic, wood, or water.

Phosphorus-33

33P, a beta-emitter (0.25 MeV) with a half-life of 25.4 days. It is used in life-science laboratories in applications in which lower energy beta emissions are advantageous such as DNA sequencing. Phosphorus-33 can be used to label nucleotides. It is less energetic than 32P, giving a better resolution. A disadvantage is its higher cost compared to 32P, as most of the bombarded 31P will have acquired only one neutron, while only some will have acquired two or more. Its maximum specific activity is 5118 Ci/mol.


Maps Isotopes of phosphorus



List of isotopes

Notes

  • Values marked # are not purely derived from experimental data, but at least partly from systematic trends. Spins with weak assignment arguments are enclosed in parentheses.
  • Uncertainties are given in concise form in parentheses after the corresponding last digits. Uncertainty values denote one standard deviation, except isotopic composition and standard atomic mass from IUPAC, which use expanded uncertainties.

Identifying the Substance of Genes - ppt download
src: slideplayer.com


References

  • Isotope masses from:
    • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3-128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23. 
  • Isotopic compositions and standard atomic masses from:
    • J. R. de Laeter; J. K. Böhlke; P. De Bièvre; H. Hidaka; H. S. Peiser; K. J. R. Rosman; P. D. P. Taylor (2003). "Atomic weights of the elements. Review 2000 (IUPAC Technical Report)". Pure and Applied Chemistry. 75 (6): 683-800. doi:10.1351/pac200375060683. 
    • M. E. Wieser (2006). "Atomic weights of the elements 2005 (IUPAC Technical Report)". Pure and Applied Chemistry. 78 (11): 2051-2066. doi:10.1351/pac200678112051. Lay summary. 
  • Half-life, spin, and isomer data selected from the following sources. See editing notes on this article's talk page.
    • G. Audi; A. H. Wapstra; C. Thibault; J. Blachot; O. Bersillon (2003). "The NUBASE evaluation of nuclear and decay properties" (PDF). Nuclear Physics A. 729: 3-128. Bibcode:2003NuPhA.729....3A. doi:10.1016/j.nuclphysa.2003.11.001. Archived from the original (PDF) on 2008-09-23. 
    • National Nuclear Data Center. "NuDat 2.1 database". Brookhaven National Laboratory. Retrieved September 2005. 
    • N. E. Holden (2004). "Table of the Isotopes". In D. R. Lide. CRC Handbook of Chemistry and Physics (85th ed.). CRC Press. Section 11. ISBN 978-0-8493-0485-9. 

Biogeochemical cycling of phosphorus: Insights from oxygen isotope ...
src: www.ajsonline.org


External links

  • Phosphorus isotopes data from The Berkeley Laboratory Isotopes Project's


Source of article : Wikipedia