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About Isotopes

Isotopes are variants of chemical elements: while all isotopes of a given element contain the same number of protons, they vary in the number of neutrons they contain. Variation in neutron number produces chemically identical atoms with different masses, which can be exploited to allow tracing of specific individual atoms through a system.

Stable isotopes

Stable isotopes are generally defined as non-radioactive isotopic elements that do not decay over time. Radioactive isotopes may also be classified as stable isotopes when their half-lives are too long to be measured. These elements can often be found to occur in nature and include isotopes of carbon, nitrogen, hydrogen, oxygen, noble gases and metals. For example, three naturally occurring isotopes of hydrogen include protium (H) having one neutron, deuterium (2H) having two neutrons, and tritium having three neutrons.

Isotopically labeled compounds

Isotopically labelled compounds are compounds that incorporate isotopic elements within their molecular structure and are thus ‘labelled’ by the isotope. These compounds are used to study chemical and biochemical reactions, metabolic pathways or cellular transport. Specifically, isotope-labelled compounds are routinely used for a variety of applications including magnetic resonance imaging (MRI), spectroscopy, nuclear magnetic resonance (NMR), and geochemical analyses. An example of using an isotopic label includes replacing the most common isotope of hydrogen, protium, with deuterium to observe hydrogen exchange reactions in water.

Isotope separation methods

Distillation and Diffusion Processes

Distillation or diffusion are processes which are for enrichment used when there are relatively large mass differences between different isotopes of an element.

Centrifuge enrichment

Centrifuge processes for enrichment includes gas centrifugation and improvements upon the gas centrifuge techniques. This process involves rotating cylinders in order to move the heavier gas molecules containing a given isotope to the outer radius of the cylinder while collecting the lighter gas molecules containing the given isotope in the center of the cylinder.

Electromagnetic enrichment

Electromagnetic isotope separation processes involves first vaporizing the isotope containing molecules followed by ionizing the vapor with positively charged ions. A mass spectrometer, known as the Calutron, is then used to redirect a stream of cations onto a target for collection.

Other methods: laser enrichment, photochemical enrichment and plasma separation

Laser enrichment processes provide for lower energy inputs and thus more economical enrichment. One method currently under investigation is known as the Separation of Isotopes by Laser Excitiation (SILEX). Another laser method that is used to enrich uranium containing the 235U atom is known as molecular laser isotope separation (MLIS) which involves using infrared laser at UF6 molecules and a second laser to free a fluorine atom resulting in precipitation of the remaining UF5 compound out of the gas.

Plasma separation involves the principle of ion cyclotron resonance and uses superconducting magnets to energize a given isotope in plasma consisting of an ionic mixture.

Applications

Medical

Metabolic studies

Biochemical markers and probes are used to research the uptake of compounds by the body. For example, nutritional studies are commonly performed using isotopic labeled compounds.

Brain and kidney function

Studies of brain and kidney function are performed by tracing isotopes throughout these organs for both diagnostics and treatment applications.

Therapeutics

Precursors for therapeutic radioisotopes or radiation therapy are used for a variety of therapies. For example, neuroendocrine tumors are treated by radiotherapy using hormone bound lutetium-177 and yttrium-90.

Clinical pharmacology

Tracing drug metabolism requires the use of isotopes bound to drug in order to understand the processing of the given pharmaceutical by the body.

Research

Biology

A wide range of biochemical processes can be studied using stable isotopes. For example, a technique known as stable isotope labeling by amino acids in cell culture (SILAC) is used in proteomics research to help identify disease biomarkers.

Chemistry

The use of isotope labeling allows chemists to study the mechanisms of chemical reactions, as individual atoms can be followed through a system.

Environmental science

Isotopes are valuable for studying release and spread of pollutants in the environment.

Oceanography

The tracing of isotope movement, either within a local system such as an estuary or on a global scale, can allow study of circulation patterns.

Agriculture

Various compounds labeled with nitrogen-15 are used in the study of processes such as plant metabolism and fertilizer uptake.

Isotope Products

Isotopic metals and compounds are available in a variety of forms and enrichment levels. Compounds include stable isotopes containing carbon, nitrogen, deuterium, noble gases, and metals such as oxides, sulfates, carbonates and more. Additionally, we can produce custom syntheses according to customer needs and specifications for research and development.

Recent Research & Development for Isotopes

  • Elucidating carbon uptake from vinyl chloride using stable isotope probing and Illumina sequencing.. Paes F, Liu X, Mattes TE, Cupples AM.. Appl Microbiol Biotechnol. 2015 May 17.
  • Development and Validation of a Rapid 13C6-Glucose Isotope Dilution UPLC-MRM Mass Spectrometry Method for Use in Determining System Accuracy and Performance of Blood Glucose Monitoring Devices.. Matsunami RK, Angelides K, Engler DA.. J Diabetes Sci Technol. 2015 May 18.
  • Hydrogen and Oxygen Stable Isotope Fractionation in Body Fluid Compartments of Dairy Cattle According to Season, Farm, Breed, and Reproductive Stage.. Abeni F, Petrera F, Capelletti M, Dal Prà A, Bontempo L, Tonon A, Camin F.. PLoS One. 2015 May 21
  • Dual element (15N/ 14N, 13C/ 12C) isotope analysis of glyphosate and AMPA by derivatization-gas chromatography isotope ratio mass spectrometry (GC/IRMS) combined with LC/IRMS.. Mogusu EO, Wolbert JB, Kujawinski DM, Jochmann MA, Elsner M.. Anal Bioanal Chem. 2015 May 13.
  • A 1000-Year Carbon Isotope Rainfall Proxy Record from South African Baobab Trees (Adansonia digitata L.).. Woodborne S, Hall G, Robertson I, Patrut A, Rouault M, Loader NJ, Hofmeyr M.. PLoS One. 2015 May 13
  • Isotope-dilution gas chromatography-mass spectrometry method for the analysis of hydroxyurea.. Garg U, Scott D, Frazee C, Kearns G, Neville K.. Ther Drug Monit. 2015 Jun
  • Utility of stable isotope and COI gene sequencing analysis in inferring origin and authentication of Hairtail fish and Shrimp.. Kim H, Kumar KS, Hwang SY, Kang BC, Moon HB, Shin KH.. J Agric Food Chem. 2015 May 18.
  • Simultaneous quantification of phencynonate and its active metabolite N-demethyl phencynonate in human plasma using liquid chromatography and isotope-dilution mass spectrometry.. Chen Z, Xie H, Liu J, Wang G.. Drug Test Anal. 2015 May 20.
  • Mechanisms of ammonium assimilation by Chlorella vulgaris F1068: Isotope fractionation and proteomic approaches.. Liu N, Li F, Ge F, Tao N, Zhou Q, Wong M.. Bioresour Technol. 2015 Apr 11
  • Weaving a two-dimensional fishing net from titanoniobate nanosheets embedded with Fe3O4 nanocrystals for highly efficient capture and isotope labeling of phosphopeptides. Chen X, Li S, Zhang X, Min Q, Zhu JJ. Nanoscale. 2015 Mar 11.