Determination of Carbon and Nitrogen Isotope Fractions in Asparagine, Aspartic Acid, Threonine and Methionine

The nomenclature for compounds that are modified with isotopes is growing every day. Compounds can be modified with isotopes either individually, in a functional group or groups, or completely with all atomic centers of the element. This diversity of isotope-modified compounds increases the range of researches that can be studied using them. Compounds modified with isotopes of carbon-13 or nitrogen-15 can be converted into carbon monoxide, carbon dioxide and molecular nitrogen. Currently, only the average value of carbon-13 or nitrogen-15 isotopes can be determined. However, by directly determining the atomic share of these isotopes in organic compounds modified with isotopes, information about the isotopic centers of the element can be obtained. The atomic fraction of an element is defined as a single carbon or nitrogen isotope-modified center or centers, or all centers that are isotope-modified with that element at the same time. Carbon-13 or nitrogen-15 isotopes’ atomic fraction can be determined molecularly or with fragment ions of different elemental content, or both. This makes the method self-verifying, increasing the accuracy and reliability of the results obtained. Amino acids, such as asparagine, aspartic acid, methionine, and threonine, are essential for the human body. This proposed method of isotopic analysis will increase the possibilities for scientific research using these compounds.