関連する実験動画

Updated: Jun 29, 2026

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging
11:43

Hyperpolarized 13C Metabolic Magnetic Resonance Spectroscopy and Imaging

Published on: December 30, 2016

炭素13 / 炭素12の比率は,ハニーの中で比較的均一です

L W Doner, J W White

    Science (New York, N.Y.)
    |August 26, 1977
    PubMed
    まとめ

    蜂蜜の炭素13と炭素12の同位体比は最小の変動を示しており,高果糖トウモロコシシロップによる偽造を検出するための信頼できる指標となっています. この発見は,C3植物から得られた蜂蜜の真偽を裏付けるものである.

    さらに関連する動画

    Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers11:14

    Fatty Acid 13C Isotopologue Profiling Provides Insight into Trophic Carbon Transfer and Lipid Metabolism of Invertebrate Consumers

    Published on: April 17, 2018

    Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis07:57

    Sampling and Pretreatment of Tooth Enamel Carbonate for Stable Carbon and Oxygen Isotope Analysis

    Published on: August 15, 2018

    関連する概念動画

    Isotopes01:12

    Isotopes

    Elements have a set number of protons that determines their atomic number (Z). For example, all atoms with eight protons are oxygen; however, the number of neutrons can vary for atoms of the same element. The sum of the number of protons and the number of neutrons is the mass number (A). Atoms with the same atomic number but different mass numbers are called isotopes. Elements can have multiple isotopes, for example, carbon-12, carbon-13, and carbon-14.An element's atomic mass, or weight, is a...
    Carbon-13 (¹³C) NMR: Overview01:10

    Carbon-13 (¹³C) NMR: Overview

    Carbon-13 is a naturally occurring NMR-active isotope of carbon with a low natural abundance of 1.1%. In contrast, carbon-12 is the most abundant isotope of carbon with zero nuclear spin. Therefore, it is NMR inactive. The gyromagnetic ratio of carbon-13 is smaller than that of protons. As a result, carbon-13 resonance is about 6000 times weaker than proton resonance. For a given magnetic field strength, the resonance frequency of carbon-13 is about one-fourth of the resonance frequency for...
    ¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)01:20

    ¹³C NMR: Distortionless Enhancement by Polarization Transfer (DEPT)

    When proton-coupled carbon-13 spectra are simplified by a broadband proton decoupling technique, structural information about the coupled protons is lost. Distortionless enhancement by polarization transfer (DEPT) is a technique that provides information on the number of hydrogens attached to each carbon in a molecule. While the DEPT experiment utilizes complex pulse sequences, the pulse delay and flip angle are specifically manipulated. The resulting signals have different phases depending on...
    High-Resolution Mass Spectrometry (HRMS)01:15

    High-Resolution Mass Spectrometry (HRMS)

    The resolution of a mass spectrometer depends on the efficiency of separating ions with different ion masses. The mass of an atom is approximated to the sum of the masses of protons and neutrons inside, considering the masses of protons and neutrons as equal. However, the masses of the proton (1.6726 × 10−24 g) and neutron (1.6749 × 10−24 g) are not truly equal. There is a minor error in the expression of atomic masses relative to the simplest atom of hydrogen. For example, the mass of helium...
    ¹³C NMR: ¹H–¹³C Decoupling01:04

    ¹³C NMR: ¹H–¹³C Decoupling

    The probability of having two carbon-13 atoms next to each other is negligible because of the low natural abundance of carbon-13. Consequently, peak splitting due to carbon-carbon spin-spin coupling is not observed in spectra. However, protons up to three sigma bonds away split the carbon signal according to the n+1 rule, resulting in complicated spectra.
    A broadband decoupling technique is used to simplify these complex, sometimes overlapping, signals. Broadband decoupling relies on a...
    Mass Spectrometry: Isotope Effect01:13

    Mass Spectrometry: Isotope Effect

    Most elements exist in nature as a mixture of isotopes. The isotopes differ in weight due to their respective number of neutrons. The molecular weight of a molecule is different depending on the specific isotope of its elements involved. As a result, the mass spectrum of the molecule exhibits peaks from the same fragment at multiple positions. The positions of these mass signals depend on the mass differences between isotopes. Furthermore, the intensity of these signals is dependent on the...