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A team of researchers from the Institute of Physical Sciences and Mathematics and Information Technologies of the Federal Immanuel Kant Baltic University (BFU) and their colleagues from the Technical University of Gebze have used nuclear magnetic resonance to detect toxic and flammable liquids containing nitrogen. The study was published in Chemical Physics.
Nuclear magnetic resonance (NMR) is the effect of the absorption or emission of energy by a substance that contains nuclei with a non-zero spin in its external magnetic field. The set of resonance lines is individual for each substance and is used for identification. The stronger the magnetic field, the more researchers can determine the structure of the substance. The most intensive NMR signals are observed in the hydrogen nuclei.
Physicists have proposed a new method of detecting explosive and toxic liquids containing nitrogen based on the NMR relaxation method in a weak magnetic field on nitrogen nuclei. 14N. They have also developed a measurement protocol that can be used in security screening procedures. According to scientists, the traditional 1The H NMR method can not be used at a checkpoint because the equipment is too massive and expensive, and the analysis takes too much time. The method based on the study 14NMR relaxometry signals (NMR relaxometry) allow a different technical approach reducing the costs of installation and operation and accelerating the analytical processes. Another advantage of the proposed approach is the analysis of 14N NMR relaxation signals that do not depend on the intermolecular interaction and only slightly depend on the concentration of the substance.
In their work, scientists measured the 14N NMR relaxation time in liquids. They analyzed three groups of substances containing nitrogen: explosive and flammable liquids, compounds with a nitrate group (bound to the nitrogen by three oxygen atoms); and toxic substances with a nitrogen atom not bound to oxygen. As a result, scientists have discovered a range of relaxation time values typical of explosive and toxic substances. This range can be used for their identification.
"In this work we have shown that 14N NMR is an effective method for detecting large quantities of hazardous substances containing nitrogen. We have solved a number of technical problems related to the low resonance frequency and the wide NMR spectrum bands. We have also successfully detected 14N NMR signals of different nitrogen-based substances and obtaining signal relaxation parameters. The majority of toxic and flammable liquids measured in our work are characterized by short relaxation times. This is so that they can be separated from other relatively safe materials. An important advantage of the suggested NMR relaxometry method is the short time required to detect hazardous substances, "says Professor Galina Kupriyanova, author of the study and doctor of physics and mathematics.
According to the researchers, modern portable NMR relaxometry devices are accurate enough to detect hazardous substances at checkpoints.
More information:
G.V. Mozzhukhin et al, Low-field 14N nuclear magnetic resonance for the detection of dangerous liquids, Chemical Physics (2018). DOI: 10.1016 / j.chemphys.2018.07.032
A team of researchers from the Institute of Physical Sciences and Mathematics and Information Technologies of the Federal Immanuel Kant Baltic University (BFU) and their colleagues from the Technical University of Gebze have used nuclear magnetic resonance to detect toxic and flammable liquids containing nitrogen. The study was published in Chemical Physics.
Nuclear magnetic resonance (NMR) is the effect of the absorption or emission of energy by a substance that contains nuclei with a non-zero spin in its external magnetic field. The set of resonance lines is individual for each substance and is used for identification. The stronger the magnetic field, the more researchers can determine the structure of the substance. The most intensive NMR signals are observed in the hydrogen nuclei.
Physicists have proposed a new method of detecting explosive and toxic liquids containing nitrogen based on the NMR relaxation method in a weak magnetic field on nitrogen nuclei. 14N. They have also developed a measurement protocol that can be used in security screening procedures. According to scientists, the traditional 1The H NMR method can not be used at a checkpoint because the equipment is too massive and expensive, and the analysis takes too much time. The method based on the study 14NMR relaxometry signals (NMR relaxometry) allow a different technical approach reducing the costs of installation and operation and accelerating the analytical processes. Another advantage of the proposed approach is the analysis of 14N NMR relaxation signals that do not depend on the intermolecular interaction and only slightly depend on the concentration of the substance.
In their work, scientists measured the 14N NMR relaxation time in liquids. They analyzed three groups of substances containing nitrogen: explosive and flammable liquids, compounds with a nitrate group (bound to the nitrogen by three oxygen atoms); and toxic substances with a nitrogen atom not bound to oxygen. As a result, scientists have discovered a range of relaxation time values typical of explosives and toxic substances. This range can be used for their identification.
"In this work we have shown that 14N NMR is an effective method for detecting large quantities of hazardous substances containing nitrogen. We have solved a number of technical problems related to the low resonance frequency and the wide NMR spectrum bands. We have also successfully detected 14N NMR signals of different nitrogen-based substances and obtaining signal relaxation parameters. The majority of toxic and flammable liquids measured in our work are characterized by short relaxation times. This is so that they can be separated from other relatively safe materials. An important advantage of the suggested NMR relaxometry method is the short time required to detect hazardous substances, "says Professor Galina Kupriyanova, author of the study and doctor of physics and mathematics.
According to the researchers, modern portable NMR relaxometry devices are accurate enough to detect hazardous substances at checkpoints.
More information:
G.V. Mozzhukhin et al, Low-field 14N nuclear magnetic resonance for the detection of dangerous liquids, Chemical Physics (2018). DOI: 10.1016 / j.chemphys.2018.07.032
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