Superoxygenated Water as an Experimental Sample for NMR Relaxometry

Dakkouri, Marwan; Rauscher, H.; Nestle, Nikolaus

doi:10.1021/ed081p1040

Cited by 3 publications

(1 citation statement)

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“…Dissolved oxygen was not removed from water by nitrogen bubbling or other techniques, even if its presence leads to an increase of the relaxation rates. [31,32] Indeed, the influence of O 2 was considered as rather small when compared with other sources of errors in the measurement of relaxation rates as sample temperature fluctuations. The experiments were performed at three different pHs using different buffers: at pH 2 (KCl/HCl), at pH 3 (NaCl/Glycine/HCl), and at pH 4 (sodium acetate/acetic acid) or (sodium citrate/HCl).…”

Section: Samplementioning

confidence: 99%

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Gossuin

Duez

Blankert

et al. 2023

Magnetic Reson in Chemistry

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The reduction of K 2 Cr 2 O 7 solutions by H 2 O 2 was studied by nuclear magnetic resonance (NMR) relaxometry and UV-vis spectroscopy in HCl/KCl buffer (pH 2), NaCl/glycine/HCl buffer (pH 3), and sodium acetate/acetic acid buffer (pH 4). Because of Cr(III) paramagnetism, 1/T 1 and 1/T 2 of the solutions increase during the reduction of diamagnetic Cr(VI). This increase is proportional to the produced Cr(III) concentration. Using different initial H 2 O 2 concentrations, partially reduced Cr(VI) samples were prepared and studied by T 1 and T 2 relaxometry and by UV-vis spectroscopy. The correlation between the relaxation rates and the concentration of Cr(VI) remaining in the sample, measured by spectroscopy, was excellent. It was possible, thanks to the measure-

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Section: Samplementioning

confidence: 99%

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Gossuin

Duez

Blankert

et al. 2023

Magnetic Reson in Chemistry

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Determination of Phosphorus Content in Cola Drinks by ³¹P NMR Spectroscopy Using External Calibration and Standard Addition Approaches

Kovács,

Sebák,

Szabó

et al. 2024

J. Chem. Educ.

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Both undergraduate and graduate students in chemistry are generally introduced to nuclear magnetic resonance (NMR) spectroscopy as a structure determination tool focusing on 1 H and 13 C measurements. However, NMR has also become an efficient analytical instrument with various applications including routine food analysis and quantitative impurity determination. These quantitation possibilities are rarely encountered in university laboratory practicals, especially in combination with the measurement of other nuclei. In the present paper, we introduce a laboratory practical regarding the determination of the phosphorus content of a cola drink sample using quantitative 31 P NMR ( 31 P qNMR) spectroscopy. Two different calibration approaches are utilized: the external calibration based on dilution series and sequential standard addition. The described experiments have been done by bachelor students in chemistry for more than 10 years and have been part of a bioanalytical chemistry course for biotechnological engineering students for 2 semesters now. Experience has shown that this laboratory practical helps students understand various basic principles of calibration in quantitative instrumental analysis and provides a better understanding of how to run NMR measurements, while data evaluation conveys numerous important concepts. As tested, the practical can also be successfully used in online and distance education.

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Introductory Chemistry: A Molar Relaxivity Experiment in the High School Classroom

et al. 2013

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Dotarem and Magnevist, two clinically available magnetic resonance imaging (MRI) contrast agents, were assessed in a high school science classroom with respect to which is the better contrast agent. Magnevist, the more efficacious contrast agent, has negative side effects because its gadolinium center can escape from its ligand. However, Dotarem, though a less efficacious contrast agent, is a safer drug choice. After the experiment, students are confronted with the FDA warning on Magnevist, which enabled a discussion of drug efficacy versus safety. We describe a laboratory experiment in which NMR spin lattice relaxation rate measurements are used to quantify the relaxivities of the active ingredients of Dotarem and Magnevist. The spin lattice relaxation rate gives the average amount of time it takes the excited nucleus to relax back to the original state. Students learn by constructing molar relaxivity curves based on inversion recovery data sets that Magnevist is more relaxive than Dotarem. This experiment is suitable for any analytical chemistry laboratory with access to NMR.

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Superoxygenated Water as an Experimental Sample for NMR Relaxometry

Cited by 3 publications

References 1 publication

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Determination of Phosphorus Content in Cola Drinks by ³¹P NMR Spectroscopy Using External Calibration and Standard Addition Approaches

Introductory Chemistry: A Molar Relaxivity Experiment in the High School Classroom

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Superoxygenated Water as an Experimental Sample for NMR Relaxometry

Cited by 3 publications

References 1 publication

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Nuclear magnetic resonance relaxometry to monitor chromium (VI) reduction by hydrogen peroxide, ascorbic acid, and aluminum powder

Determination of Phosphorus Content in Cola Drinks by 31P NMR Spectroscopy Using External Calibration and Standard Addition Approaches

Introductory Chemistry: A Molar Relaxivity Experiment in the High School Classroom

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Determination of Phosphorus Content in Cola Drinks by ³¹P NMR Spectroscopy Using External Calibration and Standard Addition Approaches