Hygroscopic Tendencies of Substances Used as Calibrants for Quantitative Nuclear Magnetic Resonance Spectroscopy

Suiter, Christopher L.; Widegren, Jason A.

doi:10.1021/acs.analchem.1c04268

Cited by 3 publications

(4 citation statements)

References 17 publications

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“…Previous studies have indicated that dimethylsulfone reagents absorb 7.5% moisture after opening a reagent bottle at 22 °C and 100% humidity. 29 Using this coaxial-tube qNMR method, 8.3% hydration was confirmed in dimethylsulfone. Similar hygroscopicity has also been reported for amino acids 30 and pantothenic acids.…”

Section: Tmentioning

confidence: 99%

Coaxial-Tube Quantitative Nuclear Magnetic Resonance for Various Solutions Using SI-Traceable Concentration References

Ogura,

Wakayama

2024

Anal. Chem.

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Quantitative nuclear magnetic resonance (qNMR) is an accepted method for determining analyte concentrations using quantitative substances in one spectrum. Conventional qNMR is performed using a mixture of analytes and reference substances. In coaxial-tube NMR, two tubes are used as different solutions, similar to normal NMR spectra. Currently, coaxial tubes with various diameters are available; however, coaxial-tube qNMR is limited, and a general analytical protocol is yet to be proposed. In this study, we established an effective volume ratio (EVR) measurement method using the weight density and qNMR methods. Various analyte concentrations were determined using coaxial-tube qNMR and an SI-traceable reagent. The EVR required for the qNMR concentration calculation was determined using a coefficient of variation (CV) of <1% for an inner tube of ϕ 3 mm or less. The peak integral of each substance was correlated with the effective volume, depending on the abundance of the tube and matched 1 H in the solution. The T 1 relaxation times differed depending on the substructure, and the T 1 values of the formate and OH groups varied for each tube set. Thus, each partial structural characteristic of the peak must be understood before qNMR is performed. The concentrations of various substances, including hygroscopic substances, were determined using coaxial-tube qNMR. Coaxial tubes eliminate the need to mix the analyte with the reference substance; thus, we can quantify the analyte without causing pH and structural changes caused by other mixtures and reuse the analyte for other test systems.

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Section: Tmentioning

confidence: 99%

Coaxial-Tube Quantitative Nuclear Magnetic Resonance for Various Solutions Using SI-Traceable Concentration References

Ogura,

Wakayama

2024

Anal. Chem.

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“…6 However, the presence of moisture in DMS and other reference materials represents a problem that can make their quantitative determinations less accurate. 7 Water represents the only material whose purity is not affected by the presence of moisture. It is also readily available.…”

Section: Introductionmentioning

confidence: 99%

“…Dimethyl sulfone (DMS) has been proposed as the universal reference material 6 . However, the presence of moisture in DMS and other reference materials represents a problem that can make their quantitative determinations less accurate 7 …”

Section: Introductionmentioning

confidence: 99%

Quantitative NMR using water as internal calibrant

Xiang

2023

Magnetic Reson in Chemistry

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A new quantitative nuclear magnetic resonance (qNMR) method, called qNMRw, using water as the internal calibrant has been developed. Its principles, procedures, calculations, and test results are presented here. It is shown to avoid the difficulties created by moisture present in other reference materials. High precision and accuracy can be achieved with qNMRw. The method can be used for analyzing technical materials, herbicide formulation products, and other types of chemical samples. It can also be used to measure the purity and concentration of materials to be used as quantitation calibrants.

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“…Around thirty related articles were referenced as an indication of the usefulness of the constant-current coulometry. In the last six years, some articles based on the use of coulometry, from the analytical point of view, were published describing the application to the detection and quantification of a variety of compounds from metals, pharmaceuticals, water, antioxidants, gases, and certified materials [ 9 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 ]. Furthermore, numerous papers on coulometry have been published in education journals due to their instructional character (see recent papers on coulometry for chemical education [ 19 , 20 , 21 ] and the references therein).…”

Section: Introductionmentioning

confidence: 99%

Coulometer from a Digitally Controlled Galvanostat with Photometric Endpoint Detection

González-Arjona

González

López-Pérez

et al. 2022

Sensors

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In this work, a coulometer was developed from a digitally controlled galvanostat. A simple colorimeter based on a RGB LED was used as a light emitter coupled to light detectors, while light dependent resistance (LDR) and photodiodes have been developed as endpoint detectors. Both hardware and software have been adapted from the original galvanostat design. Regarding the hardware, new electrical signal conditioners (filters and voltage dividers) were included to optimize the working system. The software was developed based on an open source Arduino UNO microcontroller. The different variables that control the titration process are managed by an add-in module for Excel data acquisition software that is freely available. A study of the possible variables that influence the titration process has been carried out. The system was tested with two classical coulometric titrations such as iodometry (thiosulfate, ascorbic acid) and acid/base (potassium acid phthalate as standard). The developed system is versatile as different endpoint color indicators can be employed (starch and phenolphthalein for the investigated reactions). Different experimental arrangements have been studied: the nature of the electrodes (Pt, Ag), type of cells (two separate compartments or a single compartment), and light detectors (LDR, photodiode). The influence of several experimental parameters (both electrical, light, and integration time) was studied and chosen to obtain the best performance of the complete system. Reproducibility results below 1% can be obtained under controlled conditions. In the case of acid/base titrations, the presence of atmospheric carbon dioxide was detected, whose interference was mainly affected by the stirring rate and the titration time.

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Hygroscopic Tendencies of Substances Used as Calibrants for Quantitative Nuclear Magnetic Resonance Spectroscopy

Cited by 3 publications

References 17 publications

Coaxial-Tube Quantitative Nuclear Magnetic Resonance for Various Solutions Using SI-Traceable Concentration References

Coaxial-Tube Quantitative Nuclear Magnetic Resonance for Various Solutions Using SI-Traceable Concentration References

Quantitative NMR using water as internal calibrant

Coulometer from a Digitally Controlled Galvanostat with Photometric Endpoint Detection

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