Refining Universal Procedures for Ammonium Quantification via Rapid 1H NMR Analysis for Dinitrogen Reduction Studies

Refining Universal Procedures for Ammonium Quantification via Rapid 1H NMR Analysis for Dinitrogen Reduction Studies Full article

Journal

ACS Energy Letters
ISSN: 2380-8195

Output data

Year: 2020, Volume: 5, Number: 3, Pages: 736-741 Pages count : 6 DOI: 10.1021/acsenergylett.9b02812

Authors

Hodgetts Rebecca Y. ¹ , Kiryutin Alexey S. ^2,3 , Nichols Peter ⁴ , Du Hoang-Long ¹ , Bakker Jacinta M. ⁴ , Macfarlane Douglas R. ¹ , Simonov Alexandr N. ¹

Affiliations

1	School of Chemistry and the ARC Centre of Excellence for Electromaterials Science, Monash University, Victoria 3800, Australia
2	International Tomography Center SB RAS, Institutskaya str. 3a, Novosibirsk 630090, Russia
3	Novosibirsk State University, Pirogova str. 1, Novosibirsk 630090, Russia
4	School of Chemistry, Monash University, Victoria 3800, Australia

As research on sustainable ammonia synthesis via electrochemical and photochemical N2 reduction progresses to include a wider variety of aqueous and aprotic electrolytes, 1H NMR spectroscopy is increasingly adopted as a means for ammonium quantification. However, this method is highly sensitive to experimental parameters, as demonstrated herein using a highly versatile and robust NMR pulse program. We demonstrate the sensitivity of the measurement to the final pH of the analyzed solution and identify a [H+] concentration range enabling robust quantification. We compare direct quantification versus calibration approaches to show that the former is highly sensitive to spin relaxation effects and identify the latter as the most reliable approach. This method, when optimized, enables direct, rapid quantification of both 14NH4+ and 15NH4+ within 12–22 min. The limit of detection of 5–10 μM, depending on the solvent, which meets the needs of current electrochemical and photochemical N2 reduction research.

Hodgetts R.Y. , Kiryutin A.S. , Nichols P. , Du H-L. , Bakker J.M. , Macfarlane D.R. , Simonov A.N.
Refining Universal Procedures for Ammonium Quantification via Rapid 1H NMR Analysis for Dinitrogen Reduction Studies
ACS Energy Letters. 2020. V.5. N3. P.736-741. DOI: 10.1021/acsenergylett.9b02812 WOS OpenAlex

Submitted:	Dec 24, 2019
Accepted:	Feb 4, 2020
Published print:	Feb 4, 2020
Published online:	Mar 13, 2020

Web of science:	WOS:000526311000006
OpenAlex:	W3004926049

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