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Accelerating ¹H NMR Detection of Aqueous Ammonia.

ABSTRACT: Direct electrolytic N₂ reduction to ammonia (NH₃) is a renewable alternative to the Haber-Bosch process. The activity and selectivity of electrocatalysts are evaluated by measuring the amount of NH₃ in the electrolyte. Quantitative ¹H nuclear magnetic resonance (qNMR) detection reduces the bench time to analyze samples of NH₃ (present in the assay as NH₄ ⁺) compared to conventional spectrophotometric methods. However, many groups do not have access to an NMR spectrometer with sufficiently high sensitivity. We report that by adding 1 mM paramagnetic Gd³⁺ ions to the NMR sample, the required analysis time can be reduced by an order of magnitude such that fast NH₄ ⁺ detection becomes accessible with a standard NMR spectrometer. Accurate, internally calibrated quantification is possible over a wide pH range.

SUBMITTER: Kolen M

PROVIDER: S-EPMC7931439 | biostudies-literature | 2021 Mar

REPOSITORIES: biostudies-literature

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Accelerating 1H NMR Detection of Aqueous Ammonia.

Kolen Martin M Smith Wilson A WA Mulder Fokko M FM

ACS omega 20210219 8

Direct electrolytic N2 reduction to ammonia (NH3) is a renewable alternative to the Haber-Bosch process. The activity and selectivity of electrocatalysts are evaluated by measuring the amount of NH3 in the electrolyte. Quantitative 1H nuclear magnetic resonance (qNMR) detection reduces the bench time to analyze samples of NH3 (present in the assay as NH4 +) compared to conventional spectrophotometric methods. However, m ...[more]

PMID: 33681609

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