Assafiri Aya, Jia Chen, Thomas Donald S, Hibbert David B, Zhao Chuan
School of Chemistry, University of New South Wales, Sydney, 2052, Australia.
NMR Facility, Mark Wainwright Analytical Center, University of New South Wales, Sydney, 2052, Australia.
Small Methods. 2024 Aug;8(8):e2301373. doi: 10.1002/smtd.202301373. Epub 2024 Feb 14.
A facile NMR method is reported for analysis of ammonia from the electrochemical reduction of nitrogen, which compares a calibrated colorimetric method, a calibrated H NMR method and two H NMR direct measurements using external reference materials. Unlike spectrophotometric methods, H NMR requires less bench time and does not require separation of ammonia from the electrolyte. A novel approach to the problem of radiation damping in NMR measurements considered the specific role of hardware tuning. Radiation damping is suppressed improving signal-to-noise ratio and detection limit (1.5 µg L). The method is demonstrated to be effective for the analysis of ammonia from direct electrochemical nitrogen reduction in KOH, and from lithium-mediated nitrogen reduction in a non-aqueous solution. An uncertainty budget is prepared for the measurement of ammonia.
报道了一种用于分析氮电化学还原产生的氨的简便核磁共振（NMR）方法，该方法将校准的比色法、校准的氢核磁共振方法以及使用外部参考材料的两种氢核磁共振直接测量方法进行了比较。与分光光度法不同，氢核磁共振所需的实验台时间更少，并且不需要将氨与电解质分离。一种解决核磁共振测量中辐射阻尼问题的新方法考虑了硬件调谐的特定作用。通过抑制辐射阻尼提高了信噪比和检测限（1.5μg/L）。该方法被证明对于分析氢氧化钾中直接电化学氮还原产生的氨以及非水溶液中锂介导的氮还原产生的氨是有效的。还编制了氨测量的不确定度预算。
