Abstract: Nitrogen-14 nuclear magnetic resonance (¹⁴N NMR) was introduced as a method of quantitative nitrogen analysis, and applied to the determination of the nitrate content in several humic acids. The result shows that the sensitivity of ¹⁴N NMR detection for small molecules containing nitrogen is relatively high. It is demonstrated that solution ¹⁴N NMR technique can be used in nitrogen analysis for the merits of its convenience without spoilage to the sample and the simultaneous determination of several nitrogen-containing species.

Key words: ¹⁴N NMR, Quantitative determination, Humic acids, Nitrate and Ammonium