A study on the simultaneous determination of nitrogen content and 15N isotope abundance in plants using peak height intensities at m/z 28 and 29

Long Xie; Yameng Zhao; Chuyao Wang; Sen Xu; Ruoning Fan; Huimin Gao; Jinlan Xu; Shenghao Zhu; Wen Lei; Sheng Han

doi:10.1016/j.talanta.2024.126078

A study on the simultaneous determination of nitrogen content and ¹⁵N isotope abundance in plants using peak height intensities at m/z 28 and 29

Talanta. 2024 Apr 16:275:126078. doi: 10.1016/j.talanta.2024.126078. Online ahead of print.

Authors

Long Xie¹, Yameng Zhao², Chuyao Wang², Sen Xu², Ruoning Fan², Huimin Gao², Jinlan Xu², Shenghao Zhu³, Wen Lei⁴, Sheng Han⁵

Affiliations

¹ School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 201418, China; Shanghai Research Institute of Chemical Industry Co., Ltd., Shanghai Stable Isotope Testing and Reagent Professional Technical Service Platform, Shanghai, 200062, China.
² Shanghai Research Institute of Chemical Industry Co., Ltd., Shanghai Stable Isotope Testing and Reagent Professional Technical Service Platform, Shanghai, 200062, China.
³ Shanghai Research Institute of Chemical Industry Co., Ltd., Shanghai Stable Isotope Testing and Reagent Professional Technical Service Platform, Shanghai, 200062, China; School of Chemistry and Molecular Engineering, East China University of Science and Technology, Shanghai, 200237, China.
⁴ Shanghai Research Institute of Chemical Industry Co., Ltd., Shanghai Stable Isotope Testing and Reagent Professional Technical Service Platform, Shanghai, 200062, China. Electronic address: leiwensrici@163.com.
⁵ School of Chemical and Environmental Engineering, Shanghai Institute of Technology, Shanghai, 201418, China. Electronic address: hansheng654321@sina.com.

PMID: 38678921
DOI: 10.1016/j.talanta.2024.126078

Abstract

A method for simultaneous determination of nitrogen content and ¹⁵N isotope abundance in plants was established by Elemental analysis-gas isotope ratio mass spectrometry. Taking poplar leaves and l-glutamic acid as standards, nitrogen content was determined using the standard curve established by weighted least squares regression between the mass of nitrogen element and the total peak height intensity at m/z 28 and 29. Then the ¹⁵N isotope abundance was calculated with the peak height intensity at m/z 28 and 29. Through the comparison of several sets of experiments, the impact of mass discrimination effect, tin capsule consumables, isotope memory effect, and the quality of nitrogen on the results were assessed. The results showed that with a weight of 1/x², the standard curve has a coefficient of determination (R²) of 0.9996. Compared to the traditional Kjeldahl method, the measured nitrogen content deviated less than 0.2 %, and the standard deviation (SD) was less than 0.2 %. Compared to the sodium hypobromite method, the ¹⁵N isotopic abundances differed less than 0.2 atom%¹⁵N, and the SD was less than 0.2 atom% ¹⁵N. The established method offers the advantages of being fast, simple, accurate, and high throughput, providing a novel approach for the simultaneous determination of nitrogen content and ¹⁵N isotope abundance in plant samples.

Keywords: (15)N isotope abundance; Elemental analysis-gas isotope ratio mass spectrometry; Nitrogen content; Plants; Weighted least squares.