δ¹⁵N Values of Wheat Plant Analysis by Istope Ratio Mass Spectrometry

A method is established for the determination of the δ¹⁵N values of stable isotope ¹⁵N-labeled wheat plants by the element analyzer-isotope ratio mass spectrometic(EA-IRMS) technology. The stability and linearity of the EA-IRMS system were tested. The results showed that the standard deviation of stability was 0.03‰ of standard N₂. When the intensity of isotopic signal ranged from 1e^-9 to 1e^-8A, the linearity of EA-IRMS system was 0.009‰/nA. 4 mg is the best sample quantity for standard wheat flour (OAS/Isotope) because the standard deviation of δ¹⁵N values was the smallest. The precision and accuracy of the results for the standard ammonium sulfate (IAEA-N₂-6), standard wheat flour and the ¹³N-labeled wheat samples were analyzed and all the standard deviations of δ¹⁵N values were less than 5%. The method is rapid and accuracy for the determination of the δ¹⁵N values of stable isotope ¹⁵N-labeled wheat samples, it provides effective technical ways for the study of nitrogen translocation and use efficiency of wheat plant.