Sample preparation method used for determining abundance of <15>N isotope of nitrite

Abstract

The invention relates to a sample preparation method used for determining abundance of a <15>N isotope of nitrite. The sample preparation method comprises the following steps: loading a sample, namelyloading a <15>N-labeled to-be-prepared sample and aqueous solution of a reducing agent into a first bulb of a double bulb reaction tube, and loading an acidic material into a second bulb of the double bulb reaction tube; preparing a <15>NO gas, namely maintaining vacuum degree, and adding the acidic material in the second bulb into the first bulb, so that the <15>NO gas is generated; detecting, namely after the vacuum degree of a pipeline between a vacuum plug valve and a gas isotope ratio mass spectrometer is reduced to be below 2*10<-5>Pa, opening the vacuum plug valve, and introducing the<15>NO gas in the first bulb into the gas isotope ratio mass spectrometer; setting detection parameters of the gas isotope ratio mass spectrometer, detecting a relative intensity when mass numbers are30 and 31, and performing a parallel test for multiple times; and calculating an abundance value of the <15>N isotope. Compared with the prior art, the sample preparation method provided by the invention has the advantages that an operation process is safe and reliable, sample pretreatment time is greatly shortened, economic cost is low and test data accuracy and precision are high.

Description

technical field [0001] The present invention relates to a 15 N isotopic abundance detection method, especially related to the determination of nitrite 15 Sample preparation method for N isotopic abundance. Background technique [0002] The increase of reactive nitrogen improves the productivity of the ecosystem in the short term and accumulates more biomass. However, with the rapid increase of nitrogen fertilizer application in farmland, a large part of the reactive nitrogen applied to farmland cannot be completely absorbed and utilized by crops. Instead, it is released into the environment in the form of various reactive nitrogen, which brings serious environmental problems such as eutrophication of surface water, nitrate pollution of groundwater, ozone layer destruction and acid rain, and changes the balance of nitrogen cycle in the global ecosystem. Reducing the anthropogenic emission of reactive nitrogen is a serious challenge for human beings. [0003] An example of ...

AI Technical Summary

Problems solved by technology

[0005] Existing Determination of Nitrite in Samples 15 The method of N isotopic abundance is gas isotopic mass spectrometry, which usually requires the 15 N-labeled nitrite and nitrogen-fixing alloys are transformed into 15 N-labeled ammonia, absorbed by acid 15 N-labeled ammonia gas formation 15 N-labeled ammonium salt solution, concentrated 15 N-labeled ammonium salt solution reacts with sodium hypobromite solution to form 15 N 2 , the gas isotope mass spectrometer is introduced to determine the isotope abundance. This method is also applicable to nitrate and ammonium salt, but this method cannot be applied to the concentration of nitrite in matrix samples. 15 N isotope abundance determination, and when the nitrite content is lower than 3000ppm, the trace amount of nitrogen background in the instrument will affect the 15 The N-labeled nitrogen isotope abundance is diluted, and the test result is low

Images