A pretreatment method for analysis of nitrate nitrogen and oxygen isotope samples

A technology for oxygen isotope and sample analysis, applied in the preparation of test samples, analytical materials, material separation, etc., can solve the problems of complex operation process, unstable reaction, low conversion efficiency, etc., and achieve low price and easy solid-liquid separation. , a wide range of effects

Active Publication Date: 2021-08-17
成都栢晖生物科技有限公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0017] The purpose of the present invention is to provide a pretreatment method for the analysis of nitrate nitrogen and oxygen isotope samples, which solves the problem that the existing pretreatment methods for the analysis of nitrate nitrogen and oxygen isotope samples have relatively complicated operation process, low conversion efficiency and narrow application range. Unstable reaction, complicated mechanism, etc.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0040] A kind of pretreatment method of nitrate nitrogen oxygen isotope sample analysis described in the present embodiment comprises the following steps:

[0041] Step 1. Sample dilution: Dilute batches of samples separately, each batch includes at least 40 samples, including 3 standards, 2 quality controls, 1 blank and at least 34 actual samples. Specifically, first use 0.2 ~0.7mol / L sodium chloride solution to dilute each sample separately, so that the NO in the sample 3 - -N decreased to 15-25μmol / L, and ensured that the diluted volume of each sample was above 40ml;

[0042] Step 2, pH value adjustment: adjust the pH value of the diluted sample solution to 6.0-8.0, specifically, add a few drops of 0.5-1.0mol / L HCl to reduce the pH value of the solution to 2-3.0, and then add 1.0 ~2.0mol / L imidazole can increase the pH value to 6.0~8.0;

[0043] Step 3, metal reduction: Add reducing metal to the sample solution that has completed the pH value adjustment in step 2. The re...

Embodiment 2

[0048]The traditional method of dilution and pH value adjustment is to first test the initial concentration of the solution, then add the diluent (usually water), then measure the diluted concentration, and then add the diluent, and repeat this many times until the required pH value is obtained. Dilution concentration, or close to the required dilution concentration; in the same way, first measure the initial pH value of the solution, then add the adjustment solution, measure the pH value at this time, then add the adjustment solution, repeat several times, until the desired pH is obtained In the process of diluting and adjusting the pH value, constant oscillation and testing are required. Such artificial efficiency is very low, which seriously affects the progress of the experiment, and even the timeliness of the experiment and the accuracy and reliability of the experimental results. For this reason, on the basis of Example 1, in order to improve the pretreatment efficiency o...

Embodiment 3

[0051] On the basis of Example 2, this embodiment creatively changes the reducing metal in step 3 from copper-plated cadmium grains to iron sheets, and curls the iron sheets into a cylindrical shape. The outer surface of the cylindrical iron sheet The diameter is smaller than the inner diameter of the test tube containing the sample. When the traditional method uses copper-plated cadmium grains as the reduction metal, because the copper-plated cadmium grains are expensive, generally only a few grains (5-10 grains) are used, resulting in a limited contact surface between the copper-plated cadmium grains and the solution, and the reduction reaction is slow and ineffective. However, compared with the traditional copper-plated cadmium particles, the iron sheet of this embodiment has a much larger contact surface with the solution, and the reaction is more sufficient, which can make the NO 3 - more fully reduced to NO 2 - , and the reaction of the iron sheet is more stable than ...

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Abstract

The invention discloses a pretreatment method for the analysis of nitrate nitrogen and oxygen isotope samples, which is characterized in that it comprises the following steps: Step 1, sample dilution: dilute batch samples respectively, and ensure that the diluted volumes of batch samples are all within More than 40ml; step 2, pH value adjustment: adjust the pH value of the diluted sample solution to 6.0-8.0; step 3, metal reduction: add reducing metals to the sample solution whose pH value has been adjusted in step 2 to obtain a solution A, transfer solution A into a headspace vial and seal it with a cap; Step 4, chemical transformation: mix acetic acid solution and NaN 3 Mix the solutions to obtain solution B, then inject solution B into the headspace bottle containing solution A, shake the headspace bottle fully, and transfer the N 2 O gas is sent to a gas mass spectrometer for nitrogen and oxygen isotope ratio determination. The present invention adopts the above method, which can make the operation process relatively simple, improve the conversion efficiency, increase the scope of application, and the reaction is more stable.

Description

technical field [0001] The invention belongs to the field of stable isotope determination, and in particular relates to a pretreatment method for analyzing nitrate nitrogen and oxygen isotope samples. Background technique [0002] Nitrogen is an essential element for life on earth and one of the core elements for life metabolism. In agriculture, nitrogen is both a yield-enhancing factor and a major limiting factor of soil productivity. The development and agricultural application of nitrogen fertilizer industry in the 19th century increased crop yields and played an extremely important role in ensuring food supply and world population growth. However, at the same time, excessive agricultural nitrogen fertilizer input also led to a large amount of active nitrogen entering The environment strongly interferes with the biogeochemical cycle of nitrogen. It is estimated that the amount of reactive nitrogen entering the biosphere due to human activities increased from 15Tg in 186...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): G01N30/02G01N30/72G01N30/88G01N1/38
CPCG01N1/38G01N30/02G01N30/7206G01N30/88G01N2030/025G01N2030/8868
Inventor 李娜周星梅王曦陈建中
Owner 成都栢晖生物科技有限公司
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