Low-content carbon and nitrogen sample isotope dual-channel test device

Abstract

The present invention discloses a device for double channel test of low carbon and nitrogen content sample isotope. The device is as below: adding soil or plant samples to 10 separate oxidation furnaces combined by two sets of oxidation furnaces and sealing; opening switch control solenoid valves corresponding to each oxidation furnace and corresponding solenoid valves on a connecting pipeline; first extracting air in each oxidation tube by a dry pump, maintaining the vacuum at 3*10<-3>mbar; then extracting each oxidation tube by a molecular pump to vacuum of 2*10<-6>mbar; then heating the oxidation tubes to 960 DEG C, filling oxygen to each oxidation tube to completely oxidize samples in the oxidation tubes and to generate carbon and nitrogen oxides and water; sending mixed gas to a reduction furnace to generate N2, CO2 and H2O; then removing water and enriching to collect N2, CO2, H2O in cold traps respectively; and finally gradually releasing gas in the cold traps to a sample gas reservoir B1 in a double-channel injector system, while sending standard reference gas provided by a G3 or G4 into a standard reference gas reservoir B1 of the dual injector system, and starting double channel program detection.

Description

technical field [0001] The invention relates to a device for isotope testing of low-content carbon and nitrogen samples using a dual-path testing method. Background technique [0002] With the rise of stable isotope ecology, scientists have paid more and more attention to the research on the water-carbon-nitrogen coupling cycle of the ecosystem, especially in the study of organic carbon and nitrogen in soil, plants, fish, bird feathers, etc., which have involved From climate change and ecological effects, water and nutrient competition among different species, bird migration, fish food chain and many other fields. [0003] At present, the FLASH 2000 organic element analyzer from Thermo Fisher Scientific is commonly used in the domestic and foreign markets, which is connected with a gas stable isotope mass spectrometer (MAT-253) to complete the analysis and determination of organic carbon and nitrogen isotopes. There are excellent applications in gas path control and connect...

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Problems solved by technology

[0003] At present, the FLASH 2000 organic element analyzer from Thermo Fisher Scientific is commonly used in the domestic and foreign markets, which is connected with a gas stable isotope mass spectrometer (MAT-253) to complete the analysis and determination of organic carbon and nitrogen isotopes. There are excellent applications in gas path control and connection, data processing, etc., but it is not ideal for samples with low nitrogen content such as soil, loess, lakes and other sediment tests, because the sample volume required to test low-content carbon and nitrogen samples is very small. Large (generally >50mg), but too much sample volume will cause problems such as insufficient combustion and reduced oxidation capacity caused by the accumulation effect of the sample; in addition, the above connection uses a continuous flow sample injection method, although it is fast, each sample test ends After that, the test cannot be repeated, and the only way to make up for the test errors caused by misoperation or other reasons is to re-add the sample test

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