Method for identifying stable carbon isotope composition of isoprene in atmosphere

Abstract

The invention discloses a method for determining stable carbon isotope composition of isoprene in atmosphere, comprising the following steps: step I: determining the stable carbon isotope composition of 2-methyl butantetraol in aerosol; step B: determining an isotopic fractionation constant of 2-methyl butantetraol generated by isoprene through photochemical reaction; and step C: calculating the stable carbon isotope composition of the isoprene in the atmosphere. The method can be used for analyzing a source of the isoprene in the atmosphere, discussing a migration and transfer rule, and researching and exploring distribution of vegetations (C3, C4 and CAM) with different photosynthesis types in an environment. The method solves the difficult problem that the stable carbon isotope composition of the active volatile organic compound in the atmosphere is hard to determine accurately and establishes a method foundation for explaining generation, migration, transfer and trend rules of the isoprene in nature.

Description

technical field [0001] The invention relates to a method for identifying the stable carbon isotope composition of atmospheric isoprene, which belongs to the technical field of environmental monitoring. Background technique [0002] Isoprene is an important non-methane hydrocarbon in the ambient atmosphere, it is easy to combine with OH·, O 3 , NOx·reaction, is an important precursor of ozone generation, thus affecting the oxidation characteristics of the atmosphere. 2-Methylbutanetetraol is a molecular marker for atmospheric photooxidation of isoprene. This study intends to use the stable carbon isotope analysis method of methylboronic acid derivatives to determine the δ of 2-methylbutanitol in different environmental aerosols 13 Composition of C, according to δ of 2-methylbutanetetraol 13 C information further explores the delta of its precursor isoprene 13 C composition, this method can be used to apportion the source of atmospheric isoprene in different regions and ex...

AI Technical Summary

Problems solved by technology

[0008] Directly measure the stable carbon isotope composition of atmospheric isoprene, so as to judge its source and degradation path, there are three bottleneck problems to be solved: first, the residence time of isoprene in the atmosphere is limited, and the reaction speed is very fast. In the limited transmission time, the transmission distance is also limited. Therefore, the isoprene measured by the test must be the isoprene produced in a certain range, and it is impossible to judge the main content of isoprene in this area from a large area. source composition; the second is isoprene since it enters the atmosphere and its isotopic composition changes continuously during its transport process, δ 13 The change of C value will make it impossible to make a more accurate inference of its source; the third is that the determination of atmospheric isoprene isotope composition requires expensive low-temperature pre-concentration sampling equipment, and the method is difficult

Many of the reasons above limit the application of the technology of directly identifying the source of isoprene through monomer carbon isotope technology to a considerable extent.

Images