Measurement real-time correction method of carbon dioxide isotope abundance value

Abstract

The invention discloses a measurement real-time correction method of a carbon dioxide isotope abundance value. The method comprises the following steps: (1) collecting reference gas and sample gas; (2) connecting the collected reference gas and the collected sample gas to a group of detection passages of a test instrument; (3) measuring a concentration value of original 12C carbon dioxide gas, a concentration value of original 13C carbon dioxide gas and an isotope abundance DEL2 of the sample gas by using a zero gas clearing detection gas path; (4) measuring a concentration value of original 12C carbon dioxide gas, a concentration value of original 13C carbon dioxide gas and an isotope abundance DEL1 of the reference gas by using the zero gas clearing detection gas path; (5) comparing the concentration values of the two original 12C carbon dioxide gas, and calculating a concentration difference D of the two original 12C carbon dioxide gas; and (6) comparing an absolute value of the concentration difference with a set threshold value, if the absolute value of the concentration difference is not greater than the threshold value, directly calculating an isotope abundance difference of the reference gas and the sample gas, and obtaining DOB equal to subtracting DEL1 from DEL2.

Description

technical field [0001] The invention relates to a real-time correction method, in particular to a real-time correction method for measuring the carbon dioxide isotope abundance value. Background technique [0002] The isotopic abundance value refers to the ratio of the number of atoms of a specific isotope to the total number of atoms of the element in an isotope mixture of an element. Since the relative abundance of light isotopes is very high and that of heavy isotopes is very low in nature, the δ value of the sample is used to represent the isotopic composition of the sample in actual work. The ratio (Rsq) of an isotope is compared with the isotope ratio (Rst) of a standard substance, which is called the δ value of the sample (that is, the DEL value), which is defined as: δ(‰)=(Rsq / Rst-1)×1000. Therefore, in order to measure a gas containing 13 The abundance value of carbon dioxide gas of C isotope must be measured separately 13 C carbon dioxide gas and 12 C The conc...

AI Technical Summary

Problems solved by technology

Using this method, on the one hand, due to the limited data points collected, there will be a certain deviation between the fitted correction value and the actual required correction value, resulting in a deviation between the final result and the actual measured value.

On the other hand, since the calibration curve of the instrument will drift with the change of temperature and pressure, this requires the operator of the instrument to calibrate the instrument regularly

This kind of calibration work is usually done once a week, and some instruments even need to be calibrated once a day after starting up. Each calibration takes about ten minutes, which increases the workload of the operator.

In addition, when the external environment changes drastically, if the operator fails to calibrate the instrument in time, it will affect the accuracy of the measurement results.

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