Spectrum reading and processing method and device for multi-sample cell spectral quantitative analysis

Abstract

The invention discloses a spectrum reading and processing method and device of multiple sample cell spectral quantitative analysis. According to the method, sample cells are divided into reference cells and measuring cells; at first, two kinds of sample cells are both filled with a reference substance; then the sample cells are subjected to spectral scanning to obtain spectrums, which take light intensity as the output and are labeled as Back 0, Back 1, Back 2,..., Back N. During the object analysis process, the reference substance in the measuring tanks is replaced by an object to be analyzed; then the spectrums of the measuring tanks and reference cells are scanned in a mode of background spectrum scanning for another time so as to obtain spectrums, which take light intensity as the output and are labeled as meas 0, meas 1, meas 2,..., meas N. Then according to a formula: Absorbi=-log(measi / Backi)+log(meas0 / Back0), the data is processed to obtain a absorption spectrum taking absorbance as the output. The provided method has the advantages that the reference difference between the reference cells and measuring cells can be overcome, especially the influence caused by inconformity of window plate absorption spectrums; the deviation caused by drift and deformation of base line is avoided, and the accuracy of analysis results is largely improved.

Description

【Technical field】 [0001] The invention relates to the field of spectral analysis, in particular to the spectral analysis of the composition and concentration of articles. 【Background technique】 [0002] Spectroscopy can achieve quantitative analysis of almost all polar substances. With the development of computer technology, data analysis and processing technology, in recent years, infrared spectroscopy and ultraviolet spectroscopy have begun to be used in the field of online analysis of gas, liquid, and even solid components and concentrations, but there are still many problems in the current application . Let's take gas analysis as an example to illustrate. [0003] 1) When the spectral resolution is high, it may cause spectral distortion. When the spectral resolution is high and the number of scans is large, the spectral scanning time is longer. For example, a spectral resolution of 1 cm -1 , when the number of scans is 8, the time required to obtain a spectrogram is...

AI Technical Summary

Problems solved by technology

Therefore, in the process of spectral scanning, due to the change of gas concentration, the spectral graph obtained each time is not the average value of the spectral graph under the same gas composition and the same concentration, which makes the obtained spectrum unstable or even distorted, thus making The results of spectral analysis have large deviations, especially in the case of serious overlap of absorption spectra in the gas mixture to be analyzed.

[0004] 2) After the spectrometer has been running for a long time, if the environment changes and the background spectrum needs to be re-scanned, data may be lost

Since the cleaning of the gas chamber takes a long time, generally within a few minutes, the gas to be measured is passed into the gas chamber to stabilize the gas concentration of the measured component, and it also takes several minutes or even longer. Therefore, this method is easy Lead to data loss and poor real-time performance;

[0005] 3) In addition, in applications such as mine gas monitoring, it is necessary to use multiple gas chambers to obtain gas from multiple tunnels. The time before and after gas collection may be long, about several hours, and it is difficult to ensure that the environmental parameters of the instrument are completely accurate before and after gas collection. consistent, including the concentration of carbon dioxide gas in the environment

However, it is very difficult for window coatings, such as KBr coatings in the mid-infrared spectrum, to be exactly the same

Since the absorption spectra of the windows are not exactly the same, this will bring about the absorption spectrum of the gas as figure 1 The baseline shown drifts and even distorts, resulting in large deviations in gas analysis concentrations

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