Raman spectrum based substance qualitative detection method

Abstract

The invention discloses a Raman spectrum based substance qualitative detection method, and relates to a substance qualitative detection method. The method comprises the following steps of S1, establishing a Raman normalized second-order spectrum library of a standard substance; S2, acquiring a mask threshold; S3, respectively establishing a spectrogram mask for each standard substance according to the Raman normalized second-order spectrum library of the standard substance and the mask threshold; and S4, judging the composition of the to-be-detected substance according to the spectrogram mask of the standard substance. The qualitative Raman spectrum library is established by using the spectrum second derivative-mask technology, the interference of fluorescence on judgement is eliminated through the processing of a second derivative, and the problem of Raman qualitativeness under the high fluorescence background is solved; and besides, the second derivative can effectively reduce the width of the characteristic peak, and the identification accuracy is improved. Database management and retrieval based on the spectrum second derivative-mask technology are more accurate, and the retrieval efficiency of the spectrum library is effectively improved.

Description

technical field [0001] The invention relates to a qualitative detection method for substances, in particular to a qualitative detection method for substances based on Raman spectroscopy. Background technique [0002] Raman spectroscopy can reflect the vibration and rotation information of the molecular skeleton, and is an effective qualitative method for substances. In recent years, as the cost of the instrument has dropped, its application is gradually becoming popular. However, Raman signal excitation also excites fluorescence at the same time, and the fluorescence intensity is usually several orders of magnitude higher than the Raman signal, causing great interference to the qualitative, which has always been a key problem that plagues the application of Raman spectroscopy. The current commonly used method is to eliminate or reduce fluorescence as much as possible, but the actual sample situation is usually unpredictable, and it is often difficult to control even if long...

AI Technical Summary

Problems solved by technology

However, Raman signal excitation also excites fluorescence at the same time, and the fluorescence intensity is usually several orders of magnitude higher than the Raman signal, causing great interference to the qualitative, which has always been a key problem that plagues the application of Raman spectroscopy.

At present, the commonly used method is to eliminate or reduce the fluorescence as much as possible, but the actual sample situation is usually unpredictable, and it is often difficult to control even if a longer excitation wavelength is used.

The patent application with the publication number CN 105223184 A discloses a "Raman spectrometer-based substance qualitative and component quantitative detection method", which has the following disadvantages: for strong fluorescence interference, it will lead to characteristic peak ratio errors Large, breaking through its set threshold; for multi-component mixing, similar situations may also occur, so the invention points out that it can only deal with "mixtures of two known samples mixed in different proportions"

[0003] The patent application with the publication number CN 101285773A discloses a "Raman Spectroscopy Qualitative Detection Method for Blended Fabric Components", which also has the following disadvantages: for samples containing fluorescence interference, this method needs to be used as a baseline by means of Correction, and the problem caused by baseline correction is spectral line distortion, so the patent also pointed out that it can only "judge the known sample that is closest to the component of the sample to be tested"

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