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New method for removing water vapor peak interference in infrared spectrum

A technology of infrared spectroscopy and spectroscopy, applied in the field of infrared spectroscopy analysis, to achieve the effect of correcting the lateral deviation of the spectrum, eliminating the water vapor peak, and improving the level of the signal-to-noise ratio

Pending Publication Date: 2022-07-29
宁海德宝立新材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Katsumoto and Ozaki provide a practical moving window algorithm to identify noise spikes caused by water vapor, then discard identified data points corrupted by water vapor, and then employ interpolation techniques to reproduce the discarded data points, in the processed spectra , the water vapor interference is indeed significantly suppressed, but the above method has not been proven to be a reliable means for the second derivative analysis of the bands in the bands where the peaks overlap

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  • New method for removing water vapor peak interference in infrared spectrum
  • New method for removing water vapor peak interference in infrared spectrum
  • New method for removing water vapor peak interference in infrared spectrum

Examples

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Embodiment 1

[0141] In this example, ethanol is taken as the research object, and the ethanol is AR grade, and the infrared absorbance spectrum without water vapor interference is obtained according to the REACT-FILES method of the present invention.

[0142] (1) Obtain the FTIR single-beam spectrum of gas-phase ethanol in the laboratory, such as figure 1 As shown in A, by taking the negative logarithm of the spectral library spectrum and the gas-phase ethanol spectrum according to formula I and taking the first derivative according to formula II, the peak positions are respectively located at 3850 cm according to formula III -1 , 3851cm -1 , 3852cm -1 , 3853cm -1 , 3854cm -1 , 3855cm -1 The phase angle is calculated from the spectral data at , and the two smallest phase angle values ​​are 0.0823゜ and 0.0712゜, which are the two single-beam background spectra selected from the spectral library with the closest peak shift to the sample, respectively as shown in figure 1 shown in 1B and ...

Embodiment 3

[0163] For polyethylene (PE), CH 2 Bending band at 1500cm -1 ~1400cm -1 in the spectral region between. The polyethylene (PE) spectrum obtained using the REACT-FILES method is as follows Image 6 shown, CH 2 The curved band is shown in the rectangular box in the picture, shown in the lower part of the illustration at 1550cm -1 ~1400cm -1 The corresponding second derivative spectrum in the spectral region between, in this case, the interference of moisture can be completely eliminated from the resulting spectrum and the corresponding second derivative spectrum, where the 2D asynchronous correlation spectrum truncated position is 3937.93cm -1 , the polyethylene in the orthorhombic crystal form can be clearly observed in the inset at 1473 cm -1 and 1463cm -1 doublet at , for comparison, the PE at 1550 cm was obtained using conventional methods -1 ~1400cm -1 The second derivative spectrum of the FTIR spectrum between , as shown in the upper part of the inset, it can be s...

Embodiment 4

[0165] In ethylene-vinyl acetate copolymer (EVA), it can be used at 1800cm -1 ~1700cm -1 The carbonyl band of the ester group is observed in the spectral region between. The EVA spectrum obtained using the REACT-FILES method is as follows Figure 7 shown, the carbonyl band of the ester group is shown in the rectangular box in the figure, and the lower part of the inset shows the 1800cm -1 ~1660cm -1 The fine spectral structure of the carbonyl band can be clearly seen in the corresponding second derivative spectra in the spectral region between -1 ; For comparison, EVA at 1800 cm was obtained using conventional methods -1 ~1660cm -1 The second derivative spectrum of the FTIR spectrum between, as shown in the upper part of the inset, shows that the presence of moisture makes it difficult to identify the fine spectral structure of the carbonyl band.

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Abstract

The invention discloses a method for removing water vapor peak interference in an infrared spectrum, and the method specifically comprises the steps: building a spectrum library based on a big data concept and a pigeonhole theory, selecting two single-beam background spectrums closest to single-beam sample spectrum peak position offset from the spectrum library, constructing a two-dimensional asynchronous spectrum of a negative logarithm first-order derivative by using the three spectrums, and calculating the interference of a water vapor peak in the infrared spectrum. The spectrum of the pure substance in the two-dimensional asynchronous spectrum is extracted by cutting off the line at the system peak lacking position of the two-dimensional asynchronous spectrum. According to the method for removing the interference of the water vapor peak in the infrared spectrum, the measurement and effective correction of the spectrum shift between the given single-beam sample spectrum and the single-beam background spectrum are realized, and the interference of water in the gas phase is completely removed through the two-dimensional asynchronous spectrum, so that the high-quality spectrum without the interference of water can be successfully obtained; and a reliable second derivative spectrum. The method disclosed by the invention provides a new thought for researching fine spectral characteristics contained in a spectral region which is seriously interfered and covered by water vapor.

Description

technical field [0001] The invention belongs to the field of infrared spectrum analysis, and particularly relates to a method for removing the interference of water vapor peaks in an infrared spectrum. Background technique [0002] Over the past few decades, FTIR spectroscopy has had significant applications in the physical sciences, chemical and materials research, medical and pharmaceutical practice, and environmental protection. FTIR spectroscopy is a versatile tool for the identification of unknown organic compounds and coordination compounds containing organic ligands. In addition, FTIR spectroscopy can serve as sensitive probes to reflect the structural changes of complex molecular systems in supramolecular assemblies, polymeric materials and biomolecular systems. [0003] In many FTIR experiments, spectra are collected in an environment containing moisture. Absorption peaks caused by atmospheric water molecules in the infrared light path from the source to the detec...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01N21/35G16C10/00G16C20/20G16C20/90
CPCG01N21/35G16C20/20G16C10/00G16C20/90
Inventor 张孝华贺安琪郭然徐怡庄
Owner 宁海德宝立新材料有限公司