A method for analyzing the residual amount of bone glue in the sealing material of murals and cultural relics

Abstract

The invention discloses an analysis method for the residual amount of bone glue used as a mural cultural relic sealing material, which relates to the technical field of analytical chemistry and specifically comprises the following steps: S1: sample preparation: preparing finished bone glue, simulated mural sample blocks, and mural fragments; S2: Fourier transform infrared spectroscopy scanning and spectrum processing of the three samples; S3: near-infrared spectroscopy analysis of the finished bone glue; S4: gas chromatography-mass spectrometry analysis of the finished bone glue and the mural fragments. The method of the invention has the advantages of high extraction efficiency, good recovery rate, and high sensitivity.

Description

Technical Field

[0001] The invention relates to the technical field of analytical chemistry, and in particular to a method for analyzing the residual amount of bone glue in a mural cultural relic sealing material. Background Art

[0002] In the process of cultural relic protection and mural protection, the murals need to be peeled off for protection due to the limitations of the preservation environment. During the rescue peeling and protection, the mural pigment layer must first be reinforced, then the picture is sealed, and finally the sealing material is used to further enhance the overall strength of the mural. According to investigations, the surface sealing materials of the murals in the collection have been used in the removal of tomb murals since the 1950s. They generally include natural glues such as bone glue, leather glue, peach glue, and high molecular materials such as polyvinyl acetate emulsion, trimethyl resin, and polyethanol butyral. At present, bone glue is widely used.

[0003] After the murals are removed, the bone glue needs to be removed. Whether the bone glue is completely removed affects the subsequent work of mural restoration. The residual bone glue sealing material will also cause secondary damage to the pigment of the mural itself after aging. These problems have hindered the restoration of cultural relics, making some murals unrepaired for many years. Therefore, the analysis and determination of the residual bone glue on the murals that have been removed using bone glue as a sealing material is very important for the restoration of murals.

[0004] The main component of bone glue is protein. At present, the residual amount of bone glue is mainly determined by qualitative and quantitative analysis of the amino acids decomposed after the digestion of bone glue. The analysis of the residual amount helps to select the remover and quantify the residual situation. However, most of the analytical methods in the prior art have problems such as low extraction efficiency and detection sensitivity. Based on this, developing a fast, simple and accurate bone glue detection method, and quickly and accurately analyzing the residual amount of bone glue after removing the sealing material from mural cultural relics is a technical problem that people in the field need to solve urgently. Summary of the invention

[0005] In view of the above problems, the present invention provides an analysis method for the residual amount of bone glue in mural cultural relic sealing materials, which solves the problems of low extraction efficiency and detection sensitivity of the analysis method for the residual amount of bone glue in mural cultural relic sealing materials in the prior art.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides a method for analyzing the residual amount of bone glue in mural cultural relics sealing materials, which specifically comprises the following steps:

[0008] S1: Sample preparation: prepare finished bone glue, simulated mural samples, and mural fragments;

[0009] S2: Fourier transform infrared spectra scanning and spectrum processing of three samples;

[0010] S3: Near infrared spectroscopy analysis of finished bone glue;

[0011] S4: GC-MS analysis of finished bone glue and mural fragments.

[0012] Furthermore, in step S2, the Fourier transform infrared spectrum scanning and spectrum graph processing of the three samples specifically include:

[0013] S21: Fourier transform infrared spectroscopy scan of finished bone glue;

[0014] S22: Microscopic infrared spectrum scanning of the mural fragments;

[0015] S23: Fourier transform infrared spectroscopy analysis of simulated mural samples.

[0016] Furthermore, the step S3 specifically includes: scanning near-infrared spectra of a variety of commercially available finished bone glues, establishing a classification and identification model in combination with chemometric methods (such as partial least squares method), and using the near-infrared spectrum model to identify the types of bone glue used in mural restoration.

[0017] The research goal of this step is to use the near-infrared spectroscopy model to identify the type of glue used in mural restoration when the type of glue is unknown. The glue here is not limited to bone glue.

[0018] Furthermore, in step S4, a two-step extraction method is used to extract proteins and polypeptides, and the amino acid composition and content of the finished product of bone glue after digestion are analyzed by gas chromatography-mass spectrometry technology, and then the residual amount of bone glue sealing material on the mural fragments is analyzed.

[0019] The two-step extraction method can significantly improve the extraction efficiency of samples, increase the sensitivity of the method, reduce the amount of sample required for detection, and improve the accuracy of amino acid composition and content analysis.

[0020] Quantitative analysis by gas chromatography-mass spectrometry is carried out on the basis of qualitative analysis by infrared spectroscopy. If residual bone glue sealing material is found in the qualitative analysis, quantitative analysis by gas chromatography-mass spectrometry will be carried out.

[0021] Furthermore, in the step S21, the sample is pretreated before the infrared spectrum scanning; there are two pretreatment methods, the first method is to make the bone glue into powder, grind it with KBr and then press it into tablets, the tablet pressing method can make the bone glue have good uniformity, and the scanned infrared spectrum is closer to the actual situation; the second method is to dissolve the bone glue in water, drip it on the KBr that has been pressed into tablets, and dry it under an infrared drying lamp; scan the Fourier transform infrared spectrum of KBr after adding the sample, use the Kramers-Kronig correction spectrum processing method, compare the Fourier transform infrared spectra of all finished bone glues, and find the characteristic absorption peak of bone glue.

[0022] Method 2 is used when method 1 cannot grind the bone glue into a form that meets the requirements for tableting. It can also improve the absorption of bone glue in the infrared spectrum range.

[0023] By using the tabletting method to process the bone glue product for Fourier transform infrared spectroscopy analysis, not only can damage to the hard-earned mural fragments be avoided, but the tabletting method also avoids the problem of disordered microscopic infrared absorption peaks caused by the small and irregular particles of the bone glue product.

[0024] Furthermore, in step S22, a qualitative analysis is performed on whether there is any bone glue remaining on the mural fragments by scanning the mural fragments with a microscopic infrared spectrum, and then the infrared spectrum absorption spectrum of the finished bone glue and the mural fragments is compared to determine whether there is any bone glue remaining on the mural fragments.

[0025] Since the number of mural samples is small and sampling is difficult, the biggest advantage of micro-infrared spectroscopy is that it can perform spectral scanning without destructive testing.

[0026] Furthermore, in step S23, the specific operation of the Fourier transform infrared spectroscopy analysis of the simulated mural sample is: applying a gelatin solution on the simulated mural sample, performing a pretreatment after natural air drying, and then performing Fourier transform infrared spectroscopy analysis.

[0027] There are two pre-treatment methods for simulated mural samples. One is to directly perform microscopic infrared spectroscopy analysis on the simulated samples, which is a non-destructive analysis method; the other is to perform Fourier transform infrared spectroscopy analysis on the simulated mural samples after crushing and grinding them and then performing a tablet test. According to the mural restoration process, the simulated mural samples after glue coating are treated to remove the bone glue. The treated simulated samples are analyzed again by Fourier transform infrared spectroscopy to determine the removal rate of bone glue, and a more effective remover can be selected based on the removal rate.

[0028] Furthermore, the two-step extraction method specifically includes: firstly extracting the hydrophobic protein and the polypeptide using an organic solvent, and then extracting the hydrophilic protein and the polypeptide using an ammonia solution.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] In the present invention, micro-infrared spectroscopy combined with Fourier transform infrared spectroscopy is used to analyze and compare bone glue samples in different states, an infrared spectrum library of bone glue products is jointly established, and an analysis method for qualitatively judging the bone glue residue on mural fragments by infrared spectroscopy is established. The possibility of applying near-infrared spectroscopy in mural cultural relics protection is discussed for the first time, and the sealing materials used when peeling are classified and identified by near-infrared spectroscopy. A model is established by combining chemometric methods such as partial least squares method, and a rapid identification method for analyzing the types of sealing materials by near-infrared spectroscopy is established; a gas chromatography-mass spectrometry analysis method is used to analyze the bone glue products and the bone glue extracted from the mural fragments. Aiming at the problem of low extraction efficiency of bone glue samples, a two-step extraction method is proposed for the first time, the extraction solvent is optimized, the extraction efficiency of hydrophobic proteins and polypeptides is improved, a gas chromatography-mass spectrometry quantitative analysis method of amino acids in bone glue is established, the sensitivity of the method and the accuracy of amino acid composition analysis are improved, a quantitative analysis curve of the bone glue residue on the simulated mural sample is established, and on this basis, the residual amount of bone glue sealing material on the mural fragment is quantitatively determined. The method of the invention has the advantages of high extraction efficiency, good recovery rate and high sensitivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a diagram of the research object of three infrared spectra adopted by the present invention;

[0032] Figure 2 It is the technical roadmap of the present invention. DETAILED DESCRIPTION

[0033] In order to make the purpose and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0034] The instruments, reagents, materials, etc. involved in the following examples, unless otherwise specified, are all conventional instruments, reagents, materials, etc. in the prior art and can be obtained through regular commercial channels. The experimental methods, detection methods, etc. involved in the following examples, unless otherwise specified, are all conventional experimental methods, detection methods, etc. in the prior art.

[0035] Example 1

[0036] Reference Figure 1-2 This embodiment provides a method for analyzing the residual amount of bone glue in the sealing material of murals and cultural relics, which specifically comprises the following steps:

[0037] S1: Sample preparation: Prepare finished bone glue, simulated mural samples, and mural fragments; among them, the finished bone glue is purchased on the market, the mural fragments are provided by researchers from Shaanxi History Museum, and the simulated mural samples are prepared by researchers from Shaanxi History Museum.

[0038] S2: Fourier transform infrared spectroscopy (FTIR) scanning and spectrum processing of three samples;

[0039] S21: Fourier transform infrared spectrum scanning of finished bone glue; the sample is pretreated before infrared spectrum scanning; there are two pretreatment methods, method one is to make bone glue into powder, grind it with KBr and then press it into tablets, the pressing method can make bone glue have good uniformity, and the scanned infrared spectrum is closer to the actual situation; method two is to dissolve bone glue in water, drip it onto the KBr that has been pressed into tablets, and dry it under an infrared drying lamp; scan the Fourier transform infrared spectrum of KBr after adding the sample, use the Kramers-Kronig correction spectrum processing method, compare the Fourier transform infrared spectrum of all finished bone glues, and find the characteristic absorption peak of bone glue. The choice of method two is to use it when method one cannot grind bone glue into a material that meets the requirements of tablet pressing, and it can also improve the absorption of bone glue in the infrared spectrum range. By using the tablet pressing method to process bone glue products for Fourier transform infrared spectroscopy analysis, not only the damage to the hard-won mural fragments is avoided, but the tablet pressing method also avoids the problem of messy microscopic infrared absorption peaks caused by small and irregular particles of bone glue products.

[0040] S22: Microscopic infrared spectroscopy scanning of mural fragments: qualitative analysis is performed on whether there is any bone glue remaining on the mural fragments by microscopic infrared spectroscopy scanning of mural fragments, and then the infrared spectral absorption spectra of the finished bone glue and the mural fragments are compared to determine whether there is any bone glue remaining on the mural fragments. Since the number of mural samples is small and it is difficult to sample, the biggest advantage of microscopic infrared spectroscopy is that it can perform spectral scanning without destructive testing.

[0041] S23: Fourier transform infrared spectroscopy analysis of simulated mural samples. The specific operation of the Fourier transform infrared spectroscopy analysis of simulated mural samples is: apply the bone glue solution on the simulated mural sample, dry it naturally, and then perform the Fourier transform infrared spectroscopy analysis. There are two pre-treatment methods for simulated mural samples. One is to directly perform microscopic infrared spectroscopy analysis on the simulated sample, which is a non-destructive analysis method; the other is to crush and grind the simulated mural sample and then perform the tablet test and then perform the Fourier transform infrared spectroscopy analysis. According to the mural restoration process, the simulated mural sample after the glue is applied is treated to remove the bone glue. The treated simulated sample is analyzed by Fourier transform infrared spectroscopy again to determine the removal rate of bone glue, and a more effective remover is selected according to the removal rate.

[0042] S3: Near-infrared spectral analysis (NIR) of finished bone glue; scan the near-infrared spectra of a variety of commercially available finished bone glues, combine chemometric methods (such as partial least squares method) to establish a classification and identification model, and use the near-infrared spectral model to identify the types of bone glue used in mural restoration.

[0043] S4: Gas chromatography-mass spectrometry (GC-MS) analysis of finished bone glue and mural fragments. The bone glue of the mural fragments was extracted using a two-step extraction method. The amino acid composition and content of the finished bone glue after digestion were analyzed by gas chromatography-mass spectrometry, and then the residual amount of bone glue sealing material on the mural fragments was analyzed. The two-step extraction method specifically includes: first, using an organic solvent (N,N-dimethylformamide, dimethyl sulfoxide, ethanol or isopropanol) to extract hydrophobic proteins and polypeptides, and then using an ammonia solution to extract hydrophilic proteins and polypeptides. The two-step extraction method can significantly improve the extraction efficiency of the sample, improve the sensitivity of the method, and reduce the amount of sample required for detection, while improving the accuracy of amino acid composition and content analysis.

[0044] Through the above method, the extraction efficiency, recovery rate and sensitivity of the GC-MS method in the two-step extraction method are higher than those of the ammonia solution extraction method. The method of this embodiment will be applied to determine the residual bone glue on the removed mural cultural relics (after removing the sealing material), providing a basis for determining the start time of cultural relic restoration work.

[0045] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for analyzing the residual amount of bone glue in mural cultural relics sealing materials, characterized in that: The specific steps include: S1: Sample preparation: prepare finished bone glue, simulated mural samples, and mural fragments; S2: Fourier transform infrared spectrum scanning and spectrum processing of three samples, including: S21: Fourier transform infrared spectroscopy scan of finished bone glue; S22: Microscopic infrared spectrum scanning of the mural fragments; S23: Fourier transform infrared spectroscopy analysis of simulated mural samples; S3: Near infrared spectroscopy analysis of finished bone glue, specifically including: scanning near infrared spectra of various commercially available finished bone glues, establishing a classification and identification model in combination with chemometric methods, and using the near infrared spectroscopy model to identify the types of bone glue used in mural restoration; S4: gas chromatography-mass spectrometry analysis of the finished bone glue and the mural fragments, specifically: extracting proteins and peptides by a two-step extraction method, analyzing the amino acid composition and content of the finished bone glue after digestion by gas chromatography-mass spectrometry, and then analyzing the residual amount of bone glue sealing material on the mural fragments; The two-step extraction method specifically includes: firstly extracting hydrophobic proteins and polypeptides using an organic solvent, and then extracting hydrophilic proteins and polypeptides using an ammonia solution.

2. The method for analyzing the residual amount of bone glue in a mural cultural relic sealing material according to claim 1, characterized in that: In the step S21, the sample is pretreated before the infrared spectrum scanning; there are two pretreatment methods. The first method is to make the bone glue into powder, grind it with KBr and then press it into tablets. The tablet pressing method can make the bone glue have good uniformity and the scanned infrared spectrum is closer to the actual situation; the second method is to dissolve the bone glue in water, drip it onto the KBr that has been pressed into tablets, and dry it under an infrared drying lamp; scan the Fourier transform infrared spectrum of KBr after adding the sample, use the Kramers-Kronig correction spectrum processing method, compare the Fourier transform infrared spectra of all finished bone glues, and find the characteristic absorption peak of bone glue.

3. The method for analyzing the residual amount of bone glue in a mural cultural relic sealing material according to claim 1, characterized in that: In step S22, a qualitative analysis is performed on whether there is any bone glue remaining on the mural fragments by scanning the mural fragments with a microscopic infrared spectrum, and then the infrared spectrum absorption spectrum of the finished bone glue and the mural fragments is compared to determine whether there is any bone glue remaining on the mural fragments.

4. The method for analyzing the residual amount of bone glue in a mural cultural relic sealing material according to claim 1, characterized in that: In step S23, the specific operation of the Fourier transform infrared spectroscopy analysis of the simulated mural sample is: applying a bone glue solution on the simulated mural sample, performing a pre-treatment after natural air drying, and then performing Fourier transform infrared spectroscopy analysis.

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