Study On The Properties Analysis Of Infrared Spectroscopy And GC-MS Of Eight Specices Of Dalbergia Wood And Extractives

Precious timber has the characteristics of better properties,noble color and beautiful texture.It is the principal natural material of many luxury furniture,artwork,medical materials,with extremely high economic and practical value.However,it is difficult to identify species by traditional wood identification technology in the market.Modern analysis technology is still in the initial stage of testing and exploring.At present,there is a lack of a general and systematic accurate identification method.Therefore,it is of great significance to reveal the chemical characteristics of precious wood from the perspective of molecular structure and accurately distinguish precious wood for the implementation of CITES convention,the reduction of trade disputes and the reasonable protection and utilization of precious wood.In this paper,Dalbergia odorifera,Dalbergia stevensonii and Dalbergia sissoo,Dalbergia cultrata,Dalbergia latifolia and Dalbergia melanoxylon,Dalbergia cearensis and Dalbergia congestiflora were used as the research objects.FTIR,SD-IR and 2D-IR techniques were used to discriminate the chemical characteristics of eight species of the genus Dalbergia.Finally,wood species identification system based on the three-step identification of infrared spectroscopy and GC-MS fingerprint characteristic could be built,which can realize accurate identification of precious wood species based on chemical taxonomy.The main conclusions of this paper are as follows:(1)The three-step identification fingerprints of eight species of the genus Dalbergia by infrared spectroscopy were constructed.The FTIR spectra of Dalbergia odorifera,Dalbergia stevensonii and Dalbergia sissoo are similar,among which Dalbergia odorifera and Dalbergia stevensonii are closer,while Dalbergia sissoo contains higher carbonyl compounds.SD-IR fingerprints showed that all of them contained calcium oxalate and more aromatic substances.Dalbergia cultrata,Dalbergia latifolia and Dalbergia melanoxylon have their own characteristic absorption peaks,and Dalbergia latifolia is the easiest to distinguish.SD-IR fingerprints showed that Dalbergia cultrata and Dalbergia melanoxylon had relativelyabundant absorption peaks,with higher calcium oxalate content and more aromatic substances.The FTIR spectra of Dalbergia cearensis showed stronger absorption peak intensity and higher chemical content;SD-IR fingerprints showed that both kinds of wood contained more calcium oxalate and aromatic substances,and Dalbergia cearensis contained more flavonoid extracts.In the 2D-IR fingerprint,only the strongest peak of Dalbergia odorifera belongs to C-O functional group,while the other seven kinds of wood belong to C-O and C=O functional group,which indicates that the two functional groups are sensitive to thermal perturbation and can also distinguish wood by the number of automatic peaks.(2)The three-step identification fingerprints of eight wood extracts of the genus Dalbergia were constructed.The FTIR spectra of Dalbergia odorifera and Dalbergia stevensonii are similar,but which is distinctly different from that of Dalbergia sissoo.Dalbergia odorifera and Dalbergia sissoo contain more carbonyl compounds,while Dalbergia sissoo contains more sulfur compounds.In SD-IR fingerprints,Dalbergia odorifera and Dalbergia stevensonii can be distinguished by the intensity of absorption peaks.The FTIR spectra of Dalbergia cultrata,Dalbergia latifolia and Dalbergia melanoxylon are obviously different.Dalbergia cultrata is rich in carbonyl compounds.Dalbergia melanoxylon may contain more aromatic ether functional groups.Dalbergia cultrata and Dalbergia latifolia contain more sulfur compounds.SD-IR fingerprints could clearly show that the relative intensity of absorption peaks at the same location is different,and some characteristic peaks can be used to distinguish three kinds of wood.The FTIR spectra of extracts from Dalbergia cearensis and Dalbergia congestiflora are similar.Dalbergia cearensis contains more carbonyl compounds.SD-IR fingerprints showed that the absorption peaks of Dalbergia cearensis were more than those of Dalbergia congestiflora,suggesting that Dalbergia cearensis contained more flavonoids.In the 2D-IR fingerprint,the number of automatic peaks of eight kinds of wood is different,and the positions of the strongest peaks are different.The strongest peaks are mainly attributed to C-O,C-O-C and aromatic ring skeleton functional groups,which indicates that the above functional groups are more sensitive to thermal perturbation.(3)The GC-MS fingerprints of eight wood extracts of the genus Dalbergia were constructed.There are only two common compounds in Dalbergia odorifera,Dalbergia stevensonii and Dalbergia sissoo,and the number of characteristic components is 7,11,5,respectively.2-(3,4-dimethoxyphenyl)-6-hydroxy-4-chlormanone,medidaldehyde,8-methyl-2-nitro-10H-dibenzo [b,f] [1,4] oxazapine-11-one exhibited the highest relative content.There are only two identical compounds in Dalbergia cultrata,Dalbergia latifolia and Dalbergia melanoxylon,with the number of characteristic components being 3,4,5,respectively.The highest relative contents are 7-methoxy-1-thioflavone,4,2’,3’,4’-tetramethoxy-5’-methyl-6-methyl-aminomethyl-1,1’-biphenyl,10,11-dihydro-10-hydroxy-2,3,6-trimethoxydibenzo(b,f)bezoar.Dalbergia cearensis and Dalbergia congestiflora have very similar extracts.Only Dalbergia cearensis has Formononetin,but the relative content of the same chemical constituents is different.The highest content of Dalbergia cearensis is 4-methyl-2-[5-(2-thiophenyl)pyrazole-3-yl] phenol,which is twice as much as Dalbergia congestiflora.The highest relative content of Dalbergia congestiflora is 3-(4-hydroxy-2-methoxy).Phenyl-7-tryptophan,equivalent to four times of Dalbergia cearensis.(4)FTIR,SD-IR and 2D-IR techniques were used to characterize the functional groups of wood and extracts.GC-MS method was used to qualitative and quantitative analysis the primary and unique extractive components.The primary and feature components discrimination of extractives could promote the correct identification for the functional groups characteristic of infrared spectrum.The two methods support and corroborate each other.In summary,this paper successfully build a wood species identification system based on the three-step identification of infrared spectroscopy and GC-MS fingerprint characteristic,which can achieve the purpose of precise identification of wood species and provide a scientific evidence for wood trade and the performance of CITES convention.