The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples...The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples of five different geographic origins: Eastern China.Central China.South-western China,North-western China and North-eastern China.Principal component analysis and SIMCA are applied to effectively classifying the samples according to the origin of the plants.The chemical information contained in the high resolution gas chromatographic data is sufficient to characterize the geographic origin of sam- pies.展开更多
The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/M...The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.展开更多
Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen h...Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen high-yielding varieties,hence rapid determination of rubber content is essential for the screening.Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost.Near-infrared spectroscopy analysis technology,which has developed rapidly in the field of industrial process analysis in recent years,is a green detection technology with obvious merits of fast measurement speed,low cost and no sample loss.This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots.Pyrolysis gas chromatography(Py-GC)was chosen as the reference method for the development of NIR prediction model.208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China.Near-infrared spectra were acquired for all samples.Randomly,two-thirds of them were selected as the calibration set,the remaining one-third as the validation set,and the partial least squares method was successfully established a good NIR prediction model for rubber content at 1080-1800 nm with a ratio of performance to deviation(RPD)of 5.54 and coefficient of determination(R^(2))of 0.95.This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland,and could greatly facilitate TKS germplasm preservation,high-yield cultivation,environment-friendly,high-efficiency and low-cost rubber extraction,and comprehensive advancement of the natural rubber industry thereof.展开更多
文摘The combination of pyrolysis high resolution gas chromatography and pat- tern recognition techniques is a powerful tool for the classification of traditional Chinese drug.A study has been completed on 55 Beimu samples of five different geographic origins: Eastern China.Central China.South-western China,North-western China and North-eastern China.Principal component analysis and SIMCA are applied to effectively classifying the samples according to the origin of the plants.The chemical information contained in the high resolution gas chromatographic data is sufficient to characterize the geographic origin of sam- pies.
文摘The composition and sequence distribution of monomeric units in polyester polyether multiblock copolymer were studied by pyrolysis? gas chromatography (PGC) and pyrolysis gas chromatography/mass spectrometry (PGC/MS). PGC was applied to study the F t curve of the multiblock copolymer and PGC/MS was used to separate and identify the pyrolyzates. DTA experiment was used to study the decomposition temperature. The results show that the beginning point of elastomer’s decomposition was about 300?℃ and the decomposition temperature of most of the sample was 550?℃. Many pyrolyzates were produced because of the breaking of weak bonds in the sample. The possible microstructure was verified and the pyrolysis pathway of the copolymer was investigated.
基金supported by Beijing University of Chemical Technology-China-Japan Friendship Hospital Biomedical Translation Engineering Research Center Joint Project (RZ2020-02)the sponsorship provided by Beijing Linglong Dandelion Science&Technology Development Co.,Ltd.the financial support granted by the National Key Research and Development Program of China (2019YFF0302004)
文摘Taraxacum kok-saghyz(TKS)is a plant native to the Tianshan valley on the border between China and Kazakhstan.TKS rubber is a good substitute for natural rubber.TKS's breeding work necessitates the need to screen high-yielding varieties,hence rapid determination of rubber content is essential for the screening.Conventional analytical methods cannot meet actual needs in terms of real-time testing and economic cost.Near-infrared spectroscopy analysis technology,which has developed rapidly in the field of industrial process analysis in recent years,is a green detection technology with obvious merits of fast measurement speed,low cost and no sample loss.This research aims to develop a portable non-destructive near-infrared spectroscopic detection scheme to evaluate the content of natural rubber in TKS fresh roots.Pyrolysis gas chromatography(Py-GC)was chosen as the reference method for the development of NIR prediction model.208 TKS fresh root samples were collected from the Inner Mongolia Autonomous Region of China.Near-infrared spectra were acquired for all samples.Randomly,two-thirds of them were selected as the calibration set,the remaining one-third as the validation set,and the partial least squares method was successfully established a good NIR prediction model for rubber content at 1080-1800 nm with a ratio of performance to deviation(RPD)of 5.54 and coefficient of determination(R^(2))of 0.95.This study showed that portable near-infrared spectroscopy could be used with ease for large-scale screening of TKS plants in farmland,and could greatly facilitate TKS germplasm preservation,high-yield cultivation,environment-friendly,high-efficiency and low-cost rubber extraction,and comprehensive advancement of the natural rubber industry thereof.
