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2018 Volume 46 Issue 9
2018, 46(9): 1329-1338
doi: 10.11895/j.issn.0253-3820.181340
Abstract:
Live cell imaging is an essential tool for detecting intracellular biomolecules, particularly those that are key targets in disease processes and monitoring their functions in live cells. Usually, the intracellular biomolecules cannot make out signal change that could be detected by instrument or naked eye directly. Thus, target identification and validation with high-affinity probes is one of the key prerequisites for interrogation of specific molecular targets in living systems. There are many kinds of bioprobes. Among them, fluorescent bioprobes based on nucleic acids are essential tools due to their high sensitivity, fast response, simplicity, real-time, on-site and non-invasive visualization of biological molecules and processes in live cells. They not only provide valuable insight in understanding physiological alterations in pathological settings but also serve as useful tools for the development of personalized medicine and targeted therapies. This review summarizes the progress of fluorescent bioprobes based on nucleic acids for live cell imaging in recent 5 years.
Live cell imaging is an essential tool for detecting intracellular biomolecules, particularly those that are key targets in disease processes and monitoring their functions in live cells. Usually, the intracellular biomolecules cannot make out signal change that could be detected by instrument or naked eye directly. Thus, target identification and validation with high-affinity probes is one of the key prerequisites for interrogation of specific molecular targets in living systems. There are many kinds of bioprobes. Among them, fluorescent bioprobes based on nucleic acids are essential tools due to their high sensitivity, fast response, simplicity, real-time, on-site and non-invasive visualization of biological molecules and processes in live cells. They not only provide valuable insight in understanding physiological alterations in pathological settings but also serve as useful tools for the development of personalized medicine and targeted therapies. This review summarizes the progress of fluorescent bioprobes based on nucleic acids for live cell imaging in recent 5 years.
2018, 46(9): 1339-1349
doi: 10.11895/j.issn.0253-3820.171119
Abstract:
Alzheimer's disease (AD) is a neurodegenerative disease with unknown etiology. Beta-amyloid protein (Aβ) is one of the specific biomarkers of AD, and many clinical studies suggest that abnormal levels of Aβ in blood, cerebrospinal fluid and brain tissue are closely related to the progression of AD. The analysis and evaluation of Aβ is important for early detection, tracking, prevention and treatment of AD. In this paper, the present situation of the commonly used detection methods of Aβ at home and abroad was summarized and compared. Specifically, the latest application of new electrochemical biosensor in Aβ detection was mainly described, and the summary of its future directions and the potential applications was given. It is intended to provide reference for the further research and application of Aβ.
Alzheimer's disease (AD) is a neurodegenerative disease with unknown etiology. Beta-amyloid protein (Aβ) is one of the specific biomarkers of AD, and many clinical studies suggest that abnormal levels of Aβ in blood, cerebrospinal fluid and brain tissue are closely related to the progression of AD. The analysis and evaluation of Aβ is important for early detection, tracking, prevention and treatment of AD. In this paper, the present situation of the commonly used detection methods of Aβ at home and abroad was summarized and compared. Specifically, the latest application of new electrochemical biosensor in Aβ detection was mainly described, and the summary of its future directions and the potential applications was given. It is intended to provide reference for the further research and application of Aβ.
2018, 46(9): 1350-1356
doi: 10.11895/j.issn.0253-3820.181317
Abstract:
During the past few years, electrochemical sensing techniques based on ion channels have attracted considerable attention. Nowadays, these techniques have been widely used in DNA sequencing, measurement of molecular interactions and detection of inorganic ions and biological species. Hence, in this review, the research progresses of ion channel-based electrochemical techniques including amperometry, conductometry and potentiometry in chemical and biological sensing are addressed from the perspective of different electrochemical methods. The sensing mechanism and fabrication process of these sensing methods are mainly introduced. In addition, the further research orientations of electrochemical sensing based on ion channels are prospected.
During the past few years, electrochemical sensing techniques based on ion channels have attracted considerable attention. Nowadays, these techniques have been widely used in DNA sequencing, measurement of molecular interactions and detection of inorganic ions and biological species. Hence, in this review, the research progresses of ion channel-based electrochemical techniques including amperometry, conductometry and potentiometry in chemical and biological sensing are addressed from the perspective of different electrochemical methods. The sensing mechanism and fabrication process of these sensing methods are mainly introduced. In addition, the further research orientations of electrochemical sensing based on ion channels are prospected.
2018, 46(9): 1357-1362
doi: 10.11895/j.issn.0253-3820.181293
Abstract:
Two kinds of ssDNA-GNPs(PolyG1-GNPs and PolyG2-GNPs) were synthesized by modification of two different G-rich single-strand oligonucleotides(PolyG1 and PolyG2) onto 13-nm gold nanoparticles (GNP) surface through formation of the sulfur-gold covalent bond, respectively. The as-prepared PolyG1-GNPs and PolyG2-GNPs had reasonable colloidal stability in complex dispersing matrices. The effect of ssDNA sequence on the interaction between ssDNA-GNPs and cells was systematically investigated by UV-vis absorption spectroscopy, cellular transmission electronic microscopy and inductively coupled plasma mass spectrometry. The experimental results showed that both of the as-prepared PolyG1-GNPs and PolyG2-GNPs had low cytotoxicity and exhibited energy related endocytosis. In addition, the cellular internalization amount and dispersibility of ssDNA-GNPs were strongly affected by the sequences of immobilized ssDNA. PolyG2 with G4 secondary structure could significantly increase the cellular internalization amount and intracellular stability of PolyG2-GNPs.
Two kinds of ssDNA-GNPs(PolyG1-GNPs and PolyG2-GNPs) were synthesized by modification of two different G-rich single-strand oligonucleotides(PolyG1 and PolyG2) onto 13-nm gold nanoparticles (GNP) surface through formation of the sulfur-gold covalent bond, respectively. The as-prepared PolyG1-GNPs and PolyG2-GNPs had reasonable colloidal stability in complex dispersing matrices. The effect of ssDNA sequence on the interaction between ssDNA-GNPs and cells was systematically investigated by UV-vis absorption spectroscopy, cellular transmission electronic microscopy and inductively coupled plasma mass spectrometry. The experimental results showed that both of the as-prepared PolyG1-GNPs and PolyG2-GNPs had low cytotoxicity and exhibited energy related endocytosis. In addition, the cellular internalization amount and dispersibility of ssDNA-GNPs were strongly affected by the sequences of immobilized ssDNA. PolyG2 with G4 secondary structure could significantly increase the cellular internalization amount and intracellular stability of PolyG2-GNPs.
2018, 46(9): 1363-1371
doi: 10.11895/j.issn.0253-3820.181027
Abstract:
A monolithic micro gas chromatography (μGC) chip integrated by a micro separation column (μSC) and a micro thermal conductivity detector (μTCD) was fabricated based on micro-electro-mechanical system (MEMS) technique. Compared with the state of the art, the μSC with high depth-to-width ratio channels, coated with mesoporous silica nanoparticles as stationary phase, could effectively improve the column capacity and separation performance. Besides, the stable suspending μTCD, which was designed and fabricated in two ports of the μGC chip, could availably enhance the thermal isolation and reliability of the device. The mixture of light hydrocarbons (methane, ethane, propane and butane) could be separated by base line and detected by this monolithic integrated μGC chip, in which the overall analysis and detection time was only 33 seconds, the separation resolution of ethane and propane was 8.34, and the number of theoretical plates was as high as 11420. This monolithic integrated μGC chip had the advantages including good separation resolution, high column efficiency and short analysis time, which was highly suitable for portable gas chromatographic field and onsite detection.
A monolithic micro gas chromatography (μGC) chip integrated by a micro separation column (μSC) and a micro thermal conductivity detector (μTCD) was fabricated based on micro-electro-mechanical system (MEMS) technique. Compared with the state of the art, the μSC with high depth-to-width ratio channels, coated with mesoporous silica nanoparticles as stationary phase, could effectively improve the column capacity and separation performance. Besides, the stable suspending μTCD, which was designed and fabricated in two ports of the μGC chip, could availably enhance the thermal isolation and reliability of the device. The mixture of light hydrocarbons (methane, ethane, propane and butane) could be separated by base line and detected by this monolithic integrated μGC chip, in which the overall analysis and detection time was only 33 seconds, the separation resolution of ethane and propane was 8.34, and the number of theoretical plates was as high as 11420. This monolithic integrated μGC chip had the advantages including good separation resolution, high column efficiency and short analysis time, which was highly suitable for portable gas chromatographic field and onsite detection.
2018, 46(9): 1372-1378
doi: 10.11895/j.issn.0253-3820.171318
Abstract:
Self-made surface charge switching amino-SiO2@Fe3O4 magnetic composite microspheres were applied to microfluidic chip, and DNA solid phase extraction chip of polymethyl methacrylate (PMMA) was fabricated by laser etching and hot pressing bonding. The magnetic beads that could be controlled by permanent magnet were injected into the chip channel to obtain a magnetic bead chip for genomic DNA extraction in human whole blood. Under the optimized extraction conditions (with 80 μg beads, flow rate for adsorption, elution and desorption were 10, 5 and 20 μL/min, respectively), the extracted products were subjected to gel electrophoresis and PCR test. The results showed that the genomic DNA with high purity was extracted from the whole blood by magnetic bead microfluidic chip. The extraction efficiency was about 35%. The gel electrophoresis band of the extract was consistent with the genomic DNA extracted by commercial reagent kit. The extract solution could be used for further PCR reaction.
Self-made surface charge switching amino-SiO2@Fe3O4 magnetic composite microspheres were applied to microfluidic chip, and DNA solid phase extraction chip of polymethyl methacrylate (PMMA) was fabricated by laser etching and hot pressing bonding. The magnetic beads that could be controlled by permanent magnet were injected into the chip channel to obtain a magnetic bead chip for genomic DNA extraction in human whole blood. Under the optimized extraction conditions (with 80 μg beads, flow rate for adsorption, elution and desorption were 10, 5 and 20 μL/min, respectively), the extracted products were subjected to gel electrophoresis and PCR test. The results showed that the genomic DNA with high purity was extracted from the whole blood by magnetic bead microfluidic chip. The extraction efficiency was about 35%. The gel electrophoresis band of the extract was consistent with the genomic DNA extracted by commercial reagent kit. The extract solution could be used for further PCR reaction.
2018, 46(9): 1379-1385
doi: 10.11895/j.issn.0253-3820.171456
Abstract:
Taxus chinensis (Pilger) Rehd. is one of the most important medicinal plants. According to the characteristics of the needles, a new RNA extraction method, CTAB-LiCl, was developed. RNA was extracted from young and mature needles of Taxus Chinensis by TRIzol method. The result showed that the quality of RNA extracted from young needles was complete, and that of RNA from mature needles was incomplete. As a comparison, cetyl trimethyl ammonium bromide (CTAB) method, SDS-phenol method and improved CTAB-LiCl method were respectively used for extraction of RNA from mature needles. The comparative result showed that the quality of RNA extracted by CTAB method and SDS-phenol method was incomplete, accompanied with different degrees of contamination of polysaccharides, polyphenols and DNA. The improved CTAB-LiCl method could better extract RNA from mature needles. The ratio of A260/A280 was in the range of 1.9-2.0, and the yield of RNA was the highest, which was 1.37 and 1.24 times compared with that by CTAB and SDS phenol extraction, respectively. The reverse transcription cDNA was further tested through PCR with the specific primers. The amplified fragments displayed in clear and bright bands in accordance with the expected size. High quality RNA from mature needles has more advantages in molecular biology study of Taxus chinensis.
Taxus chinensis (Pilger) Rehd. is one of the most important medicinal plants. According to the characteristics of the needles, a new RNA extraction method, CTAB-LiCl, was developed. RNA was extracted from young and mature needles of Taxus Chinensis by TRIzol method. The result showed that the quality of RNA extracted from young needles was complete, and that of RNA from mature needles was incomplete. As a comparison, cetyl trimethyl ammonium bromide (CTAB) method, SDS-phenol method and improved CTAB-LiCl method were respectively used for extraction of RNA from mature needles. The comparative result showed that the quality of RNA extracted by CTAB method and SDS-phenol method was incomplete, accompanied with different degrees of contamination of polysaccharides, polyphenols and DNA. The improved CTAB-LiCl method could better extract RNA from mature needles. The ratio of A260/A280 was in the range of 1.9-2.0, and the yield of RNA was the highest, which was 1.37 and 1.24 times compared with that by CTAB and SDS phenol extraction, respectively. The reverse transcription cDNA was further tested through PCR with the specific primers. The amplified fragments displayed in clear and bright bands in accordance with the expected size. High quality RNA from mature needles has more advantages in molecular biology study of Taxus chinensis.
2018, 46(9): 1386-1392
doi: 10.11895/j.issn.0253-3820.181285
Abstract:
X-ray fluorescence (XRF) spectrometry has been widely used for elemental analysis of a wide variety of samples due to its important features such as acceptable speed, economy and nondestructive for samples. Portable energy dispersive X-ray fluorescence spectrometry (EDXRF) is a key technology for on-site determination. However, the poor detection limits make the conventional XRF direct analysis unsatisfactory for liquid samples. Therefore, a proper pre-concentration procedure is needed to decrease the detection limit. In this study, we prepared a kind of three-dimensional flower-shaped magnesium silicate (3DFMS). Due to the high surface area, large pore size and hierarchical nanostructures, 3DFMS was employed as a solid sorbent for selective pre-concentration of Pb2+, Zn2+ and Cu2+. And then portable EDXRF was applied to directly quantify. The structure and morphology of 3DFMS were characterized by X-ray diffraction, scanning and transmission electron microscopes. The related adsorption and detect conditions have been optimized. Under the optimal conditions (100 mg of adsorbent dose, 150 mL of water, pH 4 and 10 min of sorption time), the detection limits (S/N=3) for Pb2+, Zn2+ and Cu2+ were 0.57, 0.69 and 0.76 μg/L, respectively. The linear range was 2.0-240 μg/L for three elements. Furthermore, the recovery of metal ions in the actual water sample was 88.0%-118.0%. The relative standard deviations for five successive measurements were 3.8%-5.0% for 100 μg/L metal ions. The actual water sample was also determined by the proposed method. This present method is rapid, simple, free of organic reagent pollution and low in cost, which is suitable for the rapid determination of trace lead, zinc and copper ions in water.
X-ray fluorescence (XRF) spectrometry has been widely used for elemental analysis of a wide variety of samples due to its important features such as acceptable speed, economy and nondestructive for samples. Portable energy dispersive X-ray fluorescence spectrometry (EDXRF) is a key technology for on-site determination. However, the poor detection limits make the conventional XRF direct analysis unsatisfactory for liquid samples. Therefore, a proper pre-concentration procedure is needed to decrease the detection limit. In this study, we prepared a kind of three-dimensional flower-shaped magnesium silicate (3DFMS). Due to the high surface area, large pore size and hierarchical nanostructures, 3DFMS was employed as a solid sorbent for selective pre-concentration of Pb2+, Zn2+ and Cu2+. And then portable EDXRF was applied to directly quantify. The structure and morphology of 3DFMS were characterized by X-ray diffraction, scanning and transmission electron microscopes. The related adsorption and detect conditions have been optimized. Under the optimal conditions (100 mg of adsorbent dose, 150 mL of water, pH 4 and 10 min of sorption time), the detection limits (S/N=3) for Pb2+, Zn2+ and Cu2+ were 0.57, 0.69 and 0.76 μg/L, respectively. The linear range was 2.0-240 μg/L for three elements. Furthermore, the recovery of metal ions in the actual water sample was 88.0%-118.0%. The relative standard deviations for five successive measurements were 3.8%-5.0% for 100 μg/L metal ions. The actual water sample was also determined by the proposed method. This present method is rapid, simple, free of organic reagent pollution and low in cost, which is suitable for the rapid determination of trace lead, zinc and copper ions in water.
2018, 46(9): 1393-1399
doi: 10.11895/j.issn.0253-3820.171172
Abstract:
Neodymium (Nd) isotopes are widely used for oceanographic processes because of its stable properties in nature. Due to the low concentration of Nd in the seawater, pre-separation and enrichment are necessary in the analysis of Nd isotopes. The traditional separation method usually uses co-precipitation with hydrous Fe oxide to separate rare earth elements (REEs), and LN resin to separate and purify Sm and Nd, respectively. But the concentration process is time-consuming. In this work, a concentration method for REEs in seawater was developed on the basis of NOBIAS resin. The experimental conditions of this method, such as the range of pH, elution acid concentration of NOBIAS resin, and elution acid volume for LN -C50-A resin were optimized. The results indicated that, at pH 4.7, the recovery of Nd was about 99% when pre-concentrated with NOBIAS resin and the recovery of Nd was over 93% when purified with LN-C50-A resin. The method showed an excellent experimental reproducibility (RSD<1.5%; n=3) and a very low systematic error (RSD<5%, n=5) in the determination of Nd and its isotope.
Neodymium (Nd) isotopes are widely used for oceanographic processes because of its stable properties in nature. Due to the low concentration of Nd in the seawater, pre-separation and enrichment are necessary in the analysis of Nd isotopes. The traditional separation method usually uses co-precipitation with hydrous Fe oxide to separate rare earth elements (REEs), and LN resin to separate and purify Sm and Nd, respectively. But the concentration process is time-consuming. In this work, a concentration method for REEs in seawater was developed on the basis of NOBIAS resin. The experimental conditions of this method, such as the range of pH, elution acid concentration of NOBIAS resin, and elution acid volume for LN -C50-A resin were optimized. The results indicated that, at pH 4.7, the recovery of Nd was about 99% when pre-concentrated with NOBIAS resin and the recovery of Nd was over 93% when purified with LN-C50-A resin. The method showed an excellent experimental reproducibility (RSD<1.5%; n=3) and a very low systematic error (RSD<5%, n=5) in the determination of Nd and its isotope.
2018, 46(9): 1400-1407
doi: 10.11895/j.issn.0253-3820.171373
Abstract:
A method for simultaneous determination of perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), perfluoroalkyl phosphonic acids (PFPAs), perfluoroalkyl phosphinic acids (PFPis) and polyfluoroalkyl phosphoric acid diesters (diPAPs) from water by solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) was established. During solid phase extraction process, 6 mL of ammonia-methanol (1.0%, V/V), 12 mL of methanol, 12 mL of ultrapure water were used to activate the WAX cartridges. After sample loading, the cartridges were eluted with 6 mL of ammonia-acetonitrile (0.5%, V/V), 6 mL of ammonia-methanol (1.0%, V/V) and 6 mL ammonia-acetonitrile (1.0%, V/V). Before instrumental analysis, the sample extract was divided into three parts. For the PFCAs and PFSAs, equal parts of ultrapure water were added to the extract. For the PFPAs, equal parts of 25 mmol/L of tetra-butyl ammonium sulfate were added to the extract. For the PFPis and diPAPs, the solution was methanol. The results showed that the recoveries of target compounds were between 55%-125% with relative standard deviation varying from 0.30% to 15%. Method detection limit and quantitative limit were 0.003-0.215 ng/L and 0.01-0.714 ng/L, respectively. This method was simple with high sensitivity and good reproducibility, and suitable for simultaneous determination of five kinds of per-and polyfluorinated substances in water.
A method for simultaneous determination of perfluoroalkyl carboxylic acids (PFCAs), perfluoroalkyl sulfonic acids (PFSAs), perfluoroalkyl phosphonic acids (PFPAs), perfluoroalkyl phosphinic acids (PFPis) and polyfluoroalkyl phosphoric acid diesters (diPAPs) from water by solid phase extraction-ultra performance liquid chromatography-tandem mass spectrometry (SPE-UPLC-MS/MS) was established. During solid phase extraction process, 6 mL of ammonia-methanol (1.0%, V/V), 12 mL of methanol, 12 mL of ultrapure water were used to activate the WAX cartridges. After sample loading, the cartridges were eluted with 6 mL of ammonia-acetonitrile (0.5%, V/V), 6 mL of ammonia-methanol (1.0%, V/V) and 6 mL ammonia-acetonitrile (1.0%, V/V). Before instrumental analysis, the sample extract was divided into three parts. For the PFCAs and PFSAs, equal parts of ultrapure water were added to the extract. For the PFPAs, equal parts of 25 mmol/L of tetra-butyl ammonium sulfate were added to the extract. For the PFPis and diPAPs, the solution was methanol. The results showed that the recoveries of target compounds were between 55%-125% with relative standard deviation varying from 0.30% to 15%. Method detection limit and quantitative limit were 0.003-0.215 ng/L and 0.01-0.714 ng/L, respectively. This method was simple with high sensitivity and good reproducibility, and suitable for simultaneous determination of five kinds of per-and polyfluorinated substances in water.
2018, 46(9): 1408-1414
doi: 10.11895/j.issn.0253-3820.181261
Abstract:
Exosomes are a series of extracellular vesicles, which are the source of biomarkers. However, there are no sensitive and efficient methods for the isolation of saliva exosome proteins. In this work, we explored the effect of isolation of saliva exosome by ExoQuick (EQ) and ultracentrifugation (UC) method, and the effect of UREA buffer, RIPA lysate, and SDS lysate on exosome protein extraction by nano-liquidchromatography-high-resolution tandem mass spectrometry. The quantitative results of Brodford method showed that the protein content of exosomes obtained by EQ method from 0.5 mL of saliva was higher than that by UC method from 2 mL of saliva. Further mass spectrometry analysis showed that the former identified more proteins than the latter. The effect of the combination of using EQ method and UREA buffer to obtain saliva exosomes proteins was the best. With this method, a total of 194 proteins were identified. The method had good reproducibility, low sample requirement, and stable mass spectrometry detection, and could provide methodological support for finding markers of disease in saliva exosomes.
Exosomes are a series of extracellular vesicles, which are the source of biomarkers. However, there are no sensitive and efficient methods for the isolation of saliva exosome proteins. In this work, we explored the effect of isolation of saliva exosome by ExoQuick (EQ) and ultracentrifugation (UC) method, and the effect of UREA buffer, RIPA lysate, and SDS lysate on exosome protein extraction by nano-liquidchromatography-high-resolution tandem mass spectrometry. The quantitative results of Brodford method showed that the protein content of exosomes obtained by EQ method from 0.5 mL of saliva was higher than that by UC method from 2 mL of saliva. Further mass spectrometry analysis showed that the former identified more proteins than the latter. The effect of the combination of using EQ method and UREA buffer to obtain saliva exosomes proteins was the best. With this method, a total of 194 proteins were identified. The method had good reproducibility, low sample requirement, and stable mass spectrometry detection, and could provide methodological support for finding markers of disease in saliva exosomes.
2018, 46(9): 1415-1423
doi: 10.11895/j.issn.0253-3820.181286
Abstract:
At present, little is known about metabolic mechanism of uremia. In this study, uremia was investigated by combination of NMR spectroscopy, statistical analysis and urinary biochemical assays to provide the basis of the metabolic characteristics of uremia. The characteristic metabolites of uremia were identified from the urine of the uremia patients. The results showed that the urinary levels of 2-hydroxyisobutyrate, 3-hydroxybutyrate, acetone, butyrate, glutamate, sarcosine, creatinine, lysine, N,N-dimethylglycine, citrate, asparagine, ethanol and ethanolamine were reduced, while the urinary levels of branched-chain amino acids (including leucine, valine and isoleucine), taurine, lactate and glucose were higher in uremia patients than that in the healthy subjects. The corresponding disturbed metabolic pathways were derived from the characteristic metabolites, in which amino acid, energy and lipid metabolisms were involved. The specific characteristic metabolites will help to understand the underlying biochemical mechanisms of the onset of uremia.
At present, little is known about metabolic mechanism of uremia. In this study, uremia was investigated by combination of NMR spectroscopy, statistical analysis and urinary biochemical assays to provide the basis of the metabolic characteristics of uremia. The characteristic metabolites of uremia were identified from the urine of the uremia patients. The results showed that the urinary levels of 2-hydroxyisobutyrate, 3-hydroxybutyrate, acetone, butyrate, glutamate, sarcosine, creatinine, lysine, N,N-dimethylglycine, citrate, asparagine, ethanol and ethanolamine were reduced, while the urinary levels of branched-chain amino acids (including leucine, valine and isoleucine), taurine, lactate and glucose were higher in uremia patients than that in the healthy subjects. The corresponding disturbed metabolic pathways were derived from the characteristic metabolites, in which amino acid, energy and lipid metabolisms were involved. The specific characteristic metabolites will help to understand the underlying biochemical mechanisms of the onset of uremia.
2018, 46(9): 1424-1431
doi: 10.11895/j.issn.0253-3820.181164
Abstract:
Lycopene is an important nutrient quality of tomato and has attracted people's attention in recent years. The traditional way of detecting lycopene damages tomatoes and takes a long time. So it is necessary to explore a method for nondestructive detection of lycopene. Due to the large differences in tomato composition, we chose transmission as a detection method and designed a visible/near infrared transmission spectrum detection system. Using this system, tomato transmission spectra were collected and then pretreated with Savitzky-Golay detrend (DT), standard normal variable transformation (SNV), muliplication scattering correction (MSC), normalize (NOR) and first derivative (FD). Finally, partial least squares model was established after processing. The model established by the SNV pre-processed spectrum had the best effect. The correlation coefficients between the calibration set and the verification set were 0.9771 and 0.9504, respectively. The root mean square errors of the calibration set and verification set were 0.9711 mg/kg and 1.0496 mg/kg. Considering that the original spectrum contained too many independent variables, uninformative variable elimination (UVE), successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were used to optimize the variables. The three methods constituted five schemes (UVE, SPA, CARS, UVE-SPA, UVE-CARS). Among these five treatments, the lycopene prediction model was the best after UVE-CARS. The correlation coefficients of the calibration set and validation set increased to 0.9830 and 0.9741, respectively, and the root mean square errors decreased to 0.6919 mg/kg and 0.7680 mg/kg, respectively. In addition, 25 tomato samples were used to externally verify the established model. The correlation coefficient of the prediction set of the UVE-CARS-PLS model was 0.9812, the root mean square error of the prediction set was 0.7071 mg/kg, and the average relative error was 4.32%. As a comparison, the correlation coefficient of the prediction set of the full-spectrum model was 0.951, the root mean square error was 1.0610 mg/kg, and the average relative error was 5.981%. The results showed that compared with the full-spectrum PLS model, UVE-CARS-PLS could greatly simplify the model, improve the model accuracy, and reduce the detection error limit. The result showed that the method with the combination of visible/near-infrared transmission spectroscopy and spectral processing methods could be used for the rapid and non-destructive detection of lycopene content.
Lycopene is an important nutrient quality of tomato and has attracted people's attention in recent years. The traditional way of detecting lycopene damages tomatoes and takes a long time. So it is necessary to explore a method for nondestructive detection of lycopene. Due to the large differences in tomato composition, we chose transmission as a detection method and designed a visible/near infrared transmission spectrum detection system. Using this system, tomato transmission spectra were collected and then pretreated with Savitzky-Golay detrend (DT), standard normal variable transformation (SNV), muliplication scattering correction (MSC), normalize (NOR) and first derivative (FD). Finally, partial least squares model was established after processing. The model established by the SNV pre-processed spectrum had the best effect. The correlation coefficients between the calibration set and the verification set were 0.9771 and 0.9504, respectively. The root mean square errors of the calibration set and verification set were 0.9711 mg/kg and 1.0496 mg/kg. Considering that the original spectrum contained too many independent variables, uninformative variable elimination (UVE), successive projections algorithm (SPA) and competitive adaptive reweighted sampling (CARS) were used to optimize the variables. The three methods constituted five schemes (UVE, SPA, CARS, UVE-SPA, UVE-CARS). Among these five treatments, the lycopene prediction model was the best after UVE-CARS. The correlation coefficients of the calibration set and validation set increased to 0.9830 and 0.9741, respectively, and the root mean square errors decreased to 0.6919 mg/kg and 0.7680 mg/kg, respectively. In addition, 25 tomato samples were used to externally verify the established model. The correlation coefficient of the prediction set of the UVE-CARS-PLS model was 0.9812, the root mean square error of the prediction set was 0.7071 mg/kg, and the average relative error was 4.32%. As a comparison, the correlation coefficient of the prediction set of the full-spectrum model was 0.951, the root mean square error was 1.0610 mg/kg, and the average relative error was 5.981%. The results showed that compared with the full-spectrum PLS model, UVE-CARS-PLS could greatly simplify the model, improve the model accuracy, and reduce the detection error limit. The result showed that the method with the combination of visible/near-infrared transmission spectroscopy and spectral processing methods could be used for the rapid and non-destructive detection of lycopene content.
2018, 46(9): 1432-1437
doi: 10.11895/j.issn.0253-3820.170123
Abstract:
A fast analytical method for organic tracers from biomass burning emissions including levoglucosan, mannosan and galactosan was developed using high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) without derivatization process. The optimum analytical conditions were established as follows:ammonium hydroxide (0.005%, w/V) as mobile phase with a flow rate of 0.35 mL/min, column temperature of 45℃, and negative ion electrospray ionization. Under the optimal analytical conditions, the linear concentration ranges of these organic tracers were 0.01-1 mg/L (R2>0.999) and limits of detection (LOD) were 1.8 μg/L for levoglucosan, 5.8 μg/L for mannosan and 9.5 μg/L for galactosan, respectively. This new method was validated and applied to the detection of real aerosol samples, and was proved to be accurate, fast and sensitive for analysis of organic tracers from biomass burning emissions.
A fast analytical method for organic tracers from biomass burning emissions including levoglucosan, mannosan and galactosan was developed using high performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) without derivatization process. The optimum analytical conditions were established as follows:ammonium hydroxide (0.005%, w/V) as mobile phase with a flow rate of 0.35 mL/min, column temperature of 45℃, and negative ion electrospray ionization. Under the optimal analytical conditions, the linear concentration ranges of these organic tracers were 0.01-1 mg/L (R2>0.999) and limits of detection (LOD) were 1.8 μg/L for levoglucosan, 5.8 μg/L for mannosan and 9.5 μg/L for galactosan, respectively. This new method was validated and applied to the detection of real aerosol samples, and was proved to be accurate, fast and sensitive for analysis of organic tracers from biomass burning emissions.
2018, 46(9): 1438-1445
doi: 10.11895/j.issn.0253-3820.181151
Abstract:
A new method based on alternating trilinear decomposition assisted three-dimensional room temperature phosphorescence (ATLD-TRTP) was developed for fast quantitative determination of acenaphthene (ACE) contents in samples of air-pollution source. The contents of ACE in air-pollution source samples, such as greasy dirt, oil smoke and flue dust in Loudi city were detected after simple sample pretreatment. Using ATLD algorithm (n=5), the average recoveries of ACE were 90.5%±7.9%, 99.4%±6.1% and 101.4%±10.9%, respectively, the root-mean-square errors of prediction (RMSEP) were 0.25, 0.12 and 0.20 μg/mL, respectively, and the limits of detection (LOD) were 39.2, 18.9 and 31.0 ng/mL, respectively. The results showed that the ATLD-TRTP method was suitable for the determination of ACE in air-pollution source samples even in the presence of uncalibrated interferents.
A new method based on alternating trilinear decomposition assisted three-dimensional room temperature phosphorescence (ATLD-TRTP) was developed for fast quantitative determination of acenaphthene (ACE) contents in samples of air-pollution source. The contents of ACE in air-pollution source samples, such as greasy dirt, oil smoke and flue dust in Loudi city were detected after simple sample pretreatment. Using ATLD algorithm (n=5), the average recoveries of ACE were 90.5%±7.9%, 99.4%±6.1% and 101.4%±10.9%, respectively, the root-mean-square errors of prediction (RMSEP) were 0.25, 0.12 and 0.20 μg/mL, respectively, and the limits of detection (LOD) were 39.2, 18.9 and 31.0 ng/mL, respectively. The results showed that the ATLD-TRTP method was suitable for the determination of ACE in air-pollution source samples even in the presence of uncalibrated interferents.
2018, 46(9): 1446-1454
doi: 10.11895/j.issn.0253-3820.171343
Abstract:
A method for drug discrimination with near infrared spectroscopy based on stacked sparse auto-encoders combined with kernel extreme learning machine (SSAE-KELM) was developed. By introducing the KELM instead of the SSAE's Softmax classification and BP fine-tuning stage, the training steps, training parameters and training time of the SSAE were reduced, and the practical application of the deep learning network was improved, as well the classification ability of the model was improved by introduction of kernel function. Among which SSAE was used to initialize the entire network model and learn useful features from the input data and KELM was used to perform the classification. To identify binary-classification and multi-classification of drugs, the predictability, stability and training time of SSAE-KELM model for the same package (Aluminum-plastic or non-Aluminum-plastic) drug by different manufactures were investigated. At the same time, SSAE-KELM was compared with ELM, SSAE, SVM, BP and Dropout-DBN, and it was found that SSAE-KELM not only reduced the training time but had higher classification accuracy and stability in binary and multi-class classification. Therefore, SSAE-KELM is an effective spectral classification modeling tool.
A method for drug discrimination with near infrared spectroscopy based on stacked sparse auto-encoders combined with kernel extreme learning machine (SSAE-KELM) was developed. By introducing the KELM instead of the SSAE's Softmax classification and BP fine-tuning stage, the training steps, training parameters and training time of the SSAE were reduced, and the practical application of the deep learning network was improved, as well the classification ability of the model was improved by introduction of kernel function. Among which SSAE was used to initialize the entire network model and learn useful features from the input data and KELM was used to perform the classification. To identify binary-classification and multi-classification of drugs, the predictability, stability and training time of SSAE-KELM model for the same package (Aluminum-plastic or non-Aluminum-plastic) drug by different manufactures were investigated. At the same time, SSAE-KELM was compared with ELM, SSAE, SVM, BP and Dropout-DBN, and it was found that SSAE-KELM not only reduced the training time but had higher classification accuracy and stability in binary and multi-class classification. Therefore, SSAE-KELM is an effective spectral classification modeling tool.
2018, 46(9): 1455-1463
doi: 10.11895/j.issn.0253-3820.181337
Abstract:
Graphene oxide (GO) was covalently coupled to the surface of amino silica gel by amide bond. β-Cyclodextrin (β-CD) was further chemically bonded to GO to prepare a novel chiral stationary phase. The resulting material was characterized by Fourier transform-infrared (FT-IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analysis and thermogravimetric analysis (TGA). The separation of seven enantiomers was improved in varying degrees. At the same time, the stationary phase showed typical characteristics of hydrophilic interaction chromatography (HILIC), and four small nucleoside molecules were separated when the mobile phase was methanol-acetonitrile-water (45:45:10, V/V) in HILIC mode. In addition, the separation mechanism of the stationary phase was further explored by studying the effects of mobile phase composition, temperature, and pH on the analyte retention. The low temperature was conducive to the separation of analytes at 20-60℃. The addition of protonated solvent methanol significantly decreased retention time of the four analytes. The pH affected the degree of protonation of the analyte, the interaction among analytes and stationary phase, and retention time of analytes. The results showed that GO and β-CD played a synergistic effect in the chiral resolution of the chromatographic stationary phase. The retention of analytes in HILIC was attributed to their mixed-mode retention mechanisms including hydrophilic interactions, electrostatic interactions, hydrogen bonding, π-π stacking and so on.
Graphene oxide (GO) was covalently coupled to the surface of amino silica gel by amide bond. β-Cyclodextrin (β-CD) was further chemically bonded to GO to prepare a novel chiral stationary phase. The resulting material was characterized by Fourier transform-infrared (FT-IR) spectra, scanning electron microscopy (SEM), transmission electron microscopy (TEM), elemental analysis and thermogravimetric analysis (TGA). The separation of seven enantiomers was improved in varying degrees. At the same time, the stationary phase showed typical characteristics of hydrophilic interaction chromatography (HILIC), and four small nucleoside molecules were separated when the mobile phase was methanol-acetonitrile-water (45:45:10, V/V) in HILIC mode. In addition, the separation mechanism of the stationary phase was further explored by studying the effects of mobile phase composition, temperature, and pH on the analyte retention. The low temperature was conducive to the separation of analytes at 20-60℃. The addition of protonated solvent methanol significantly decreased retention time of the four analytes. The pH affected the degree of protonation of the analyte, the interaction among analytes and stationary phase, and retention time of analytes. The results showed that GO and β-CD played a synergistic effect in the chiral resolution of the chromatographic stationary phase. The retention of analytes in HILIC was attributed to their mixed-mode retention mechanisms including hydrophilic interactions, electrostatic interactions, hydrogen bonding, π-π stacking and so on.
2018, 46(9): 1464-1471
doi: 10.11895/j.issn.0253-3820.181369
Abstract:
Boronate affinity is an important method to extract selectively cis-diol biomolecules. In this work, a novel polymeric brush-type magnetic adsorbent with high density of boronate was successfully prepared. Specifically, polyethyleneimine was firstly employed to supply a large quantity of initiator sites on the surface of the magnetic nanoparticales, and then 3-acrylamidophenylboronic acid (AAPBA) monomer was grafted from the surface of magnetic nanoparticales using surface-initiated atom transfer radical polymerization (SI-ATRP). The mixture of cis-diol and non-cis-diol compounds was extracted by magnetic dispersion solid-phase extraction method, and it was found that the obtained adsorbent showed good selectivity to cis-diol small molecules and biomacromolecules. In addition, the binding capacity was measured by the adsorption isotherm method to be (151±32) mmol/g for catechol, (123±18) mmol/g for adenosine and 1.5 μmol/g for ovalbumin, respectively, which was far higher than those reported in the references. Finally the prepared nanoparticles were employed to extract four nucleosides in urine and glycoproteins in egg white, respectively. The results showed that the nanoparticles could effectively remove some potential interference in biological samples. In addition, the developed method exhibited good recovery for four nucleosides (83.8%-108.7%, RSD<15%) and excellent selectivity for glycoprotein. The adsorbents had potential in selective enrichment of cis-diol compounds from real biological samples.
Boronate affinity is an important method to extract selectively cis-diol biomolecules. In this work, a novel polymeric brush-type magnetic adsorbent with high density of boronate was successfully prepared. Specifically, polyethyleneimine was firstly employed to supply a large quantity of initiator sites on the surface of the magnetic nanoparticales, and then 3-acrylamidophenylboronic acid (AAPBA) monomer was grafted from the surface of magnetic nanoparticales using surface-initiated atom transfer radical polymerization (SI-ATRP). The mixture of cis-diol and non-cis-diol compounds was extracted by magnetic dispersion solid-phase extraction method, and it was found that the obtained adsorbent showed good selectivity to cis-diol small molecules and biomacromolecules. In addition, the binding capacity was measured by the adsorption isotherm method to be (151±32) mmol/g for catechol, (123±18) mmol/g for adenosine and 1.5 μmol/g for ovalbumin, respectively, which was far higher than those reported in the references. Finally the prepared nanoparticles were employed to extract four nucleosides in urine and glycoproteins in egg white, respectively. The results showed that the nanoparticles could effectively remove some potential interference in biological samples. In addition, the developed method exhibited good recovery for four nucleosides (83.8%-108.7%, RSD<15%) and excellent selectivity for glycoprotein. The adsorbents had potential in selective enrichment of cis-diol compounds from real biological samples.
2018, 46(9): 1472-1478
doi: 10.11895/j.issn.0253-3820.181044
Abstract:
Sulfur oxide is one of the most concerned air pollutants. Current detection technique for sulfur oxide is complicated, and in situ techniques are in highly demand. Herein, 3D polymethyl methacylate colloidal arrays which were embedded inside methylcellulose (MC) and carboxymethylcellulose (CMC) membrane were prepared, and then opal and inverse opal cellulose photonic crystal with bright structural color were obtained. After treated with dimethyl sulfoxide (DMSO), the structural color of the inverse opal cellulose photonic crystal turned from red to colorless, and the naked-eye detection for SO2 was achieved with a detection limit of lower than 7898 mg/m3. This technique might be useful for the in situ detection of SO2 pollutant in the air.
Sulfur oxide is one of the most concerned air pollutants. Current detection technique for sulfur oxide is complicated, and in situ techniques are in highly demand. Herein, 3D polymethyl methacylate colloidal arrays which were embedded inside methylcellulose (MC) and carboxymethylcellulose (CMC) membrane were prepared, and then opal and inverse opal cellulose photonic crystal with bright structural color were obtained. After treated with dimethyl sulfoxide (DMSO), the structural color of the inverse opal cellulose photonic crystal turned from red to colorless, and the naked-eye detection for SO2 was achieved with a detection limit of lower than 7898 mg/m3. This technique might be useful for the in situ detection of SO2 pollutant in the air.
2018, 46(9): 1479-1485
doi: 10.11895/j.issn.0253-3820.181253
Abstract:
Plant cells are important biochemical reaction sites for responding to heavy metal stress. Exploring the distribution and speciation of lead (Pb) in celery at the cellular level is an important way to reveal the toxic mechanism of harmful elements on vegetables. In this study, ultrastructural alterations, localization of Pb in root cell and Pb speciation in celery were investigated by energy dispersive transmission electron microscopy (TEM-EDS) and X-ray absorption near edge spectroscopy (XANES). The result showed that Pb stress significantly changed the ultrastructure of celery root cells, increased intercellular spaces, thickened cell walls, and roughened plasma membrane. The roots, stems and leaves of celery had different speciation transformation functions for Pb, which could convert inorganic lead (Pb(NO3)2) into organic lead form. About 62.7% of Pb in celery root cells deposited in the cell wall as the form of Pb5(PO4)3Cl, which showed the tolerance and detoxification of plant for Pb. The organic lead (Pb(Ac)2·3H2O) in roots and stems were approximately from 34.4 to 37.3%, while total organic lead (Pb(C17H35COO)2 and Pb(Ac)2·3H2O) in leaves accounted for 63.3%. This study indicated that Pb-phosphate in plant cells was derived from the biosynthesis by plants rather than the external rhizosphere environment. Pb in the rhizosphere of celery could enter the root cell as the form of Pb-Ac complex, and a part of Pb was converted into Pb5(PO4)3Cl deposition in the cell wall to detoxify and tolerate of Pb, and a small part of Pb was transported to the leaves and accumulated as the form of macromolecular Pb-organic acid and Pb-phosphate.
Plant cells are important biochemical reaction sites for responding to heavy metal stress. Exploring the distribution and speciation of lead (Pb) in celery at the cellular level is an important way to reveal the toxic mechanism of harmful elements on vegetables. In this study, ultrastructural alterations, localization of Pb in root cell and Pb speciation in celery were investigated by energy dispersive transmission electron microscopy (TEM-EDS) and X-ray absorption near edge spectroscopy (XANES). The result showed that Pb stress significantly changed the ultrastructure of celery root cells, increased intercellular spaces, thickened cell walls, and roughened plasma membrane. The roots, stems and leaves of celery had different speciation transformation functions for Pb, which could convert inorganic lead (Pb(NO3)2) into organic lead form. About 62.7% of Pb in celery root cells deposited in the cell wall as the form of Pb5(PO4)3Cl, which showed the tolerance and detoxification of plant for Pb. The organic lead (Pb(Ac)2·3H2O) in roots and stems were approximately from 34.4 to 37.3%, while total organic lead (Pb(C17H35COO)2 and Pb(Ac)2·3H2O) in leaves accounted for 63.3%. This study indicated that Pb-phosphate in plant cells was derived from the biosynthesis by plants rather than the external rhizosphere environment. Pb in the rhizosphere of celery could enter the root cell as the form of Pb-Ac complex, and a part of Pb was converted into Pb5(PO4)3Cl deposition in the cell wall to detoxify and tolerate of Pb, and a small part of Pb was transported to the leaves and accumulated as the form of macromolecular Pb-organic acid and Pb-phosphate.
2018, 46(9): 1486-1492
doi: 10.11895/j.issn.0253-3820.181212
Abstract:
A high capacity anion exchange magnetic absorbent was prepared by immobilization of hyperbranched polyethyleneimine (PEI) on polydopamine-coated Fe3O4 microspheres (Fe3O4@pDA) and the ion exchange capacity was determined as 9.1 mmol/g. The absorbent was characterized by transmission electron microscope (TEM), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). Moreover, the adsorption behavior of the absorbent for protein was carefully investigated by static adsorption using bovine serum albumin (BSA) and β-casein as models and then the static isotherms were determined under the optimum conditions. It was shown that the highest adsorption amount for protein was obtained when the adsorption time was 2 h and the pH was 7.0. Under the optimum conditions, the saturated adsorption capacity towards β-casein and BSA was determined as high as 237.5 and 204.5 μg/mg, respectively. Comparatively, the adsorbent exhibited little adsorption towards lysozyme and Rnase A, showing highly selectivity towards acidic protein. Therefore, the adsorbent exhibited potential in the separation and purification of protein from real samples.
A high capacity anion exchange magnetic absorbent was prepared by immobilization of hyperbranched polyethyleneimine (PEI) on polydopamine-coated Fe3O4 microspheres (Fe3O4@pDA) and the ion exchange capacity was determined as 9.1 mmol/g. The absorbent was characterized by transmission electron microscope (TEM), infrared spectroscopy (IR) and thermogravimetric analysis (TGA). Moreover, the adsorption behavior of the absorbent for protein was carefully investigated by static adsorption using bovine serum albumin (BSA) and β-casein as models and then the static isotherms were determined under the optimum conditions. It was shown that the highest adsorption amount for protein was obtained when the adsorption time was 2 h and the pH was 7.0. Under the optimum conditions, the saturated adsorption capacity towards β-casein and BSA was determined as high as 237.5 and 204.5 μg/mg, respectively. Comparatively, the adsorbent exhibited little adsorption towards lysozyme and Rnase A, showing highly selectivity towards acidic protein. Therefore, the adsorbent exhibited potential in the separation and purification of protein from real samples.
2018, 46(9): 1493-1500
doi: 10.11895/j.issn.0253-3820.181176
Abstract:
A method for determination of seven volatile halogenated hydrocarbons in drinking water by dispersive liquid-liquid microextraction-gas chromatography with electron capture detection was developed. Biphenyl-biphenyl ether mixture, as a non-chlorinated organic solvent, was used as extractant. The extractant could be separated easily by centrifugation because of its high density, and the extraction process could be completed within 3 min. The amount of extractants, types and amount of dispersants, extraction time and extraction temperature were optimized. For the extraction of seven volatile halogenated hydrocarbons from 5.00 mL aqueous sample, 200 μL of extractant and 0.30 mL of methanol as disperser solvent were used, and the extraction equilibrium could be reached within 30 s with a high extraction recovery of over 90%. In addition, the enrichment factor reached a high value of 22.5-24.7. The sediment phase was injected and analyzed by gas chromatography with DB-624 column and detected by electron capture detector. The limit of detection of this method was 0.003-0.032 μg/L based on S/N=3. The linear range for chloroform was from 0.500 μg/L to 100.0 μg/L, for trichloroethylene and bromoform was from 0.100 μg/L to 20.0 μg/L, for perchlormethane, bromodichloromethan, dibromochloromethane and perchloroethylene was from 0.100 μg/L to 10.0 μg/L, while the correlation coefficients (R2) were no less than 0.998. The relative standard deviations of this method were 2.1%-7.6%. At different concentration levels, the relative recoveries ranged from 93.0% to 102.9%.
A method for determination of seven volatile halogenated hydrocarbons in drinking water by dispersive liquid-liquid microextraction-gas chromatography with electron capture detection was developed. Biphenyl-biphenyl ether mixture, as a non-chlorinated organic solvent, was used as extractant. The extractant could be separated easily by centrifugation because of its high density, and the extraction process could be completed within 3 min. The amount of extractants, types and amount of dispersants, extraction time and extraction temperature were optimized. For the extraction of seven volatile halogenated hydrocarbons from 5.00 mL aqueous sample, 200 μL of extractant and 0.30 mL of methanol as disperser solvent were used, and the extraction equilibrium could be reached within 30 s with a high extraction recovery of over 90%. In addition, the enrichment factor reached a high value of 22.5-24.7. The sediment phase was injected and analyzed by gas chromatography with DB-624 column and detected by electron capture detector. The limit of detection of this method was 0.003-0.032 μg/L based on S/N=3. The linear range for chloroform was from 0.500 μg/L to 100.0 μg/L, for trichloroethylene and bromoform was from 0.100 μg/L to 20.0 μg/L, for perchlormethane, bromodichloromethan, dibromochloromethane and perchloroethylene was from 0.100 μg/L to 10.0 μg/L, while the correlation coefficients (R2) were no less than 0.998. The relative standard deviations of this method were 2.1%-7.6%. At different concentration levels, the relative recoveries ranged from 93.0% to 102.9%.
2018, 46(9): 1501-1506
doi: 10.11895/j.issn.0253-3820.171238
Abstract:
In the process of industrial transformation of straw, due to the complicated structural relationship of straw itself, the conversion efficiency is low. Therefore, different pretreatment methods are required to pretreat straw to destroy the inherent structure of the straw and improve its enzymatic efficiency. In this study, the effects of different pretreatments on the microstructure of corn stover were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Moreover, the hydrolysis of different pretreated corn stover with cellulase was studied. It was showed that the surface and structure of corn stover were damaged in some extent in pretreatment. The surface of corn stover pretreated with NaOH collapsed mostly, which showed that the structure of lignocellulose was broken effectively. The pretreated corn stover was analyzed with Fourier transform infrared spectroscopy. It was show that the characteristic peaks of ligin at 1600 and 1510 cm-1 disappeared for corn stover pretreated with NaOH, which indicated that the lignin was removed effectively. The peaks at 1744-1734 cm-1 of pretreated corn stovers (the characteristic peak of C=O), which related to ligin and hemicellulose, reduced in different extent. It was shown that the lignin and hemicellulose were removed with different pretreated methods. Moreover, it was shown that the crystallinities of pretreated corn stovers changed in different extent with X-ray scanning. The crystallinity of corn stover pretreated with H2SO4 got the maxium value of 43.4%. The effects of different pretreated methods were evaluated with corn stover hydrolysis by cellulase. The maxium value of glucose was 33.32 g/L. This study provided basis for the efficient production of biochemicals with different pretreated corn stover.
In the process of industrial transformation of straw, due to the complicated structural relationship of straw itself, the conversion efficiency is low. Therefore, different pretreatment methods are required to pretreat straw to destroy the inherent structure of the straw and improve its enzymatic efficiency. In this study, the effects of different pretreatments on the microstructure of corn stover were investigated by scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR) and X-ray diffraction (XRD). Moreover, the hydrolysis of different pretreated corn stover with cellulase was studied. It was showed that the surface and structure of corn stover were damaged in some extent in pretreatment. The surface of corn stover pretreated with NaOH collapsed mostly, which showed that the structure of lignocellulose was broken effectively. The pretreated corn stover was analyzed with Fourier transform infrared spectroscopy. It was show that the characteristic peaks of ligin at 1600 and 1510 cm-1 disappeared for corn stover pretreated with NaOH, which indicated that the lignin was removed effectively. The peaks at 1744-1734 cm-1 of pretreated corn stovers (the characteristic peak of C=O), which related to ligin and hemicellulose, reduced in different extent. It was shown that the lignin and hemicellulose were removed with different pretreated methods. Moreover, it was shown that the crystallinities of pretreated corn stovers changed in different extent with X-ray scanning. The crystallinity of corn stover pretreated with H2SO4 got the maxium value of 43.4%. The effects of different pretreated methods were evaluated with corn stover hydrolysis by cellulase. The maxium value of glucose was 33.32 g/L. This study provided basis for the efficient production of biochemicals with different pretreated corn stover.
