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2018 Volume 46 Issue 11
2018, 46(11): 1685-1694
doi: 10.11895/j.issn.0253-3820.181462
Abstract:
The electrochemical sensors have been widely applied in the fields of disease diagnosis, environmental monitoring and food safety due to their advantages such as simplicity, rapidity, high sensitivity, low-cost, easy miniaturization and on-line analysis. However, the conventional electrochemical sensors suffer from low stability and poor reproducibility. The ratiometric electrochemical sensors may overcome these issues by adopting a dual-signal mode, i.e., "one-to-two" signal output resulting from two label-redox molecules, which can efficiently overcome the potential interference from the inherent background electrochemical signals and improve the sensitivity and selectivity. In this review, we summarize the principles of ratiometric electrochemical sensors and their applications in sensitive detection of proteins, DNA, small biological molecules and metal ions. Moreover, we give new insight into the future direction and challenges in the development of ratiometric electrochemical sensors.
The electrochemical sensors have been widely applied in the fields of disease diagnosis, environmental monitoring and food safety due to their advantages such as simplicity, rapidity, high sensitivity, low-cost, easy miniaturization and on-line analysis. However, the conventional electrochemical sensors suffer from low stability and poor reproducibility. The ratiometric electrochemical sensors may overcome these issues by adopting a dual-signal mode, i.e., "one-to-two" signal output resulting from two label-redox molecules, which can efficiently overcome the potential interference from the inherent background electrochemical signals and improve the sensitivity and selectivity. In this review, we summarize the principles of ratiometric electrochemical sensors and their applications in sensitive detection of proteins, DNA, small biological molecules and metal ions. Moreover, we give new insight into the future direction and challenges in the development of ratiometric electrochemical sensors.
2018, 46(11): 1695-1702
doi: 10.11895/j.issn.0253-3820.171287
Abstract:
Cell membrane chromatography, which has been used to build an in vitro screening model, has become a practical method to screen active ingredients of traditional Chinese medicine or to study the interaction between drugs and receptors. In this paper, the development of cell membrane chromatography technology and its preparation methods, the optimization of the system and methodological for its stability and other issues were reviewed, as well its unique advantages on selection of active ingredients of traditional Chinese medicine. On this basis, the future development trend of cell membrane chromatography technology was discussed in order to provide ideas for the further development of cell membrane chromatography and its further application in the field of drug high throughput screening.
Cell membrane chromatography, which has been used to build an in vitro screening model, has become a practical method to screen active ingredients of traditional Chinese medicine or to study the interaction between drugs and receptors. In this paper, the development of cell membrane chromatography technology and its preparation methods, the optimization of the system and methodological for its stability and other issues were reviewed, as well its unique advantages on selection of active ingredients of traditional Chinese medicine. On this basis, the future development trend of cell membrane chromatography technology was discussed in order to provide ideas for the further development of cell membrane chromatography and its further application in the field of drug high throughput screening.
2018, 46(11): 1703-1713
doi: 10.11895/j.issn.0253-3820.181509
Abstract:
Over the past decade, ambient mass spectrometry (AMS) has become an important scientific research tool and is widely used in various important fields such as pharmaceuticals, food, environment, public safety, clinic diagnosis and so on. Ambient ionization technology, as the key for AMS analysis, allows the direct sampling/ionization of analytes from raw practical samples without any sample pretreatment, and has greatly improved the analytical efficiency. At present, nearly 100 kinds of different ambient ionization technologies have been developed for the study of complex solid, gaseous, liquid, and even viscous samples. Herein, the ambient ionization methods were introduced by the aspect of energy and charge transfer process, and the new ambient ionization devices developed in the last 5 years were briefly summarized and discussed. Furthermore, the advantages and disadvantages of ambient ionization technology, and the possible development direction of atmospheric ionization technology in the future were prospected.
Over the past decade, ambient mass spectrometry (AMS) has become an important scientific research tool and is widely used in various important fields such as pharmaceuticals, food, environment, public safety, clinic diagnosis and so on. Ambient ionization technology, as the key for AMS analysis, allows the direct sampling/ionization of analytes from raw practical samples without any sample pretreatment, and has greatly improved the analytical efficiency. At present, nearly 100 kinds of different ambient ionization technologies have been developed for the study of complex solid, gaseous, liquid, and even viscous samples. Herein, the ambient ionization methods were introduced by the aspect of energy and charge transfer process, and the new ambient ionization devices developed in the last 5 years were briefly summarized and discussed. Furthermore, the advantages and disadvantages of ambient ionization technology, and the possible development direction of atmospheric ionization technology in the future were prospected.
2018, 46(11): 1714-1723
doi: 10.11895/j.issn.0253-3820.181378
Abstract:
Ultra high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS) combined with multivariate and univariate data analysis methods was used to analyze lipid metabolomics of mitochondria-damaged Saccharomyces cerevisiae (ResD-4) after heavy ion beam radiation. The composition of lipid metabolites in control and ResD-4 was detected, and a total of 648 lipid molecules were identified. The results showed that the orthogonal partial least squares discriminant analysis (OPLS-DA) could accurately distinguish the lipid metabolites of ResD-4 and control. Based on variable importance for the projection (VIP), variation multiple (FC) and difference analysis (p), 12 subfamilies, 54 types of significant difference in lipid molecules were finally screened including diacylglycerol (DG)(16:0/18:1), lysophosphatidylcholine (LPC) (18:1), lysophosphatidylethanolamine (LPE) (16:0), lysophosphatidylinositol (LPI) (18:1), lysophosphatidylserine (LPS) (18:1), phosphatidic acid (PA) (16:0/18:1), phosphatidylcholine (PC) (31:1), phosphatidylethanolamine (PE) (16:0/10:0), phosphatidylinositol (PI) (15:0/18:1), phosphatidylserine (PS) (16:0/16:1), sulfoquinovosyl diacylglycerol (SQDG) (37:4), triglyceride (TG) (15:0/16:0/18:1), etc. Significant differences in the expression level of lipid molecules showed that the expression levels of DG, TG, SQDG, PA, PC, PI, LPC, LPE and LPI were up-regulated, and PE, PS and LPS were down-regulated. The results showed that S. cerevisiae might respond by adjusting the content of lipid components after mitochondrial damage caused by heavy ion beam radiation. The lipid molecules with significant difference expression level may be potential markers for S. cerevisiae mitochondrial damage induced by heavy ion beam radiation.
Ultra high performance liquid chromatography-electrospray ionization-mass spectrometry (UHPLC-ESI-MS) combined with multivariate and univariate data analysis methods was used to analyze lipid metabolomics of mitochondria-damaged Saccharomyces cerevisiae (ResD-4) after heavy ion beam radiation. The composition of lipid metabolites in control and ResD-4 was detected, and a total of 648 lipid molecules were identified. The results showed that the orthogonal partial least squares discriminant analysis (OPLS-DA) could accurately distinguish the lipid metabolites of ResD-4 and control. Based on variable importance for the projection (VIP), variation multiple (FC) and difference analysis (p), 12 subfamilies, 54 types of significant difference in lipid molecules were finally screened including diacylglycerol (DG)(16:0/18:1), lysophosphatidylcholine (LPC) (18:1), lysophosphatidylethanolamine (LPE) (16:0), lysophosphatidylinositol (LPI) (18:1), lysophosphatidylserine (LPS) (18:1), phosphatidic acid (PA) (16:0/18:1), phosphatidylcholine (PC) (31:1), phosphatidylethanolamine (PE) (16:0/10:0), phosphatidylinositol (PI) (15:0/18:1), phosphatidylserine (PS) (16:0/16:1), sulfoquinovosyl diacylglycerol (SQDG) (37:4), triglyceride (TG) (15:0/16:0/18:1), etc. Significant differences in the expression level of lipid molecules showed that the expression levels of DG, TG, SQDG, PA, PC, PI, LPC, LPE and LPI were up-regulated, and PE, PS and LPS were down-regulated. The results showed that S. cerevisiae might respond by adjusting the content of lipid components after mitochondrial damage caused by heavy ion beam radiation. The lipid molecules with significant difference expression level may be potential markers for S. cerevisiae mitochondrial damage induced by heavy ion beam radiation.
2018, 46(11): 1724-1731
doi: 10.11895/j.issn.0253-3820.181318
Abstract:
The protective effect of Ding-Zhi-Xiao-Wan (DZXW) on Aβ25-35 induced PC12 cells was investigated from two aspects of cell apoptosis and oxidative stress. And the formula was decomposed into single herbs and three herbs to clarify the mechanisms of action, compatibility mechanisms and main active ingredients of DZXW. The viability of PC12 cells was evaluated by MTT assay and lactate dehydrogenease content, ginseng and poria cocos played the key roles in enhancing cell viability. Compared with the model group, it could improve the cell viability about 30%. The protection mechanism of DZXW against Aβ25-35 induced PC12 cells injury on oxidative stress and cell apoptosis pathways were studied by flow cytometry, mitochondrial membrane potential (MMP), content of malondialdehyde (MDA) and glutathione (GSH) for the further research. Ginseng and poria could significantly inhibit the cell apoptosis, and also decreased MDA content to reduce the membrane lipid peroxidation. The effect of polygala radix (PR) and acorus tatarinowii rhizoma (ATR) could improve the content of GSH in PC12 cells to inhibit oxidative stress injuries, and the activities of ginseng and poria were improved after the compatibility with PR and ATR. Overall speaking, the compatibility of DZXW formula was scientific rationality.
The protective effect of Ding-Zhi-Xiao-Wan (DZXW) on Aβ25-35 induced PC12 cells was investigated from two aspects of cell apoptosis and oxidative stress. And the formula was decomposed into single herbs and three herbs to clarify the mechanisms of action, compatibility mechanisms and main active ingredients of DZXW. The viability of PC12 cells was evaluated by MTT assay and lactate dehydrogenease content, ginseng and poria cocos played the key roles in enhancing cell viability. Compared with the model group, it could improve the cell viability about 30%. The protection mechanism of DZXW against Aβ25-35 induced PC12 cells injury on oxidative stress and cell apoptosis pathways were studied by flow cytometry, mitochondrial membrane potential (MMP), content of malondialdehyde (MDA) and glutathione (GSH) for the further research. Ginseng and poria could significantly inhibit the cell apoptosis, and also decreased MDA content to reduce the membrane lipid peroxidation. The effect of polygala radix (PR) and acorus tatarinowii rhizoma (ATR) could improve the content of GSH in PC12 cells to inhibit oxidative stress injuries, and the activities of ginseng and poria were improved after the compatibility with PR and ATR. Overall speaking, the compatibility of DZXW formula was scientific rationality.
2018, 46(11): 1732-1738
doi: 10.11895/j.issn.0253-3820.181463
Abstract:
The protein expression profiles of the northeast Chinese Sika deer antler at nascent stage (15 d) and rapid growth stage (60 d) were investigated by using the isotope labeled protein relative and absolute quantification (iTRAQ), liquid chromatography-mass spectrometry and bioinformatics analysis. A total of 127 kinds of differentially expressed proteins were identified. Compared to rapid growth stage, there were 49 kinds of differentially expressed proteins significantly up-regulated at rapid growth stage, and there were 78 kinds of differentially expressed proteins significantly down-regulated. These differentially expressed proteins were mainly extracellular matrix components and involved in the regulation of nerve growth and blood circulation process. Among them, a variety of extracellular matrix proteins were synthesized at nascent stage, however, the expression of these proteins was significantly decreased at rapid growth stage. Meanwhile, the expression of functional proteins involved in the regulation of nerve growth and blood circulation was significantly up-regulated. These differentially expressed proteins coordinated to regulate the growth rate of Sika deer antler. The results provide the basic data for further revealing the growth mechanism, and important guiding for the clinical application.
The protein expression profiles of the northeast Chinese Sika deer antler at nascent stage (15 d) and rapid growth stage (60 d) were investigated by using the isotope labeled protein relative and absolute quantification (iTRAQ), liquid chromatography-mass spectrometry and bioinformatics analysis. A total of 127 kinds of differentially expressed proteins were identified. Compared to rapid growth stage, there were 49 kinds of differentially expressed proteins significantly up-regulated at rapid growth stage, and there were 78 kinds of differentially expressed proteins significantly down-regulated. These differentially expressed proteins were mainly extracellular matrix components and involved in the regulation of nerve growth and blood circulation process. Among them, a variety of extracellular matrix proteins were synthesized at nascent stage, however, the expression of these proteins was significantly decreased at rapid growth stage. Meanwhile, the expression of functional proteins involved in the regulation of nerve growth and blood circulation was significantly up-regulated. These differentially expressed proteins coordinated to regulate the growth rate of Sika deer antler. The results provide the basic data for further revealing the growth mechanism, and important guiding for the clinical application.
2018, 46(11): 1739-1747
doi: 10.11895/j.issn.0253-3820.171442
Abstract:
With nitroaniline and 8-hydroxy-2-methylquinoline as the raw materials, an intermediate of 2-hydroxy-5-(4-nitroazobenzene) benzaldehyde was prepared for synthesizing 2-[2-hydroxy-5-(4-nitroazobenzene) styryl]-8-hydroxyquinoline by microwave reaction in acetic anhydride. An azo conjugate structure was formed by connecting the quinoline ring and the benzene ring with the double bond and azo in the probe molecule. The hydroxyl and nitrogen atoms provided good anion recognition sites that could selectively recognize F-, AcO- and OH- ion through hydrogen bonding in the probe. The probe could formed a 1:1 complex with F- and AcO- respectively, and the ratio of absorbance at 595 nm and 350 nm (A595 nm/A350 nm) was related to the concentration of F- and AcO- with the color change from yellowish to deep blue in CH3CN/DMSO (99:1, V/V). The binding force of probe with F- decreased significantly, and the intensity of characteristic absorption peak fell sharply because of the proton effect. However, the combination of the probe and AcO- was almost impervious, and only the maximum absorption wavelength shifted purple. Therefore the probe could be used to monitor AcO- with the ratiometric detection of absorbance value at 560 nm and 350 nm (A560 nm/A350 nm) in CH3CN/H2O/DMSO (94:5:1, V/V) medium. The detection of F- and AcO- could be realized separately on the basis of solvent effect and wavelength resolution. Within pH 6-10, due to the protonation of hydroxyl in the probe, the ratio of absorption value at 355 nm and 600 nm (A355 nm/A600 nm) of probe was related to the pH value, and with the concentration increase of OH-, the color of the solution changed from light yellow to blue in DMSO/H2O (9:1, V/V) medium. A plot of the absorbance intensity as a function of pH afforded a calculated pKa value of 7.65. A visible, rapid and sensitive visual method for detection of trace amount of F-, AcO- and pH was developed on the basis of the obvious color change.
With nitroaniline and 8-hydroxy-2-methylquinoline as the raw materials, an intermediate of 2-hydroxy-5-(4-nitroazobenzene) benzaldehyde was prepared for synthesizing 2-[2-hydroxy-5-(4-nitroazobenzene) styryl]-8-hydroxyquinoline by microwave reaction in acetic anhydride. An azo conjugate structure was formed by connecting the quinoline ring and the benzene ring with the double bond and azo in the probe molecule. The hydroxyl and nitrogen atoms provided good anion recognition sites that could selectively recognize F-, AcO- and OH- ion through hydrogen bonding in the probe. The probe could formed a 1:1 complex with F- and AcO- respectively, and the ratio of absorbance at 595 nm and 350 nm (A595 nm/A350 nm) was related to the concentration of F- and AcO- with the color change from yellowish to deep blue in CH3CN/DMSO (99:1, V/V). The binding force of probe with F- decreased significantly, and the intensity of characteristic absorption peak fell sharply because of the proton effect. However, the combination of the probe and AcO- was almost impervious, and only the maximum absorption wavelength shifted purple. Therefore the probe could be used to monitor AcO- with the ratiometric detection of absorbance value at 560 nm and 350 nm (A560 nm/A350 nm) in CH3CN/H2O/DMSO (94:5:1, V/V) medium. The detection of F- and AcO- could be realized separately on the basis of solvent effect and wavelength resolution. Within pH 6-10, due to the protonation of hydroxyl in the probe, the ratio of absorption value at 355 nm and 600 nm (A355 nm/A600 nm) of probe was related to the pH value, and with the concentration increase of OH-, the color of the solution changed from light yellow to blue in DMSO/H2O (9:1, V/V) medium. A plot of the absorbance intensity as a function of pH afforded a calculated pKa value of 7.65. A visible, rapid and sensitive visual method for detection of trace amount of F-, AcO- and pH was developed on the basis of the obvious color change.
2018, 46(11): 1748-1754
doi: 10.11895/j.issn.0253-3820.171426
Abstract:
Bi2O3@graphene material, fabricated by hydrothermal and self-assembly technology, was used to modify glassy carbon electrode. In this way, the electrochemical reaction activity sites were increased due to high specific surface area, and the pore structure of graphene sheet was favorable of electron transfer. Based on this, a new method for simultaneous determination of trace Pb2+ and Cd2+ was established by using anodic stripping voltammetry. The anodic stripping voltammetry response exhibited linear relationship with concentrations of Pb2+ and Cd2+ in the ranges of 10-200 μg/L and 25-200 μg/L, respectively. The detection limits were 0.02 μg/L and 0.25 μg/L for Pb2+ and Cd2+, respectively, with a deposition time of 120 s. The Bi2O3@graphene-modified glass carbon electrode exhibited high sensitivity, selectivity and stability, and were applied to determine Cd2+ and Pb2+ in real waste water samples, and the results were consistent with those determination results of inductively coupled plasmon-atomic emission spectrometry, indicating the good potential of Bi2O3-modified electrode in detection of trace heavy metal ions.
Bi2O3@graphene material, fabricated by hydrothermal and self-assembly technology, was used to modify glassy carbon electrode. In this way, the electrochemical reaction activity sites were increased due to high specific surface area, and the pore structure of graphene sheet was favorable of electron transfer. Based on this, a new method for simultaneous determination of trace Pb2+ and Cd2+ was established by using anodic stripping voltammetry. The anodic stripping voltammetry response exhibited linear relationship with concentrations of Pb2+ and Cd2+ in the ranges of 10-200 μg/L and 25-200 μg/L, respectively. The detection limits were 0.02 μg/L and 0.25 μg/L for Pb2+ and Cd2+, respectively, with a deposition time of 120 s. The Bi2O3@graphene-modified glass carbon electrode exhibited high sensitivity, selectivity and stability, and were applied to determine Cd2+ and Pb2+ in real waste water samples, and the results were consistent with those determination results of inductively coupled plasmon-atomic emission spectrometry, indicating the good potential of Bi2O3-modified electrode in detection of trace heavy metal ions.
2018, 46(11): 1755-1762
doi: 10.11895/j.issn.0253-3820.181272
Abstract:
The total content of oxygen-containing organic compounds (OCOCs) in middle/low temperature coal tar (M/LTCT) are relatively high. Many OCOCs in M/LTCT are value-added organic compounds. In this investigation, a gas chromatograph-mass spectrometer (GC-MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (NIESIFTICRMS) were used to analyze OCOCs in a M/LTCT from Northern Shaanxi, aiming at understanding the composition and structures of the OCOCs to provide scientific basis for efficiently separating the OCOCs. The results showed that one oxygen-containing species (O1, most of which are arenols) and two oxygen-containing species (O2) in the GC-MS-detectable OCOCs accounted for 99.4% and 0.6%, respectively; numbers of carbon, oxygen and aromatic rings in the OCOCs detected with the NIESIFTICRMS were 8-35, 1-5 and 1-4, respectively, and O1 and O2 were predominantly abundant among the OCOCs; the main acidic OCOCs were phenol, benzenediols, benzoic acid and their alkyl-substitutes along with cyclanoic and chain alkanoic acids, and the main species were arenols with 1-4 aromatic rings among O1. GC-MS and NIESIFTICRMS have complementary advantages, and are proved to be effective tools for understanding the composition and structures of OCOCs in M/LTCT at molecular level.
The total content of oxygen-containing organic compounds (OCOCs) in middle/low temperature coal tar (M/LTCT) are relatively high. Many OCOCs in M/LTCT are value-added organic compounds. In this investigation, a gas chromatograph-mass spectrometer (GC-MS) and negative-ion electrospray ionization Fourier transform ion cyclotron resonance mass spectrometer (NIESIFTICRMS) were used to analyze OCOCs in a M/LTCT from Northern Shaanxi, aiming at understanding the composition and structures of the OCOCs to provide scientific basis for efficiently separating the OCOCs. The results showed that one oxygen-containing species (O1, most of which are arenols) and two oxygen-containing species (O2) in the GC-MS-detectable OCOCs accounted for 99.4% and 0.6%, respectively; numbers of carbon, oxygen and aromatic rings in the OCOCs detected with the NIESIFTICRMS were 8-35, 1-5 and 1-4, respectively, and O1 and O2 were predominantly abundant among the OCOCs; the main acidic OCOCs were phenol, benzenediols, benzoic acid and their alkyl-substitutes along with cyclanoic and chain alkanoic acids, and the main species were arenols with 1-4 aromatic rings among O1. GC-MS and NIESIFTICRMS have complementary advantages, and are proved to be effective tools for understanding the composition and structures of OCOCs in M/LTCT at molecular level.
2018, 46(11): 1763-1769
doi: 10.11895/j.issn.0253-3820.181281
Abstract:
Quorum sensing (QS) is a intercellular communication phenomenon among most bacteria which allows bacteria to monitor and respond their local environment and population density by secreting and sensing certain signal molecules. Pseudomonas aeruginosa (PAE) is one of main opportunistic pathogenic bacteria for wound infection and strong resistance to antibiotics because of the formation of biofilm. Recently, some research groups have reported that the formation of PAE biofilm is mainly controlled by QS mechanism, which relies on the release and recognition of specific low molecular weight molecules (so-called quorum sensing signal molecule, QSSM). Therefore, it is desirable to develop a rapid and sensitive method for the detection of both PAE and its corresponding QSSM to improve the cure of wound infections. In this work, poly(oligo(ethylene glycol) methacrylate) (POEGMA) brushes on Si wafer were prepared by atomic transfer radical polymerization technique (ATRP), which were then employed as matrix for the loading of silver nanoparticles (AgNP) by repeating the immersion-rinsing-drying steps, giving rise to a POEGMA/AgNP nanocomposite SERS substrate. Scanning electron microscopy (SEM) and UV-Visible spectroscopy measurements clearly indicated the 3D distribution of AgNPs within the POEGMA brush. The resulting SERS substrates were then used for the detection of PAE and two typical QSSMs:pyocyanin (PCN) and N-dodecanoyl-homoserine lactone (C12-HSL). Raman measurements suggested that the detection limit of the current SERS substrate for PCN, C12-HSL and PAE was 10-10 mol/L, 10-8 mol/L and 10 CFU/mL, respectively. Considering the merits associated with SERS technique, such as label-free, highly sensitive and low interference from water, the current POEGMA/AgNP nanocomposite SERS substrate is highly potential for the future investigation of PAE's quorum sensing phenomenon.
Quorum sensing (QS) is a intercellular communication phenomenon among most bacteria which allows bacteria to monitor and respond their local environment and population density by secreting and sensing certain signal molecules. Pseudomonas aeruginosa (PAE) is one of main opportunistic pathogenic bacteria for wound infection and strong resistance to antibiotics because of the formation of biofilm. Recently, some research groups have reported that the formation of PAE biofilm is mainly controlled by QS mechanism, which relies on the release and recognition of specific low molecular weight molecules (so-called quorum sensing signal molecule, QSSM). Therefore, it is desirable to develop a rapid and sensitive method for the detection of both PAE and its corresponding QSSM to improve the cure of wound infections. In this work, poly(oligo(ethylene glycol) methacrylate) (POEGMA) brushes on Si wafer were prepared by atomic transfer radical polymerization technique (ATRP), which were then employed as matrix for the loading of silver nanoparticles (AgNP) by repeating the immersion-rinsing-drying steps, giving rise to a POEGMA/AgNP nanocomposite SERS substrate. Scanning electron microscopy (SEM) and UV-Visible spectroscopy measurements clearly indicated the 3D distribution of AgNPs within the POEGMA brush. The resulting SERS substrates were then used for the detection of PAE and two typical QSSMs:pyocyanin (PCN) and N-dodecanoyl-homoserine lactone (C12-HSL). Raman measurements suggested that the detection limit of the current SERS substrate for PCN, C12-HSL and PAE was 10-10 mol/L, 10-8 mol/L and 10 CFU/mL, respectively. Considering the merits associated with SERS technique, such as label-free, highly sensitive and low interference from water, the current POEGMA/AgNP nanocomposite SERS substrate is highly potential for the future investigation of PAE's quorum sensing phenomenon.
2018, 46(11): 1770-1777
doi: 10.11895/j.issn.0253-3820.181269
Abstract:
A novel strategy based on DNA induced conformation change was developed by rendering the imprinting cavity with refined structure in order to further improve the selectivity of molecular imprinting technology. The double-stranded DNA (dsDNA) was first self-assembled on the surface of the gold electrode, then the cimaterol molecule, taken as the representative target, was bound with the groove of dsDNA to form the complex template, together with which the molecular imprinting polymer (MIPs) was prepared by electropolymerization in the monomer solution. After elution of cimaterol, the obtained MIPs sensor had a remarkably high selectivity toward cimaterol. The combination process of cimetaerol and DNA was studied by UV-Vis and it was found to be the groove combination model. The optimum conditions of the system were optimized by electrochemical method. The results showed that when using ethanol-acetic acid (8:1, V/V) as an eluent, with the elution time of 35 min and rebound time of 45 min, the sensor showed the best recognition ability toward cimaterol. This sensor exhibited a linear detection range of 1.0×10-13-1.0×10-10 mol/L, with the detection limit of 3.2×10-14 mol/L. The sensor was successfully applied to cimaterol detection in pork samples.
A novel strategy based on DNA induced conformation change was developed by rendering the imprinting cavity with refined structure in order to further improve the selectivity of molecular imprinting technology. The double-stranded DNA (dsDNA) was first self-assembled on the surface of the gold electrode, then the cimaterol molecule, taken as the representative target, was bound with the groove of dsDNA to form the complex template, together with which the molecular imprinting polymer (MIPs) was prepared by electropolymerization in the monomer solution. After elution of cimaterol, the obtained MIPs sensor had a remarkably high selectivity toward cimaterol. The combination process of cimetaerol and DNA was studied by UV-Vis and it was found to be the groove combination model. The optimum conditions of the system were optimized by electrochemical method. The results showed that when using ethanol-acetic acid (8:1, V/V) as an eluent, with the elution time of 35 min and rebound time of 45 min, the sensor showed the best recognition ability toward cimaterol. This sensor exhibited a linear detection range of 1.0×10-13-1.0×10-10 mol/L, with the detection limit of 3.2×10-14 mol/L. The sensor was successfully applied to cimaterol detection in pork samples.
2018, 46(11): 1778-1784
doi: 10.11895/j.issn.0253-3820.181351
Abstract:
A method for separation of epoxiconazole enantiomers was established by reversed-phase high performance liquid chromatography (HPLC) on a Lux Cellulose-1 chiral column. The elution order of the epoxiconazole enantiomers was determined by HPLC coupled with a circular dichroism (CD) detector. The absolute configuration of epoxiconazole enantiomer was determined through comparison of experimental and predicted ECD spectra. Based on this, a simple and reliable method for simultaneous determination of epoxiconazole enantiomers in fruits and vegetables samples was established, and the method was systematically evaluated by the precision, accuracy, sensitivity and matrix effect of sample. When using acetonitrile-water (60:40, V/V) as mobile phase with a flow rate of 0.6 mL/min, the epoxiconazole enantiomers were baseline separated at 30℃ and detection wavelength of 220 nm. The first peak eluted from the Lux Cellulose-1 chiral column was confirmed to be (S,R)-(-)-epoxiconazole and the second peak was (R,S)-(+)-epoxiconazole. Excellent linearity of enantiomers was observed within concentration range of 0.1-10 mg/L, and there was no matrix effect. The results of the standard addition experiment showed that the average recovery of epoxiconazole enantiomers in the six matrices was 80.8%-96.7%, with inter-day precision (Relative standard deviation, RSD) of 1.5%-6.1% and intra-day RSD of 1.1%-6.7%. The limits of quantification (LOQs) for two enantiomers in six matrices were 0.05 mg/kg, whereas the limits of detection (LODs) were 0.10-0.15 ng. The analytical method could meet the requirement of simultaneous determination of epoxiconazole enantiomers in food and environmental sampless
A method for separation of epoxiconazole enantiomers was established by reversed-phase high performance liquid chromatography (HPLC) on a Lux Cellulose-1 chiral column. The elution order of the epoxiconazole enantiomers was determined by HPLC coupled with a circular dichroism (CD) detector. The absolute configuration of epoxiconazole enantiomer was determined through comparison of experimental and predicted ECD spectra. Based on this, a simple and reliable method for simultaneous determination of epoxiconazole enantiomers in fruits and vegetables samples was established, and the method was systematically evaluated by the precision, accuracy, sensitivity and matrix effect of sample. When using acetonitrile-water (60:40, V/V) as mobile phase with a flow rate of 0.6 mL/min, the epoxiconazole enantiomers were baseline separated at 30℃ and detection wavelength of 220 nm. The first peak eluted from the Lux Cellulose-1 chiral column was confirmed to be (S,R)-(-)-epoxiconazole and the second peak was (R,S)-(+)-epoxiconazole. Excellent linearity of enantiomers was observed within concentration range of 0.1-10 mg/L, and there was no matrix effect. The results of the standard addition experiment showed that the average recovery of epoxiconazole enantiomers in the six matrices was 80.8%-96.7%, with inter-day precision (Relative standard deviation, RSD) of 1.5%-6.1% and intra-day RSD of 1.1%-6.7%. The limits of quantification (LOQs) for two enantiomers in six matrices were 0.05 mg/kg, whereas the limits of detection (LODs) were 0.10-0.15 ng. The analytical method could meet the requirement of simultaneous determination of epoxiconazole enantiomers in food and environmental sampless
2018, 46(11): 1785-1793
doi: 10.11895/j.issn.0253-3820.181467
Abstract:
Sensor array was used to rapidly evaluate the composition and content of volatile organic compounds (VOCs) in tobacco package materials. Abstract odor factor maps (AOFMs) extracted from signal data of sensor array were used as characteristic map of samples, and then similarity measure was implemented to evaluate VOCs in samples. By using this method, 8 types of packing paper samples with different VOCs and 2 types of packing paper samples with similar composition and content of VOCs were determined. As comparisons, principal component analysis (PCA) only discriminated 2 types of samples and parallel factor analysis (PARAFAC) discriminated 6 samples. Hence, similarity measurement of AOFMs provided higher recognition accuracy than the other two methods. The advantages of this method were in three aspects, basing on a correct signal model targeted to sensor array, employing an objective and well-defined evaluation standard, and using standard deviation of samples' signal data to assist evaluation.
Sensor array was used to rapidly evaluate the composition and content of volatile organic compounds (VOCs) in tobacco package materials. Abstract odor factor maps (AOFMs) extracted from signal data of sensor array were used as characteristic map of samples, and then similarity measure was implemented to evaluate VOCs in samples. By using this method, 8 types of packing paper samples with different VOCs and 2 types of packing paper samples with similar composition and content of VOCs were determined. As comparisons, principal component analysis (PCA) only discriminated 2 types of samples and parallel factor analysis (PARAFAC) discriminated 6 samples. Hence, similarity measurement of AOFMs provided higher recognition accuracy than the other two methods. The advantages of this method were in three aspects, basing on a correct signal model targeted to sensor array, employing an objective and well-defined evaluation standard, and using standard deviation of samples' signal data to assist evaluation.
2018, 46(11): 1794-1801
doi: 10.11895/j.issn.0253-3820.181197
Abstract:
Metal-organic framework materials (MOFs), formed by the coordination of inorganic metal ions and organic ligands, are a kind of new materials with porous network structure. MOFs possess many advantages such as a large specific surface area, developed pores, easy functionalization, and good stability. In the present, MOFs have been applied to many areas including solar batteries, biopharmaceuticals, catalysis and biosensors. But little attentions have been received on the application of MOFs as the sensing materials for analytical detection platform based on ion-selective electrodes. In this work, copper-based metal-organic frameworks (CuMOFs) with porous spherical structure were used as the sensitive carriers of ion-selective electrode, in which multi-walled carbon nanotubes (MWCNTs) with excellent conductivity and large surface area were doped. This resulted in the development of a sensitive solid carbon paste electrode for the detection of silver ion (Ag+). The experimental results demonstrated that the CuMOFs-based solid electrode had good selective potential response to Ag+. We investigated the effect of different content ratio of the sensing membrane CuMOFs and MWCNTS, and pH of the tested solution on the potential response. The obtained results suggested that the proposed solid carbon paste electrode containing CuMOFs and MWCNTs (99:1, w/w) had the best near-Nernst potential response to Ag+ in HNO3 solution at pH 2.0, suggesting that MWCNTs was favorable for promoting the electron transfer in the electrode interface. Under the optimal experimental conditions, the widest dynamic linear range was 5.0 μmol/L-0.1 mol/L with the slope of 57.9 mV/dec and the detection limit of 3.2 μmol/L. This may be attributed to the effective interaction between CuMOFs and Ag+, which was proved by the UV-Vis spectra before and after CuMOFs interacted with Ag+. Furthermore, the solid ion-selective electrode displayed high selectivity for silver ions in the presence of other tested interfering ions, good stability, and fast and reversible potential response in different concentrations of Ag+ solution (20-40 s). Compared with other reported Ag+-selective electrodes based on other sensing carriers, the analytical sensitivity of MWCNTs-doped-CuMOFs solid carbon paste electrode were obviously improved. The developed electrode was preliminarily applied to the quantitative determination of Ag+ in the actual water samples collected from laboratory and lake, and the recoveries were satisfactory. This work is promising and potential to further extend the application of other MOFs in chemical sensors.
Metal-organic framework materials (MOFs), formed by the coordination of inorganic metal ions and organic ligands, are a kind of new materials with porous network structure. MOFs possess many advantages such as a large specific surface area, developed pores, easy functionalization, and good stability. In the present, MOFs have been applied to many areas including solar batteries, biopharmaceuticals, catalysis and biosensors. But little attentions have been received on the application of MOFs as the sensing materials for analytical detection platform based on ion-selective electrodes. In this work, copper-based metal-organic frameworks (CuMOFs) with porous spherical structure were used as the sensitive carriers of ion-selective electrode, in which multi-walled carbon nanotubes (MWCNTs) with excellent conductivity and large surface area were doped. This resulted in the development of a sensitive solid carbon paste electrode for the detection of silver ion (Ag+). The experimental results demonstrated that the CuMOFs-based solid electrode had good selective potential response to Ag+. We investigated the effect of different content ratio of the sensing membrane CuMOFs and MWCNTS, and pH of the tested solution on the potential response. The obtained results suggested that the proposed solid carbon paste electrode containing CuMOFs and MWCNTs (99:1, w/w) had the best near-Nernst potential response to Ag+ in HNO3 solution at pH 2.0, suggesting that MWCNTs was favorable for promoting the electron transfer in the electrode interface. Under the optimal experimental conditions, the widest dynamic linear range was 5.0 μmol/L-0.1 mol/L with the slope of 57.9 mV/dec and the detection limit of 3.2 μmol/L. This may be attributed to the effective interaction between CuMOFs and Ag+, which was proved by the UV-Vis spectra before and after CuMOFs interacted with Ag+. Furthermore, the solid ion-selective electrode displayed high selectivity for silver ions in the presence of other tested interfering ions, good stability, and fast and reversible potential response in different concentrations of Ag+ solution (20-40 s). Compared with other reported Ag+-selective electrodes based on other sensing carriers, the analytical sensitivity of MWCNTs-doped-CuMOFs solid carbon paste electrode were obviously improved. The developed electrode was preliminarily applied to the quantitative determination of Ag+ in the actual water samples collected from laboratory and lake, and the recoveries were satisfactory. This work is promising and potential to further extend the application of other MOFs in chemical sensors.
2018, 46(11): 1802-1807
doi: 10.11895/j.issn.0253-3820.171101
Abstract:
Coffee and coffee drinks are products preferred by a number of consumers in their daily life. However, it is lack of viable methods for identification of natural coffee source. A new method of liquid chromatography coupled to isotope ratio mass spectrometry (LC-IRMS) was developed for determination of caffeine δ13C value for discrimination of natural and synthetic caffeine source in the coffee drinks. Caffeine in samples was separated by reversed-phase liquid chromatography with An XBridge Shild PR C18 (2.1 mm×50 mm, 3.5 μm). The column temperature was 50℃ and the water flow rate was 400 μL/min. Target analytes were converted to CO2 in the oxidation reactor of the LC-IsoLink interface. Finally the caffeine δ13C value was directly detected with a Delta V Advantage isotope ratio mass spectrometer. On the basis of the carbon isotope analysis of 44 coffee soybean samples by LC-IRMS, it was concluded that there was one distinguishable group of δ13C-values:-25.3‰ to -30.9‰ in natural coffee soybean. The average of δ13C-values (δaverage) was -27.9 ‰, and the standard deviation (s) was 1.3‰. The samples were discriminated for unnatural coffee soybean source, when the caffeine δ13C-value was less than or approached δaverage-3s (-31.7‰). This method was applied to identify the caffeine source in 16 kinds of coffee drinks, in which one sample was discriminated to have unnatural coffee soybean source.
Coffee and coffee drinks are products preferred by a number of consumers in their daily life. However, it is lack of viable methods for identification of natural coffee source. A new method of liquid chromatography coupled to isotope ratio mass spectrometry (LC-IRMS) was developed for determination of caffeine δ13C value for discrimination of natural and synthetic caffeine source in the coffee drinks. Caffeine in samples was separated by reversed-phase liquid chromatography with An XBridge Shild PR C18 (2.1 mm×50 mm, 3.5 μm). The column temperature was 50℃ and the water flow rate was 400 μL/min. Target analytes were converted to CO2 in the oxidation reactor of the LC-IsoLink interface. Finally the caffeine δ13C value was directly detected with a Delta V Advantage isotope ratio mass spectrometer. On the basis of the carbon isotope analysis of 44 coffee soybean samples by LC-IRMS, it was concluded that there was one distinguishable group of δ13C-values:-25.3‰ to -30.9‰ in natural coffee soybean. The average of δ13C-values (δaverage) was -27.9 ‰, and the standard deviation (s) was 1.3‰. The samples were discriminated for unnatural coffee soybean source, when the caffeine δ13C-value was less than or approached δaverage-3s (-31.7‰). This method was applied to identify the caffeine source in 16 kinds of coffee drinks, in which one sample was discriminated to have unnatural coffee soybean source.
2018, 46(11): 1808-1813
doi: 10.11895/j.issn.0253-3820.171035
Abstract:
A method for detection of newly synthesized protein via metabolic incorporation of non-natural amino acid was developed, in which Raw264.7 cells were treated by lipopolysaccharide (LPS) to generate tumor necrosis factor alpha (TNF-α). Experimental parameters including the concentration of LPS and the duration of LPS treatment were investigated by measuring the LPS stimulated TNF-α from Raw264.7 cells. The optimal experimental conditions were determined as follows. Raw264.7 cells were cultured in Met-free DMEM containing 1% fetal bovine serum (FBS), and then treated for 4 h with LPS at concentration of 10 ng/mL in presence of AHA. The biotin tags were introduced into proteins containing azidohomoalanine (AHA) by copper-catalyzed alkyne-azidecycloaddition (CuAAC). Then TNF-α was specifically captured by the antibody adsorbed on the solid support, on which the biotin tag could be detected by streptavidin coupled with horseradish peroxidase (HRP). This study provided a method for the detection of a specific newly synthesized protein, and characterization of specific protein turnover.
A method for detection of newly synthesized protein via metabolic incorporation of non-natural amino acid was developed, in which Raw264.7 cells were treated by lipopolysaccharide (LPS) to generate tumor necrosis factor alpha (TNF-α). Experimental parameters including the concentration of LPS and the duration of LPS treatment were investigated by measuring the LPS stimulated TNF-α from Raw264.7 cells. The optimal experimental conditions were determined as follows. Raw264.7 cells were cultured in Met-free DMEM containing 1% fetal bovine serum (FBS), and then treated for 4 h with LPS at concentration of 10 ng/mL in presence of AHA. The biotin tags were introduced into proteins containing azidohomoalanine (AHA) by copper-catalyzed alkyne-azidecycloaddition (CuAAC). Then TNF-α was specifically captured by the antibody adsorbed on the solid support, on which the biotin tag could be detected by streptavidin coupled with horseradish peroxidase (HRP). This study provided a method for the detection of a specific newly synthesized protein, and characterization of specific protein turnover.
2018, 46(11): 1814-1820
doi: 10.11895/j.issn.0253-3820.181036
Abstract:
Linear ion trap is one hotspot in research of mass spectrometry at present, and a number of linear ion traps with novel structure have been developed so far. To improve the performance of linear ion traps and expand the application, a novel linear ion trap featuring octa-electrodes (OeLIT) was built, which was composed of eight identical columnar electrodes and two end electrodes. This work used the bevel shaped electrodes as an example to investigate mass analysis performance and realize ion directional ejection of OeLIT by applying specific unbalanced RF voltage. The relationship between RF voltage difference ratio (Δ) and internal electric field distribution was studied by software PAN33, and the mass spectra were achieved by AXSIM. It was turned out that the optimal mass resolution of OeLIT at m/z=610 was 3660 when RF voltage difference ratio Δ was 40%. Compared with the performance of triangular-electrode linear ion trap (TeLIT), this result was improved up to 40%. The maximum efficiency of ion unidirectional ejection was up to 91% at Δ=30%.
Linear ion trap is one hotspot in research of mass spectrometry at present, and a number of linear ion traps with novel structure have been developed so far. To improve the performance of linear ion traps and expand the application, a novel linear ion trap featuring octa-electrodes (OeLIT) was built, which was composed of eight identical columnar electrodes and two end electrodes. This work used the bevel shaped electrodes as an example to investigate mass analysis performance and realize ion directional ejection of OeLIT by applying specific unbalanced RF voltage. The relationship between RF voltage difference ratio (Δ) and internal electric field distribution was studied by software PAN33, and the mass spectra were achieved by AXSIM. It was turned out that the optimal mass resolution of OeLIT at m/z=610 was 3660 when RF voltage difference ratio Δ was 40%. Compared with the performance of triangular-electrode linear ion trap (TeLIT), this result was improved up to 40%. The maximum efficiency of ion unidirectional ejection was up to 91% at Δ=30%.
2018, 46(11): 1821-1828
doi: 10.11895/j.issn.0253-3820.181364
Abstract:
A new analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) precursor ion scan (PIS) was developed for the non-target screening of halogenated organic compounds (HOCs). Briefly, fragmented halogen ions from the precursor of HOCs could pass Q3 channels fixing at m/z 35, 37, 79, 81 and 127, and the corresponding precursors were simultaneously recorded in Q1. Therefore, the halogenated species and molecular ions of HOCs could be inferred from the selection of Q3 and Q1. Results showed that PIS had a higher sensitivity to HOCs when the collision energy in Q2 was set at 50 eV. Bernoulli experiment models were used to calculate theoretical isotopic abundances of HOCs. This method was successfully applied to the screening of HOCs in laboratory reaction samples and seawater. This work suggested that PIS was potentially an effective tool for the non-target screening of HOCs in various environmental matrices.
A new analytical method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) precursor ion scan (PIS) was developed for the non-target screening of halogenated organic compounds (HOCs). Briefly, fragmented halogen ions from the precursor of HOCs could pass Q3 channels fixing at m/z 35, 37, 79, 81 and 127, and the corresponding precursors were simultaneously recorded in Q1. Therefore, the halogenated species and molecular ions of HOCs could be inferred from the selection of Q3 and Q1. Results showed that PIS had a higher sensitivity to HOCs when the collision energy in Q2 was set at 50 eV. Bernoulli experiment models were used to calculate theoretical isotopic abundances of HOCs. This method was successfully applied to the screening of HOCs in laboratory reaction samples and seawater. This work suggested that PIS was potentially an effective tool for the non-target screening of HOCs in various environmental matrices.
2018, 46(11): 1829-1835
doi: 10.11895/j.issn.0253-3820.181395
Abstract:
A new diffusive gradient in thin films sampling method (DGT) with a CeO2/ZrO2 mixed binding gel was developed for measurement of As(Ⅲ) and As(Ⅴ) in water and sediment. New CeO2/ZrO2 binding gel showed efficient adsorption toward As(Ⅲ) and As(Ⅴ) and was better than CeO2 gel and ZrO2 gels. The effective capacities of CeO2/ZrO2-DGT for As(Ⅲ) and As(Ⅴ) were 77.8 μg and 58.1 μg per device, respectively. Solution pH and ionic strength had no effects on the uptake of As(Ⅲ) and As(Ⅴ) by CeO2/ZrO2-DGT. The masses of As(Ⅲ) and As(Ⅴ) accumulated by the DGT increased linearly with time (R2>0.99) up to 72 h for tap water and synthetic seawater samples. Limits of detection (LODs) of As(Ⅲ) and As(Ⅴ) by CeO2/ZrO2-DGT coupled with an on-line hydride generation atomic fluorescence spectrometry (HG-AFS) were 0.06 μg/L and 0.08 μg/L, respectively. The method was used for measuring As(Ⅲ) and As(Ⅴ) in surface and sediment of several reservoirs in Dalian. The measured concentrations of As(Ⅲ) and As(Ⅴ) were 0.13-0.14 μg/L and 0.20-0.25 μg/L in the surface water and 0.38-1.82 μg/L and 0.69-3.46 μg/L in sediment.
A new diffusive gradient in thin films sampling method (DGT) with a CeO2/ZrO2 mixed binding gel was developed for measurement of As(Ⅲ) and As(Ⅴ) in water and sediment. New CeO2/ZrO2 binding gel showed efficient adsorption toward As(Ⅲ) and As(Ⅴ) and was better than CeO2 gel and ZrO2 gels. The effective capacities of CeO2/ZrO2-DGT for As(Ⅲ) and As(Ⅴ) were 77.8 μg and 58.1 μg per device, respectively. Solution pH and ionic strength had no effects on the uptake of As(Ⅲ) and As(Ⅴ) by CeO2/ZrO2-DGT. The masses of As(Ⅲ) and As(Ⅴ) accumulated by the DGT increased linearly with time (R2>0.99) up to 72 h for tap water and synthetic seawater samples. Limits of detection (LODs) of As(Ⅲ) and As(Ⅴ) by CeO2/ZrO2-DGT coupled with an on-line hydride generation atomic fluorescence spectrometry (HG-AFS) were 0.06 μg/L and 0.08 μg/L, respectively. The method was used for measuring As(Ⅲ) and As(Ⅴ) in surface and sediment of several reservoirs in Dalian. The measured concentrations of As(Ⅲ) and As(Ⅴ) were 0.13-0.14 μg/L and 0.20-0.25 μg/L in the surface water and 0.38-1.82 μg/L and 0.69-3.46 μg/L in sediment.
2018, 46(11): 1836-1844
doi: 10.11895/j.issn.0253-3820.181341
Abstract:
A novel chromium (Ⅲ) ion-imprinted material (Cr(Ⅲ)-ⅡPs) was prepared by the surface imprinted technique with Cr(Ⅲ) ion as the template, di(2-pyridyl)methanol as functional monomer, 3-(triethoxysilyl)-propyl-iodine as cross-linking agent and mesoporous silica MCM-41 as solid supports. The structure and morphology of Cr(Ⅲ)-ⅡPs and NIP were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, small angle X-ray diffraction, scanning electron microscopy, transmission electron microscope and N2 adsorption-desorption analysis. The BET test results showed that the specific surface area (625.3 m2/g) of Cr(Ⅲ)-ⅡPs was greater than that of NIP (527.1 m2/g). When the temperature was 25℃, pH=5 and the adsorption time was 30 min, the adsorption of Cr3+ ions on the imprinted material reached an equilibrium and the adsorption capacity was 151.2 mg/g. The isothermal adsorption model and adsorption kinetics study showed that the adsorption isotherm model conformed to Langmuir model. The model had a correlation coefficient of 0.9929. The adsorption kinetics followed the pseudo-second-order model and the correlation coefficient was 0.9806. The relative selectivity coefficients of Cr(Ⅲ)-ⅡPs for Cr3+/Cr6+, Cr3+/Cu2+, Cr3+/Cd2+, Cr3+/Hg2+, Cr3+/Co2+, Cr3+/Ni2+ were 5.13, 1.21, 1.97, 1.71, 1.27 and 4.00, showing that Cr(Ⅲ)-ⅡPs had strong selectivity for Cr3+ ions. After regeneration for ten times, the adsorption capacity of Cr(Ⅲ)-ⅡPs remained at 90.7%. The Cr(Ⅲ)-ⅡPs showed good selectivity, reusability and stability.
A novel chromium (Ⅲ) ion-imprinted material (Cr(Ⅲ)-ⅡPs) was prepared by the surface imprinted technique with Cr(Ⅲ) ion as the template, di(2-pyridyl)methanol as functional monomer, 3-(triethoxysilyl)-propyl-iodine as cross-linking agent and mesoporous silica MCM-41 as solid supports. The structure and morphology of Cr(Ⅲ)-ⅡPs and NIP were characterized by Fourier transform infrared spectroscopy, nuclear magnetic resonance, small angle X-ray diffraction, scanning electron microscopy, transmission electron microscope and N2 adsorption-desorption analysis. The BET test results showed that the specific surface area (625.3 m2/g) of Cr(Ⅲ)-ⅡPs was greater than that of NIP (527.1 m2/g). When the temperature was 25℃, pH=5 and the adsorption time was 30 min, the adsorption of Cr3+ ions on the imprinted material reached an equilibrium and the adsorption capacity was 151.2 mg/g. The isothermal adsorption model and adsorption kinetics study showed that the adsorption isotherm model conformed to Langmuir model. The model had a correlation coefficient of 0.9929. The adsorption kinetics followed the pseudo-second-order model and the correlation coefficient was 0.9806. The relative selectivity coefficients of Cr(Ⅲ)-ⅡPs for Cr3+/Cr6+, Cr3+/Cu2+, Cr3+/Cd2+, Cr3+/Hg2+, Cr3+/Co2+, Cr3+/Ni2+ were 5.13, 1.21, 1.97, 1.71, 1.27 and 4.00, showing that Cr(Ⅲ)-ⅡPs had strong selectivity for Cr3+ ions. After regeneration for ten times, the adsorption capacity of Cr(Ⅲ)-ⅡPs remained at 90.7%. The Cr(Ⅲ)-ⅡPs showed good selectivity, reusability and stability.
2018, 46(11): 1845-1850
doi: 10.11895/j.issn.0253-3820.171081
Abstract:
Soybean water is a common sizing agent that is used in the restoration of Chinese paintings and calligraphies. Heating soybean water leads to denaturation of soy protein and thus alters the hydrophobicity of paper after sizing. In this work, the change of surface hydrophobicity of soybean protein in the heating process was analyzed by 8-aniline-1-naphthlene sulfonic acid (ANS) fluorescence probe. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was adopted to sort out different protein contents which later were identified by LC-MS/MS. The self-deconvolution and second derivative curve fitting techniques of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to analyze the change of secondary structures of soybean protein at different heating temperatures. ANS fluorescence probe experiment showed that the soybean water achieved its largest hydrophobicity when the temperature was 80℃. The results of SDS-PAGE and LC-MS/MS revealed the disappearance of globulin glycinin G3 and glycoprotein lectin at high temperature. ATR-FTIR analysis showed that the increase of heating temperature of soybean water raised β-sheet content from 41.14% to 48.87% and the original α-helix, β-turn and γ-random structures shifted to β-sheet structure. There was a positive correlation between the structural content of β-sheet and the surface hydrophobicity. The research showed that the heating temperature of soybean milk at 80℃ was suitable for calligraphy and painting restoration.
Soybean water is a common sizing agent that is used in the restoration of Chinese paintings and calligraphies. Heating soybean water leads to denaturation of soy protein and thus alters the hydrophobicity of paper after sizing. In this work, the change of surface hydrophobicity of soybean protein in the heating process was analyzed by 8-aniline-1-naphthlene sulfonic acid (ANS) fluorescence probe. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) was adopted to sort out different protein contents which later were identified by LC-MS/MS. The self-deconvolution and second derivative curve fitting techniques of attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to analyze the change of secondary structures of soybean protein at different heating temperatures. ANS fluorescence probe experiment showed that the soybean water achieved its largest hydrophobicity when the temperature was 80℃. The results of SDS-PAGE and LC-MS/MS revealed the disappearance of globulin glycinin G3 and glycoprotein lectin at high temperature. ATR-FTIR analysis showed that the increase of heating temperature of soybean water raised β-sheet content from 41.14% to 48.87% and the original α-helix, β-turn and γ-random structures shifted to β-sheet structure. There was a positive correlation between the structural content of β-sheet and the surface hydrophobicity. The research showed that the heating temperature of soybean milk at 80℃ was suitable for calligraphy and painting restoration.
