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2021 Volume 49 Issue 11
2021, 49(11): 1767-1778
doi: 10.19756/j.issn.0253-3820.210481
Abstract:
Electrochemical analysis has been widely used in the field of highly sensitive detection of bioactive molecules and gases, but the controllable preparation of high-performance electrode materials has always been challenging. Atomic layer deposition can realize the precise preparation of thin film materials and nanomaterials through continuous self-restricted semi-reactions, and provides a novel, simple, and precise method for the controllable preparation of high-performance electrode materials for electroanalysis. This paper first summarizes the principles and characteristics of atomic layer deposition, and then focuses on the application progresses of atomic layer deposition in the field of electrochemical detection of biomolecules and gas molecules. In addition, the application perspectives of atomic layer deposition in the field of electroanalytical chemistry are proposed.
Electrochemical analysis has been widely used in the field of highly sensitive detection of bioactive molecules and gases, but the controllable preparation of high-performance electrode materials has always been challenging. Atomic layer deposition can realize the precise preparation of thin film materials and nanomaterials through continuous self-restricted semi-reactions, and provides a novel, simple, and precise method for the controllable preparation of high-performance electrode materials for electroanalysis. This paper first summarizes the principles and characteristics of atomic layer deposition, and then focuses on the application progresses of atomic layer deposition in the field of electrochemical detection of biomolecules and gas molecules. In addition, the application perspectives of atomic layer deposition in the field of electroanalytical chemistry are proposed.
2021, 49(11): 1779-1791
doi: 10.19756/j.issn.0253-3820.210636
Abstract:
Due to the heterogeneity between different cells, the analysis of metabolites at single cell level can provide abundant information for the study of complex biological systems.Microfluidic systems can manipulate fluids in microscale structures that are close to the size of cells, making microfluidic systems suitable for single-cell analysis. In this review, current single-cell metabolite analysis technology based on microfluidic systems was introduced. Various microfluidic single-cell metabolite analysis systems based on different detection techniques including fluorescence microscopic imaging, laser induced fluorescence, electrochemistry, mass spectrometry, chemiluminescence, sensor detection technology, as well as their applications were reviewed.
Due to the heterogeneity between different cells, the analysis of metabolites at single cell level can provide abundant information for the study of complex biological systems.Microfluidic systems can manipulate fluids in microscale structures that are close to the size of cells, making microfluidic systems suitable for single-cell analysis. In this review, current single-cell metabolite analysis technology based on microfluidic systems was introduced. Various microfluidic single-cell metabolite analysis systems based on different detection techniques including fluorescence microscopic imaging, laser induced fluorescence, electrochemistry, mass spectrometry, chemiluminescence, sensor detection technology, as well as their applications were reviewed.
2021, 49(11): 1792-1803
doi: 10.19756/j.issn.0253-3820.201455
Abstract:
Aristolochic acids (AAs) are a kind of nitrophenanthrene compound in Aristolochiaceae plants. AAs are classified as the Class I carcinogen by the International Agency for Research on Cancer because of their irreversible nephrotoxicity. The analysis of AAs is of great significance for exploring the pathogenic mechanism and preventing from AAs nephropathy (AAN), Balkan endemic nephropathy (BEN) and chronic kidney disease (CKD). The present article summarizes and compares the common methods for detection of AAs, specifically focusing on the applications and the latest advances of high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The existential problems, the challenges, and the further development of the detection of AAs are fully discussed.
Aristolochic acids (AAs) are a kind of nitrophenanthrene compound in Aristolochiaceae plants. AAs are classified as the Class I carcinogen by the International Agency for Research on Cancer because of their irreversible nephrotoxicity. The analysis of AAs is of great significance for exploring the pathogenic mechanism and preventing from AAs nephropathy (AAN), Balkan endemic nephropathy (BEN) and chronic kidney disease (CKD). The present article summarizes and compares the common methods for detection of AAs, specifically focusing on the applications and the latest advances of high performance liquid chromatography (HPLC) and liquid chromatography-mass spectrometry (LC-MS). The existential problems, the challenges, and the further development of the detection of AAs are fully discussed.
2021, 49(11): 1804-1815
doi: 10.19756/j.issn.0253-3820.210654
Abstract:
Alkaline phosphatase (ALP), which can catalyze the dephosphorylation of various phosphorylated species, is an essential enzyme in a variety of mammalian tissues. The exploration of novel approaches for detection of ALP with high selectivity and sensitivity and intracellular imaging in living organisms is of vital importance in human health, clinical diagnosis and environmental analysis. With the development of fluorescent probes, many advantages for ALP detection, such as simple operation, non-invasive, in-situ detection, real-time imaging and so on, have been gradually highlighted. The fluorescent methods are categorized by different response mechanisms for ALP activity sensing:difference in the fluorescence between the phosphorylated substrate and corresponding product; the interaction of certain metal ions and phosphorylated substrates; the in-situ fluorogenic reaction drived by the ALP-enabled dephosphorylation process; inner filter effect; the fluorescence energy transfer system and so on. In this review, we focused on the research progresses of the fluorescent methods in detection of ALP in recent years. Furthermore, the prospects of ALP in the near future were also discussed.
Alkaline phosphatase (ALP), which can catalyze the dephosphorylation of various phosphorylated species, is an essential enzyme in a variety of mammalian tissues. The exploration of novel approaches for detection of ALP with high selectivity and sensitivity and intracellular imaging in living organisms is of vital importance in human health, clinical diagnosis and environmental analysis. With the development of fluorescent probes, many advantages for ALP detection, such as simple operation, non-invasive, in-situ detection, real-time imaging and so on, have been gradually highlighted. The fluorescent methods are categorized by different response mechanisms for ALP activity sensing:difference in the fluorescence between the phosphorylated substrate and corresponding product; the interaction of certain metal ions and phosphorylated substrates; the in-situ fluorogenic reaction drived by the ALP-enabled dephosphorylation process; inner filter effect; the fluorescence energy transfer system and so on. In this review, we focused on the research progresses of the fluorescent methods in detection of ALP in recent years. Furthermore, the prospects of ALP in the near future were also discussed.
2021, 49(11): 1816-1823
doi: 10.19756/j.issn.0253-3820.210470
Abstract:
A micro helium ionization detector (μHID) with counter-intake structure was designed and fabricated by micro-electro-mechanical system (MEMS) technology. The flow field simulation demonstrated that this counter-intake structure brought a "quasi-zero velocity" zone with high gas pressure between excitation electrodes pairs, which contained stable helium with high density, and it was beneficial to excite and stabilize the helium plasma to reduce the baseline noise caused by plasma shaking. The test results of the fabricated μHID demonstrated that stable helium plasma was excited in the "quasi-zero velocity" zone with high gas pressure caused by counter-intake structure, which was consistent with the transient plasma simulation. The baseline noise was below 6 μV. This micro helium ionization detector was successfully used for detection of methylbenzene and ethylbenzene at volume concentration of 0.0001%, showing a low detection limit.
A micro helium ionization detector (μHID) with counter-intake structure was designed and fabricated by micro-electro-mechanical system (MEMS) technology. The flow field simulation demonstrated that this counter-intake structure brought a "quasi-zero velocity" zone with high gas pressure between excitation electrodes pairs, which contained stable helium with high density, and it was beneficial to excite and stabilize the helium plasma to reduce the baseline noise caused by plasma shaking. The test results of the fabricated μHID demonstrated that stable helium plasma was excited in the "quasi-zero velocity" zone with high gas pressure caused by counter-intake structure, which was consistent with the transient plasma simulation. The baseline noise was below 6 μV. This micro helium ionization detector was successfully used for detection of methylbenzene and ethylbenzene at volume concentration of 0.0001%, showing a low detection limit.
Adenosine-stabilized Copper Nanocluster as Fluorescent Probe for Detection of Au(Ⅲ) Ion and Cysteine
2021, 49(11): 1824-1833
doi: 10.19756/j.issn.0253-3820.210619
Abstract:
A fluorescent "turn-off-on" sensor was constructed for detection of Au(Ⅲ) ions and cysteine on the basis of fluorescence quenching of adenosine-stabilized copper nanocluster by Au(Ⅲ) ions and cysteine-induced fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(Ⅲ) system. The adenosine-stabilized copper nanocluster-based sensor gave a linear range of 0.05-10 μmol/L with detection limit of 0.02 μmol/L, and the adenosine-stabilized copper nanocluster/Au(Ⅲ)-based sensor provided a linear range of 5-60 μmol/L with detection limit of 1.6 μmol/L. In addition, the results showed that the fluorescence quenching of adenosine-stabilized copper nanocluster by Au(Ⅲ) ion was mainly originated from the super amplification static quenching effect, and the fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(Ⅲ) by cysteine mainly arose from the complex reaction between cysteine and Au(Ⅲ) and the removal of Au(Ⅲ) on the adenosine-stabilized copper nanocluster/Au(Ⅲ) system. Additionally, the fluorescence sensor for Au(Ⅲ) ions and cysteine possessed high selectivity, and could be successfully used for detection of Au(Ⅲ) ions in water samples and cysteine in pharmaceutical preparations.
A fluorescent "turn-off-on" sensor was constructed for detection of Au(Ⅲ) ions and cysteine on the basis of fluorescence quenching of adenosine-stabilized copper nanocluster by Au(Ⅲ) ions and cysteine-induced fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(Ⅲ) system. The adenosine-stabilized copper nanocluster-based sensor gave a linear range of 0.05-10 μmol/L with detection limit of 0.02 μmol/L, and the adenosine-stabilized copper nanocluster/Au(Ⅲ)-based sensor provided a linear range of 5-60 μmol/L with detection limit of 1.6 μmol/L. In addition, the results showed that the fluorescence quenching of adenosine-stabilized copper nanocluster by Au(Ⅲ) ion was mainly originated from the super amplification static quenching effect, and the fluorescence enhancement of the adenosine-stabilized copper nanocluster/Au(Ⅲ) by cysteine mainly arose from the complex reaction between cysteine and Au(Ⅲ) and the removal of Au(Ⅲ) on the adenosine-stabilized copper nanocluster/Au(Ⅲ) system. Additionally, the fluorescence sensor for Au(Ⅲ) ions and cysteine possessed high selectivity, and could be successfully used for detection of Au(Ⅲ) ions in water samples and cysteine in pharmaceutical preparations.
2021, 49(11): 1834-1844
doi: 10.19756/j.issn.0253-3820.211095
Abstract:
An electrochemical biosensor based on gold nanoflower (GNF) and metal organic framework (MOF) immobilized acetylcholinesterase (AChE) was constructed and used for highly sensitive detection of glyphosate. Firstly, Nafion-Teflon polymer film was formed on glassy carbon electrode (GCE), and GNF with good dispersion was obtained by electrodeposition. Then p-aminothiophenol (4-ATP) was self-assembled on the surface of GNF, and then AChE was immobilized on the electrode by the interaction of amide bond with 4-ATP. Finally, MOF was formed by electropolymerization in a solution containing AChE and 4-ATP functionalized gold nanoparticles (Au@4-ATP), and more AChE was immobilized to prepare AChE sensor (MOF/AChE/GNF/GCE). The biocatalytic activity of the sensor was investigated, and glyphosate was indirectly determined by voltammetry according to the inhibitory effect of glyphosate on the hydrolysis of thioacetylcholine iodide catalyzed by AChE. The logarithm of glyphosate concentration in the range of 5.0×10-16-1.0×10-10 mol/L exhibited a good linear relationship with the current response of differential pulse voltammetry (DPV), and the detection limit was 1.3×10-16 mol/L (S/N=3). The results showed that the method overcame the deficiencies of low enzyme loading, easy aggregation, poor activity, and poor conductivity of MOF itself when conventional MOF was used to immobilize enzymes, and had extremely high sensitivity. The sensor was used for determination of glyphosate in vegetables.
An electrochemical biosensor based on gold nanoflower (GNF) and metal organic framework (MOF) immobilized acetylcholinesterase (AChE) was constructed and used for highly sensitive detection of glyphosate. Firstly, Nafion-Teflon polymer film was formed on glassy carbon electrode (GCE), and GNF with good dispersion was obtained by electrodeposition. Then p-aminothiophenol (4-ATP) was self-assembled on the surface of GNF, and then AChE was immobilized on the electrode by the interaction of amide bond with 4-ATP. Finally, MOF was formed by electropolymerization in a solution containing AChE and 4-ATP functionalized gold nanoparticles (Au@4-ATP), and more AChE was immobilized to prepare AChE sensor (MOF/AChE/GNF/GCE). The biocatalytic activity of the sensor was investigated, and glyphosate was indirectly determined by voltammetry according to the inhibitory effect of glyphosate on the hydrolysis of thioacetylcholine iodide catalyzed by AChE. The logarithm of glyphosate concentration in the range of 5.0×10-16-1.0×10-10 mol/L exhibited a good linear relationship with the current response of differential pulse voltammetry (DPV), and the detection limit was 1.3×10-16 mol/L (S/N=3). The results showed that the method overcame the deficiencies of low enzyme loading, easy aggregation, poor activity, and poor conductivity of MOF itself when conventional MOF was used to immobilize enzymes, and had extremely high sensitivity. The sensor was used for determination of glyphosate in vegetables.
2021, 49(11): 1845-1854
doi: 10.19756/j.issn.0253-3820.210449
Abstract:
Hydrogen sulfide (H2S) plays crucial roles in various physiological process and daily life. However, excess H2S is very harmful to health. Therefore, it is necessary to design a sensitive method for H2S detection.In this work, a novel colorimetric probe 5,5,9,9-tetramethyl-3-(4-nitrophenyl)-2,4,5,6,7,8,9,9a-octahydro-5a,8-methanobenzo[g]indazole (BN) for naked-eye detection of H2S was developed with longifolene derivative isolongifolenone as the starting material. This probe had great merits including rapid response time (0.4 min), high sensitivity (detection limit of 0.31 μmol/L), and high selectivity for H2S detection. The sensing mechanism was confirmed by 1H NMR and HRMS. The experiment results showed that the -NO2 group was reduced into -NH2 group by H2S, and the hydrogen atom on the indazole ring disappeared as soon as probe BN contacted with H2S. The photophysical properties of probe BN toward H2S were examined by density functional theory calculation. Additionally, the probe BN could be loaded on filter paper and was successfully applied to detection of H2S in environmental water samples.
Hydrogen sulfide (H2S) plays crucial roles in various physiological process and daily life. However, excess H2S is very harmful to health. Therefore, it is necessary to design a sensitive method for H2S detection.In this work, a novel colorimetric probe 5,5,9,9-tetramethyl-3-(4-nitrophenyl)-2,4,5,6,7,8,9,9a-octahydro-5a,8-methanobenzo[g]indazole (BN) for naked-eye detection of H2S was developed with longifolene derivative isolongifolenone as the starting material. This probe had great merits including rapid response time (0.4 min), high sensitivity (detection limit of 0.31 μmol/L), and high selectivity for H2S detection. The sensing mechanism was confirmed by 1H NMR and HRMS. The experiment results showed that the -NO2 group was reduced into -NH2 group by H2S, and the hydrogen atom on the indazole ring disappeared as soon as probe BN contacted with H2S. The photophysical properties of probe BN toward H2S were examined by density functional theory calculation. Additionally, the probe BN could be loaded on filter paper and was successfully applied to detection of H2S in environmental water samples.
2021, 49(11): 1855-1863
doi: 10.19756/j.issn.0253-3820.210506
Abstract:
Stimuli-responsiveness of nanoreactors offers a good opportunity for designing site-specific therapeutic agents to maximize the therapeutic efficacy and minimize the side effect. In this work, a dual-enzyme reactor with zinc peroxide-mesoporous silica core-shell structure was constructed for pH-responsive gene therapy and chemodynamic therapy of cancer. The ZnO2@FcDMSN@DNAzyme/GOx (ZFDG) nanoreactors were fabricated by modifying ferrocene (Fc) on the surface of mesoporous silica-coated zinc peroxide nanoparticles, followed by electrostatic adsorption of DNAzyme and glucose oxidase (GOx) in the outer pore structures. After internalization into tumor cells, intracellular acidic environment spurred the release of Zn2+ to activate DNAzyme, leading to the cleavage of the target mRNA for downregulation of early growth factor-1 (EGR-1) and consequent inhibition of tumor cell growth. In addition, GOx could transform abundant intracellular glucose into gluconic acid and hydrogen peroxide (H2O2), which increased the acidity in cells and provided massive substrates for Fenton reaction. The results showed that the presented ZFDG nanoreactors could be degraded under acidic environment and produced Zn2+, which further triggered gene therapy to reduce cell viability down to 70%. Upon combination with enhanced chemodynamic therapy, the cell survival rate could be further lowered to 20% when the concentration of nanoreactor was 50 μg/mL. Therefore, the collaboration of precisely triggered gene therapy and enhanced chemodynamic therapy synchronously improved the treatment efficiency and provided a potential tool for effective cancer therapy.
Stimuli-responsiveness of nanoreactors offers a good opportunity for designing site-specific therapeutic agents to maximize the therapeutic efficacy and minimize the side effect. In this work, a dual-enzyme reactor with zinc peroxide-mesoporous silica core-shell structure was constructed for pH-responsive gene therapy and chemodynamic therapy of cancer. The ZnO2@FcDMSN@DNAzyme/GOx (ZFDG) nanoreactors were fabricated by modifying ferrocene (Fc) on the surface of mesoporous silica-coated zinc peroxide nanoparticles, followed by electrostatic adsorption of DNAzyme and glucose oxidase (GOx) in the outer pore structures. After internalization into tumor cells, intracellular acidic environment spurred the release of Zn2+ to activate DNAzyme, leading to the cleavage of the target mRNA for downregulation of early growth factor-1 (EGR-1) and consequent inhibition of tumor cell growth. In addition, GOx could transform abundant intracellular glucose into gluconic acid and hydrogen peroxide (H2O2), which increased the acidity in cells and provided massive substrates for Fenton reaction. The results showed that the presented ZFDG nanoreactors could be degraded under acidic environment and produced Zn2+, which further triggered gene therapy to reduce cell viability down to 70%. Upon combination with enhanced chemodynamic therapy, the cell survival rate could be further lowered to 20% when the concentration of nanoreactor was 50 μg/mL. Therefore, the collaboration of precisely triggered gene therapy and enhanced chemodynamic therapy synchronously improved the treatment efficiency and provided a potential tool for effective cancer therapy.
2021, 49(11): 1864-1872
doi: 10.19756/j.issn.0253-3820.210497
Abstract:
A non-targeted metabolomics study based on ultra-high performance liquid chromatography qexactive mass spectrometry (UHPLC-QE-MS) for investigation of the variability of metabolites of goat milk across latitudes from Heilongjiang, Gansu and Hunan province of China was performed. The expression trends of 22 differential metabolites were found to be positively correlated with latitude, and 15 differential metabolites were found to be negatively correlated with latitude. The types of differential metabolites whose expression was up-regulated with increasing latitude included glycerophospholipids and sphingolipids. The types of down-regulated differential metabolites included organosulfides, amino acids, organic heterocyclic compounds, alcohols, phenols, organic oxides and organic acids and their derivatives. Metabolic pathway analysis of the differentially expressed metabolites showed that a total of 6 metabolic pathways were involved in the up-regulated differentially expressed metabolites and 7 metabolic pathways were involved in the down-regulated differentially expressed metabolites. This study further mapped the correlation analysis of key metabolic pathways and analyzed the mechanism of interactions between metabolic pathways. This study provided a new perspective to further investigate the influencing factors of sheep milk composition.
A non-targeted metabolomics study based on ultra-high performance liquid chromatography qexactive mass spectrometry (UHPLC-QE-MS) for investigation of the variability of metabolites of goat milk across latitudes from Heilongjiang, Gansu and Hunan province of China was performed. The expression trends of 22 differential metabolites were found to be positively correlated with latitude, and 15 differential metabolites were found to be negatively correlated with latitude. The types of differential metabolites whose expression was up-regulated with increasing latitude included glycerophospholipids and sphingolipids. The types of down-regulated differential metabolites included organosulfides, amino acids, organic heterocyclic compounds, alcohols, phenols, organic oxides and organic acids and their derivatives. Metabolic pathway analysis of the differentially expressed metabolites showed that a total of 6 metabolic pathways were involved in the up-regulated differentially expressed metabolites and 7 metabolic pathways were involved in the down-regulated differentially expressed metabolites. This study further mapped the correlation analysis of key metabolic pathways and analyzed the mechanism of interactions between metabolic pathways. This study provided a new perspective to further investigate the influencing factors of sheep milk composition.
2021, 49(11): 1873-1880
doi: 10.19756/j.issn.0253-3820.210437
Abstract:
With the increasingly urgent need of human health, the sensing devices for toxic and harmful gases monitoring are becoming more and more important. Among them, the detection of triethylamine (TEA) is of great significance for human health, environmental protection and food safety, which puts forward a great challenge on sensing materials with high sensitivity and excellent stability. Herein, polypyrrole (PPy) aerogel was prepared by the room temperature standing method. The as-prepared PPy aerogel materials showed many advantages such as environmental friendliness, reliable repeatability, good selectivity and ease to be synthesized. The results of scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) pore size distribution analyzing showed that the PPy aerogel materials contained a variety of pore structures, which was conducive to its good sensing performance for TEA. The PPy aerogel sensor showed an extremely fast response to TEA (the response time was about 70 s), which was even better than that of many high temperature sensors. At the same time, the senor had a sensitive response to TEA, which was manifested in linear sensibility (10-100 μL/L) and low limit of detection (60 nL/L). The response of the sensor (ΔR/Ra) toward 100 μL/L TEA was about 26%. In brief, the PPy aerogel senor realized quantitative detection of TEA, which was helpful for its application in environmental detection and food safety analysis.
With the increasingly urgent need of human health, the sensing devices for toxic and harmful gases monitoring are becoming more and more important. Among them, the detection of triethylamine (TEA) is of great significance for human health, environmental protection and food safety, which puts forward a great challenge on sensing materials with high sensitivity and excellent stability. Herein, polypyrrole (PPy) aerogel was prepared by the room temperature standing method. The as-prepared PPy aerogel materials showed many advantages such as environmental friendliness, reliable repeatability, good selectivity and ease to be synthesized. The results of scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) pore size distribution analyzing showed that the PPy aerogel materials contained a variety of pore structures, which was conducive to its good sensing performance for TEA. The PPy aerogel sensor showed an extremely fast response to TEA (the response time was about 70 s), which was even better than that of many high temperature sensors. At the same time, the senor had a sensitive response to TEA, which was manifested in linear sensibility (10-100 μL/L) and low limit of detection (60 nL/L). The response of the sensor (ΔR/Ra) toward 100 μL/L TEA was about 26%. In brief, the PPy aerogel senor realized quantitative detection of TEA, which was helpful for its application in environmental detection and food safety analysis.
2021, 49(11): 1881-1889
doi: 10.19756/j.issn.0253-3820.201729
Abstract:
The interaction of human islet amyloid polypeptide (hIAPP) with five kinds of flavonols (Astragalin, isoquercitrin, isorhamnetin-3-O-neohesperidoside, isorhamnetin-3-O-rutinoside, rutin) was investigated by electrospray ionization-ion mobility-mass spectrometry (ESI-IM-MS) and fluorescence spectroscopy. The results showed that the glycosyl groups and hydroxyl groups of aglycones in flavonols could improve their binding affinity with hIAPP, and enhance the gas phase stability of the complexes formed by hIAPP and ligands. However, the effects of multiple hydroxyl groups of aglycones on IAPP aggregation was more obvious, followed by the number of glycosyl groups and different types of glycosyl groups. Among the five flavonols, the complexes formed by rutin and hIAPP were the most stable and rutin had the strong inhibitory action on the fibrillation of hIAPP. IM-MS analysis results showed that rutin could stabilize the conformation of hIAPP by binding to hIAPP. The obtained results were useful to understand the structure-activity of the interaction of flavonols with hIAPP and provide valuable reference for the screening of potent amyloid inhibitors from natural products.
The interaction of human islet amyloid polypeptide (hIAPP) with five kinds of flavonols (Astragalin, isoquercitrin, isorhamnetin-3-O-neohesperidoside, isorhamnetin-3-O-rutinoside, rutin) was investigated by electrospray ionization-ion mobility-mass spectrometry (ESI-IM-MS) and fluorescence spectroscopy. The results showed that the glycosyl groups and hydroxyl groups of aglycones in flavonols could improve their binding affinity with hIAPP, and enhance the gas phase stability of the complexes formed by hIAPP and ligands. However, the effects of multiple hydroxyl groups of aglycones on IAPP aggregation was more obvious, followed by the number of glycosyl groups and different types of glycosyl groups. Among the five flavonols, the complexes formed by rutin and hIAPP were the most stable and rutin had the strong inhibitory action on the fibrillation of hIAPP. IM-MS analysis results showed that rutin could stabilize the conformation of hIAPP by binding to hIAPP. The obtained results were useful to understand the structure-activity of the interaction of flavonols with hIAPP and provide valuable reference for the screening of potent amyloid inhibitors from natural products.
2021, 49(11): 1890-1896
doi: 10.19756/j.issn.0253-3820.201618
Abstract:
The analysis of degree of aging paper is an important research topic in the field of identification of physical evidence. The rule of the structure and composition in aging paper of People's daily from 1966 to 2015 were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray crystal diffraction, scanning electron microscope (SEM), atomic force microscope (AFM) and ion chromatography in this work. The result of FTIR showed that the characteristic peaks of -OH (3000-3600 cm-1), -C-H (2925-3000 cm-1) got weak in the ageing process, which indicated the intramolecular and intermolecular forces of cellulose weakening gradually. The result of X-ray crystal diffraction showed that the crystallinity of paper decreased from 80.6% in 2015 to 71.2% in 1966. The structure of paper in 2015 was neat and smooth according to the results of SEM. SEM was used to observe the surface of paper and found that the microstructure of paper gradually broke and sunken as time. The result of AFM showed that the fiber structure on the surface of paper was gradually fragmented in the aging process. The contents of potassium ion, sodium ion, phosphate ion and chloride ion in paper of different ages were determined by ion chromatography, and found thatthe content of sodium ion decreased gradually, while the contents of other ions increased in the ageing process. The experimental results showed that the micro-structure and composition of newspaper changed regularly with the prolongation of storage time, which could provide evidence for the identification of aging paper.
The analysis of degree of aging paper is an important research topic in the field of identification of physical evidence. The rule of the structure and composition in aging paper of People's daily from 1966 to 2015 were investigated by Fourier transform infrared spectroscopy (FTIR), X-ray crystal diffraction, scanning electron microscope (SEM), atomic force microscope (AFM) and ion chromatography in this work. The result of FTIR showed that the characteristic peaks of -OH (3000-3600 cm-1), -C-H (2925-3000 cm-1) got weak in the ageing process, which indicated the intramolecular and intermolecular forces of cellulose weakening gradually. The result of X-ray crystal diffraction showed that the crystallinity of paper decreased from 80.6% in 2015 to 71.2% in 1966. The structure of paper in 2015 was neat and smooth according to the results of SEM. SEM was used to observe the surface of paper and found that the microstructure of paper gradually broke and sunken as time. The result of AFM showed that the fiber structure on the surface of paper was gradually fragmented in the aging process. The contents of potassium ion, sodium ion, phosphate ion and chloride ion in paper of different ages were determined by ion chromatography, and found thatthe content of sodium ion decreased gradually, while the contents of other ions increased in the ageing process. The experimental results showed that the micro-structure and composition of newspaper changed regularly with the prolongation of storage time, which could provide evidence for the identification of aging paper.
2021, 49(11): 1897-1907
doi: 10.19756/j.issn.0253-3820.210513
Abstract:
A novel and simple photoelectrochemical (PEC) sensor for ultrasensitive detection of mercury ion (Hg2+) was fabricated based on metal organic framework-derived porous titanium dioxide-cadmium selenide quantum dots (M-TiO2-CdSe QDs) composites. The morphology and structure of different materials were characterized by field emission scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The performance of the sensor was studied by current time method (i-t) and electrochemical impedance spectroscopy technology (EIS). The results showed that the prepared M-TiO2 not only retained the original morphology and structure of MIL-125(Ti), but also exhibited more abundant pore structure and good PEC properties. Comparing with M-TiO2, the as-prepared M-TiO2-CdSe QDs nanocomposite exhibited excellent PEC performances including about 2-fold enhancement of photocurrent intensity, which were ascribed to the large surface of M-TiO2 and the introduction of CdSe QDs. Based on the selective inhibitory effect of Hg2+ on the photocurrent intensity of the M-TiO2-CdSe QDs PEC system, a novel PEC sensor for Hg2+ concentration determination was constructed, with a wide linear response range of 0.005-5 nmol/L and a detection limit of 4.2 pmol/L (S/N=3). The detection method was used for analysis of Hg2+ in real water samples with the spiked recoveries of 96%-110%, and the possible detection mechanism of the M-TiO2-CdSe QDs PEC system was also discussed.
A novel and simple photoelectrochemical (PEC) sensor for ultrasensitive detection of mercury ion (Hg2+) was fabricated based on metal organic framework-derived porous titanium dioxide-cadmium selenide quantum dots (M-TiO2-CdSe QDs) composites. The morphology and structure of different materials were characterized by field emission scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and ultraviolet-visible diffuse reflectance spectroscopy (UV-Vis DRS). The performance of the sensor was studied by current time method (i-t) and electrochemical impedance spectroscopy technology (EIS). The results showed that the prepared M-TiO2 not only retained the original morphology and structure of MIL-125(Ti), but also exhibited more abundant pore structure and good PEC properties. Comparing with M-TiO2, the as-prepared M-TiO2-CdSe QDs nanocomposite exhibited excellent PEC performances including about 2-fold enhancement of photocurrent intensity, which were ascribed to the large surface of M-TiO2 and the introduction of CdSe QDs. Based on the selective inhibitory effect of Hg2+ on the photocurrent intensity of the M-TiO2-CdSe QDs PEC system, a novel PEC sensor for Hg2+ concentration determination was constructed, with a wide linear response range of 0.005-5 nmol/L and a detection limit of 4.2 pmol/L (S/N=3). The detection method was used for analysis of Hg2+ in real water samples with the spiked recoveries of 96%-110%, and the possible detection mechanism of the M-TiO2-CdSe QDs PEC system was also discussed.
2021, 49(11): 1908-1918
doi: 10.19756/j.issn.0253-3820.210549
Abstract:
Novel flower-like estradiol lightweight magnetic surface molecularly imprinted polymers (FL-MMIPs) were prepared for the selective adsorption of estradiol (E2) using aniline (AN) as functional monomer, ammonium persulfate (APS) as initiator, E2 as template molecule, E44 epoxy as protective layer, and etched magnetic nanomaterials (E-Fe3O4) as carriers by surface molecularly imprinting, fixed template, and etching techniques. The prepared molecularly imprinted polymers were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The results showed that the imprinted layer of AN was successfully coated on the surface of FL-MMIPs, and the materials had uniform particle size, stable crystal structure, and good superparamagnetism. The adsorption properties of the materials were investigated by kinetic adsorption, isothermal adsorption, selective adsorption, reusability and reproducibility experiments. In addition, the adsorption capacity and imprinting factor of the nanomaterials were 30.46 mg/g and 2.44, respectively. The nanomaterials showed fast mass transfer rate (20 min) and good reusability (the adsorption efficiency was 96.8% after 8 cycles). This study provided a new method for determination of E2 in environmental water.
Novel flower-like estradiol lightweight magnetic surface molecularly imprinted polymers (FL-MMIPs) were prepared for the selective adsorption of estradiol (E2) using aniline (AN) as functional monomer, ammonium persulfate (APS) as initiator, E2 as template molecule, E44 epoxy as protective layer, and etched magnetic nanomaterials (E-Fe3O4) as carriers by surface molecularly imprinting, fixed template, and etching techniques. The prepared molecularly imprinted polymers were characterized by transmission electron microscopy (TEM), scanning electron microscope (SEM), Fourier transform infrared (FT-IR) spectroscopy, X-ray diffraction (XRD), and vibrating sample magnetometer (VSM). The results showed that the imprinted layer of AN was successfully coated on the surface of FL-MMIPs, and the materials had uniform particle size, stable crystal structure, and good superparamagnetism. The adsorption properties of the materials were investigated by kinetic adsorption, isothermal adsorption, selective adsorption, reusability and reproducibility experiments. In addition, the adsorption capacity and imprinting factor of the nanomaterials were 30.46 mg/g and 2.44, respectively. The nanomaterials showed fast mass transfer rate (20 min) and good reusability (the adsorption efficiency was 96.8% after 8 cycles). This study provided a new method for determination of E2 in environmental water.
2021, 49(11): 1919-1925
doi: 10.19756/j.issn.0253-3820.201754
Abstract:
Ascorbic acid, uric acid and xanthine in human urine are important markers of many diseases. A method for simultaneous detection of ascorbic acid, uric acid and xanthine in human urine by high performance liquid chromatography based on column tandem technique was established. The separation of these three compounds was the key to simultaneously analyze the three compounds to a certain extent because the conventional liquid chromatography could not effectively separate these highly polar substances simultaneously. The Innoval ASB C18 was coupled with the hydrophilic interaction chromatography (HILIC) column to trigger off a dual-column series separation mode. The separation performance of the two columns was complementary to achieve baseline separation of the three target analytes. The results showed that a single HILIC column could not achieve the baseline separation of the three analytes. The C18 column also showed very weak retention to the three analytes. The retention time was so early that the target analyte peaks might be interfered by the solvent peaks. Only the tandem of these two columns could achieve the baseline separation for the three analytes. Ultimately, an analytical method for simultaneous analysis of ascorbic acid, uric acid and xanthine in human urine with the C18 column tandem HILIC column was established. The correlation coefficient was good in the linear range of 0.005-20 mg/L, and limits of detection (LODs) of ascorbic acid, uric acid, and xanthine were 1.06 μg/L, 0.94 μg/L and 0.46 μg/L, respectively. The three target analytes could be found in actual human urine by the proposed method. The contents of ascorbic acid, uric acid and xanthine were 0.47-4.70, 6.91-8.01 and 0.10-0.19 mg/L, respectively. The recoveries of the spiked urine samples were 86.2%-117.9%, and the relative standard deviation (RSD) was less than 9.3%. The established high performance liquid chromatography based on column tandem analytical method was simple, fast and efficient, and could be used for separation and simultaneous determination of ascorbic acid, uric acid and xanthine in human urine.
Ascorbic acid, uric acid and xanthine in human urine are important markers of many diseases. A method for simultaneous detection of ascorbic acid, uric acid and xanthine in human urine by high performance liquid chromatography based on column tandem technique was established. The separation of these three compounds was the key to simultaneously analyze the three compounds to a certain extent because the conventional liquid chromatography could not effectively separate these highly polar substances simultaneously. The Innoval ASB C18 was coupled with the hydrophilic interaction chromatography (HILIC) column to trigger off a dual-column series separation mode. The separation performance of the two columns was complementary to achieve baseline separation of the three target analytes. The results showed that a single HILIC column could not achieve the baseline separation of the three analytes. The C18 column also showed very weak retention to the three analytes. The retention time was so early that the target analyte peaks might be interfered by the solvent peaks. Only the tandem of these two columns could achieve the baseline separation for the three analytes. Ultimately, an analytical method for simultaneous analysis of ascorbic acid, uric acid and xanthine in human urine with the C18 column tandem HILIC column was established. The correlation coefficient was good in the linear range of 0.005-20 mg/L, and limits of detection (LODs) of ascorbic acid, uric acid, and xanthine were 1.06 μg/L, 0.94 μg/L and 0.46 μg/L, respectively. The three target analytes could be found in actual human urine by the proposed method. The contents of ascorbic acid, uric acid and xanthine were 0.47-4.70, 6.91-8.01 and 0.10-0.19 mg/L, respectively. The recoveries of the spiked urine samples were 86.2%-117.9%, and the relative standard deviation (RSD) was less than 9.3%. The established high performance liquid chromatography based on column tandem analytical method was simple, fast and efficient, and could be used for separation and simultaneous determination of ascorbic acid, uric acid and xanthine in human urine.
2021, 49(11): 1926-1936
doi: 10.19756/j.issn.0253-3820.210525
Abstract:
Fluorescent whitening agents (FWAs) are a class of fluorescent dyes with whitening effects, and are widely used in textiles, paper, detergents, cosmetics, plastic toys, food contact materials and other products. In view of their harm to people and the environment, FWAs are limited by relevant regulations at home and abroad. In this work, based on high performance liquid chromatography-high resolution mass spectrometry technique, a method was established for non-targeted screening and identification of 31 kinds of FWAs, which belonged to 7 different classes, in children's masks. And the method was successfully applied to the analysis of real masks samples from 18 different brands. Using methanol:water (3:1, V/V) solution as extraction solvent, the FWAs in children's masks were extracted by ultrasonic assisted extraction. For chromatographic separation, 5 mmol/L ammonium acetate and methanol were used as the mobile phase and the gradient elution was optimized. A Full mass scan and data-dependent MS/MS mode (Full MS/dd-MS2) was used for high-resolution mass spectrometry detection. Qualitative confirmation of compounds was based on multi-dimensional information, such as exact mass, parent ion isotope abundance ratio, predicted retention time and predicted fragment ion. The fragment structures of 4 kinds of FWAs detected in children's masks were firstly deduced by Xcalibur, Mass Frontier and ACD/MS Fragmenter software, and then compared with literature reports. Finally, the accurate qualitative and quantitative analyses were carried out by the reference standard materials of FWAs, and the methodological verification of the non-targeting method was carried out by using representative compounds. The established non-target screening method could achieve rapid analysis of FWAs with high throughput, without purchasing all reference standards and complicated method development. The method could satisfy both the regulations requirements and identification of non-target compounds. Especially during the epidemic period, it could provide an effective technical support for the quality control of masks and the protection of children's health.
Fluorescent whitening agents (FWAs) are a class of fluorescent dyes with whitening effects, and are widely used in textiles, paper, detergents, cosmetics, plastic toys, food contact materials and other products. In view of their harm to people and the environment, FWAs are limited by relevant regulations at home and abroad. In this work, based on high performance liquid chromatography-high resolution mass spectrometry technique, a method was established for non-targeted screening and identification of 31 kinds of FWAs, which belonged to 7 different classes, in children's masks. And the method was successfully applied to the analysis of real masks samples from 18 different brands. Using methanol:water (3:1, V/V) solution as extraction solvent, the FWAs in children's masks were extracted by ultrasonic assisted extraction. For chromatographic separation, 5 mmol/L ammonium acetate and methanol were used as the mobile phase and the gradient elution was optimized. A Full mass scan and data-dependent MS/MS mode (Full MS/dd-MS2) was used for high-resolution mass spectrometry detection. Qualitative confirmation of compounds was based on multi-dimensional information, such as exact mass, parent ion isotope abundance ratio, predicted retention time and predicted fragment ion. The fragment structures of 4 kinds of FWAs detected in children's masks were firstly deduced by Xcalibur, Mass Frontier and ACD/MS Fragmenter software, and then compared with literature reports. Finally, the accurate qualitative and quantitative analyses were carried out by the reference standard materials of FWAs, and the methodological verification of the non-targeting method was carried out by using representative compounds. The established non-target screening method could achieve rapid analysis of FWAs with high throughput, without purchasing all reference standards and complicated method development. The method could satisfy both the regulations requirements and identification of non-target compounds. Especially during the epidemic period, it could provide an effective technical support for the quality control of masks and the protection of children's health.
2021, 49(11): 1937-1944
doi: 10.19756/j.issn.0253-3820.210526
Abstract:
Two different types of 3D printers were employed for exploring the electroosmotic performance of microfluidic electrophoresis chip:one was Stereo lithography appearance (SLA) type using resin as material for design and preparation of four different kinds of micro-channels, i.e. regular triangle, square, 3/4 regular icosagon and 3/4 circle; the other was Fused deposition modeling (FDM) type using polymer filament as material for design and preparation of square channel. The influence of pH value of buffer solution, microchannel cross-section shape and types of 3D printers & craftsmanship of fabrication were investigated by current monitoring method. The results showed that the electroosmotic mobility of microchannel was negatively correlated with the pH value of buffer solution in the SLA 3D printed electrophoresis chip, whose surface carried positive charge. Among the four different microchannels, the square one had the largest μEOF value. As for the FDM 3D printed electrophoresis chip, it had opposite linear relation between EOF mobility and pH value, demonstrating its surface carried negative charge, but with better linearity and lower electroosmotic mobility. SLA type had multiple production potential but high viscosity resin, which was difficult to remove from microchannels, made the process complex and resulted in the final chip lack of fabrication stability. FDM type was advantageous in fabrication stability, but the diversity of microchannels' shape was limited. This study developed a new method for the fabrication of microchannels and explored the electroosmotic performance of them, which was expected to provide scientific theories for 3D printed microfluidic electrophoresis chip as well as its application in electrophoretic ananlysis.
Two different types of 3D printers were employed for exploring the electroosmotic performance of microfluidic electrophoresis chip:one was Stereo lithography appearance (SLA) type using resin as material for design and preparation of four different kinds of micro-channels, i.e. regular triangle, square, 3/4 regular icosagon and 3/4 circle; the other was Fused deposition modeling (FDM) type using polymer filament as material for design and preparation of square channel. The influence of pH value of buffer solution, microchannel cross-section shape and types of 3D printers & craftsmanship of fabrication were investigated by current monitoring method. The results showed that the electroosmotic mobility of microchannel was negatively correlated with the pH value of buffer solution in the SLA 3D printed electrophoresis chip, whose surface carried positive charge. Among the four different microchannels, the square one had the largest μEOF value. As for the FDM 3D printed electrophoresis chip, it had opposite linear relation between EOF mobility and pH value, demonstrating its surface carried negative charge, but with better linearity and lower electroosmotic mobility. SLA type had multiple production potential but high viscosity resin, which was difficult to remove from microchannels, made the process complex and resulted in the final chip lack of fabrication stability. FDM type was advantageous in fabrication stability, but the diversity of microchannels' shape was limited. This study developed a new method for the fabrication of microchannels and explored the electroosmotic performance of them, which was expected to provide scientific theories for 3D printed microfluidic electrophoresis chip as well as its application in electrophoretic ananlysis.
