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2016 Volume 44 Issue 10
2016, 44(10): 1471-1476
doi: 10.11895/j.issn.0253-3820.160418
Abstract:
By taking advantage of atomic force microscopes'(AFM) capability of manipulating and processing materials on the microscale, we discovered and investigated a top-down preparation method of biological macromolecular nano-fibril arrays. 50 μg/mL solution of rat tail type I collagen monomers was used to coat the mica surface to form a protein membrane. In the AFM Contact Mode, the AFM tip then manipulated the membrane with appropriate force between 100 nN and 1 mN, thus producing patterned collagen nano-fibril arrays with specific orientations. The nano-fibrils are averagely 2-5 nm in height and 150-350 nm in width. Based on the relationship between the structure of such nano-fibril arrays and the AFM scanning patterns, we investigated and discussed the formation of the protein fibril arrays, and verified the molecular broom mechanism of the AFM tip. This preparation method could potentially provide an efficient technique to manufacture cell culture vessels, produce biological probes with high specificities, and synthesize novel micro/nano materials as well.
By taking advantage of atomic force microscopes'(AFM) capability of manipulating and processing materials on the microscale, we discovered and investigated a top-down preparation method of biological macromolecular nano-fibril arrays. 50 μg/mL solution of rat tail type I collagen monomers was used to coat the mica surface to form a protein membrane. In the AFM Contact Mode, the AFM tip then manipulated the membrane with appropriate force between 100 nN and 1 mN, thus producing patterned collagen nano-fibril arrays with specific orientations. The nano-fibrils are averagely 2-5 nm in height and 150-350 nm in width. Based on the relationship between the structure of such nano-fibril arrays and the AFM scanning patterns, we investigated and discussed the formation of the protein fibril arrays, and verified the molecular broom mechanism of the AFM tip. This preparation method could potentially provide an efficient technique to manufacture cell culture vessels, produce biological probes with high specificities, and synthesize novel micro/nano materials as well.
2016, 44(10): 1477-1481
doi: 10.11895/j.issn.0253-3820.160204
Abstract:
A novel test strip for rapid detection of cimaterol was prepared by combining highly specific selectivity of molecularly imprinted technology with convenience and rapid response performance of test strip. The cimaterol molecularly imprinted polymers (MIPs) were prepared through chemical polymerization method, and the nitrocellulose membrane was immersed into MIPs solution. After that, the template molecules were eluted and then a clipping step was conducted for obtaining the test strip. After re-adsorption of cimaterol, fluorescent dye Eosin Y was added onto the surface reaction zone on the strip. Qualitative and quantitative analysis could be realized via determining fluorescence quenching in the reaction zone. The experimental results showed that the quenching of fluorescence had a good linear relationship with the cimaterol concentration ranging from 0.01 to 100 μg/mL with a limit of detection of 0.01 μg/mL. The molecular imprinting test strips provided a convenient way in practical application especially for the quick detection of pork and fodder sample on site.
A novel test strip for rapid detection of cimaterol was prepared by combining highly specific selectivity of molecularly imprinted technology with convenience and rapid response performance of test strip. The cimaterol molecularly imprinted polymers (MIPs) were prepared through chemical polymerization method, and the nitrocellulose membrane was immersed into MIPs solution. After that, the template molecules were eluted and then a clipping step was conducted for obtaining the test strip. After re-adsorption of cimaterol, fluorescent dye Eosin Y was added onto the surface reaction zone on the strip. Qualitative and quantitative analysis could be realized via determining fluorescence quenching in the reaction zone. The experimental results showed that the quenching of fluorescence had a good linear relationship with the cimaterol concentration ranging from 0.01 to 100 μg/mL with a limit of detection of 0.01 μg/mL. The molecular imprinting test strips provided a convenient way in practical application especially for the quick detection of pork and fodder sample on site.
2016, 44(10): 1482-1486
doi: 10.11895/j.issn.0253-3820.160409
Abstract:
The fluorescence of Rhodamine B could be quenched by the manner of photo-induced electron transfer with Cu2-xSe nanoparticles as the energy receptor and Rhodamine B as the energy donor. However, L-cysteine was capable of recovering the fluorescence of Rhodamine B, and the fluorescence intensity was proportional to the concentrations of L-cysteine. Based on that, a novel method for detecting L-cysteine was established. After mixing L-cysteine and Rhodamine B pretreated by Cu2-xSe nanoparticles at pH 4.6 and 30℃ for 2 min, a linear relationship was obtained between the fluorescence intensity of Rhodamine B at 575 nm and the concentrations of L-cysteine in the range of 2.5×10-7-1.1×10-6 mol/L. This method was used in the determination of L-cysteine with a detection limit (3σ/k) of 5.5×10-8 mol/L. The common amino acids presented little interference for the L-cysteine detection.
The fluorescence of Rhodamine B could be quenched by the manner of photo-induced electron transfer with Cu2-xSe nanoparticles as the energy receptor and Rhodamine B as the energy donor. However, L-cysteine was capable of recovering the fluorescence of Rhodamine B, and the fluorescence intensity was proportional to the concentrations of L-cysteine. Based on that, a novel method for detecting L-cysteine was established. After mixing L-cysteine and Rhodamine B pretreated by Cu2-xSe nanoparticles at pH 4.6 and 30℃ for 2 min, a linear relationship was obtained between the fluorescence intensity of Rhodamine B at 575 nm and the concentrations of L-cysteine in the range of 2.5×10-7-1.1×10-6 mol/L. This method was used in the determination of L-cysteine with a detection limit (3σ/k) of 5.5×10-8 mol/L. The common amino acids presented little interference for the L-cysteine detection.
2016, 44(10): 1487-1494
doi: 10.11895/j.issn.0253-3820.160508
Abstract:
Based on intermolecular split G-quardruplex-hemin DNAzymes, a biosensor for detection of silver ions and cysteine was developed with magnetic nanoparticles (MNPs) as carrier to immobilize the DNA probes. Since Ag+ chelates guanine bases at the binding sites which are involved in G-quadruplex formation, the presence of Ag+ may inhibit G-quartets connected by Hoogsteen-type base pairing and disrupt G-quadruplexes structures, which decreases the peroxidase activity of G-quadruplex-hemin DNAzymes that efficiently catalyze H2O2-mediated reactions, such as the oxidation of ABTS (2,2'-azinobis(3-ethylbenzothiozoline)-6-sulfonic acid) by H2O2. Moreover, in the presence of L-cysteine, it was used as a competitor by the strongly Ag-S to release Ag+ from G-rich oligonucleotides, promoting the reformation of G-quadruplexes and increasing the peroxidase activity, which catalyzes the ABTS-H2O2 reaction system. In this experiment, the efficient separation from real sample was achieved using magnetic nanoparticles as a solid phase carrier to effectively increase the detection sensitivity and decrease the background signal. Under the optimum conditions, a high linear relationship between the UV absorbance and the Ag+ concentration was established in the range of 0.5-100 nmol/L with a detection limit of 0.2 nmol/L. The calibration curve of cysteine was identified in the range from 0.1 to 80 nmol/L and the detection limit was as low as 0.04 nmol/L.
Based on intermolecular split G-quardruplex-hemin DNAzymes, a biosensor for detection of silver ions and cysteine was developed with magnetic nanoparticles (MNPs) as carrier to immobilize the DNA probes. Since Ag+ chelates guanine bases at the binding sites which are involved in G-quadruplex formation, the presence of Ag+ may inhibit G-quartets connected by Hoogsteen-type base pairing and disrupt G-quadruplexes structures, which decreases the peroxidase activity of G-quadruplex-hemin DNAzymes that efficiently catalyze H2O2-mediated reactions, such as the oxidation of ABTS (2,2'-azinobis(3-ethylbenzothiozoline)-6-sulfonic acid) by H2O2. Moreover, in the presence of L-cysteine, it was used as a competitor by the strongly Ag-S to release Ag+ from G-rich oligonucleotides, promoting the reformation of G-quadruplexes and increasing the peroxidase activity, which catalyzes the ABTS-H2O2 reaction system. In this experiment, the efficient separation from real sample was achieved using magnetic nanoparticles as a solid phase carrier to effectively increase the detection sensitivity and decrease the background signal. Under the optimum conditions, a high linear relationship between the UV absorbance and the Ag+ concentration was established in the range of 0.5-100 nmol/L with a detection limit of 0.2 nmol/L. The calibration curve of cysteine was identified in the range from 0.1 to 80 nmol/L and the detection limit was as low as 0.04 nmol/L.
2016, 44(10): 1495-1503
doi: 10.11895/j.issn.0253-3820.160394
Abstract:
A spirobenzopyran-based probe (L) for the detection of Cu2+ and hydrazine was synthesized by using 4-methyl-2,6-diformylphenol and 1,3,3-trimethyl-2-methyleneindoline, and its structure was characterized by 1H NMR, 13C NMR, FT-IR and H RMS(ESI-MS). The recognition properties of the probe L with nineteen kinds of metral ions, eighteen kinds of anion ions and nine kinds of amine compounds had been investigated in Tris-HCl(pH=7.40)-ethanol solution (1:1, V/V) by UV-Vis, fluorescence spectrophotometry, 1H NMR titration and MS. The results showed that the probe L exhibited higher selectivity and sensitivity towards Cu2+ and hydrazine over other interfering objects in Tris-HCl(pH=7.40)-ethanol solution(1:1, V/V), and the color changes of L caused by Cu2+ and hydrazine could be observed by naked eyes. Thus, L could be loaded as test paper for detecting Cu2+ at μmol/L level in water solution by naked eyes. Notably, probe L could be used to detect hydrazine in liquid and gas state with different concentrations by detecting the color changes from readily prepared TLC plates. On the basis of this, the probe L was used in the determination of Cu2+ in the water and drug samples with recoveries of 83.5%-111.0% and RSD of 4.0%. The results showed that this probe L had potential applications in the monitoring of environmental pollution and the analysis of Cu2+ and hydrazine in drug.
A spirobenzopyran-based probe (L) for the detection of Cu2+ and hydrazine was synthesized by using 4-methyl-2,6-diformylphenol and 1,3,3-trimethyl-2-methyleneindoline, and its structure was characterized by 1H NMR, 13C NMR, FT-IR and H RMS(ESI-MS). The recognition properties of the probe L with nineteen kinds of metral ions, eighteen kinds of anion ions and nine kinds of amine compounds had been investigated in Tris-HCl(pH=7.40)-ethanol solution (1:1, V/V) by UV-Vis, fluorescence spectrophotometry, 1H NMR titration and MS. The results showed that the probe L exhibited higher selectivity and sensitivity towards Cu2+ and hydrazine over other interfering objects in Tris-HCl(pH=7.40)-ethanol solution(1:1, V/V), and the color changes of L caused by Cu2+ and hydrazine could be observed by naked eyes. Thus, L could be loaded as test paper for detecting Cu2+ at μmol/L level in water solution by naked eyes. Notably, probe L could be used to detect hydrazine in liquid and gas state with different concentrations by detecting the color changes from readily prepared TLC plates. On the basis of this, the probe L was used in the determination of Cu2+ in the water and drug samples with recoveries of 83.5%-111.0% and RSD of 4.0%. The results showed that this probe L had potential applications in the monitoring of environmental pollution and the analysis of Cu2+ and hydrazine in drug.
2016, 44(10): 1504-1513
doi: 10.11895/j.issn.0253-3820.160333
Abstract:
A method was developed for the rapid screening and confirmation of 18 perfluorinated compounds (PFCs) and 21 precursors in fish muscle by solid phase extraction and liquid chromatography coupled with quadrupole/exactive orbitrap mass spectrometry (LC-Q Exactive Orbitrap MS). In this method, the sample was firstly extracted with acetonitrile-water (90:10, V/V), cleaned-up by solid-phase extraction using Oasis PRiME HLB column. Then, 39 target compounds were separated on a BEH C18 (2.1 mm×100 mm, 1.7 μm) column, and the background interference caused by LC system was eliminated by a short C18 HPLC column located between the mixer and the auto sampler. In the process of quantification and qualification, a full MS/dd-MS2 experiment was adopted in mass spectrometry acquisition, accompanied with the full scan MS date for quantification, as well as the date dependent MS2 product ion spectra for qualification. The mass accuracy error was less than 3×10-6, and the calibration curves were linear well with correlation coefficient over 0.99. The limits of detection ranged from 0.02 to 0.50 μg/kg. The average spiked recoveries for 39 target compounds were between 61.7% and 122.0%, with relative standard derivations (RSDs) from 6.9% to 18.8%. The developed method was successfully applied to the simultaneous determination of 18 PFCs and 21 precursors in fish muscle with satisfactory results.
A method was developed for the rapid screening and confirmation of 18 perfluorinated compounds (PFCs) and 21 precursors in fish muscle by solid phase extraction and liquid chromatography coupled with quadrupole/exactive orbitrap mass spectrometry (LC-Q Exactive Orbitrap MS). In this method, the sample was firstly extracted with acetonitrile-water (90:10, V/V), cleaned-up by solid-phase extraction using Oasis PRiME HLB column. Then, 39 target compounds were separated on a BEH C18 (2.1 mm×100 mm, 1.7 μm) column, and the background interference caused by LC system was eliminated by a short C18 HPLC column located between the mixer and the auto sampler. In the process of quantification and qualification, a full MS/dd-MS2 experiment was adopted in mass spectrometry acquisition, accompanied with the full scan MS date for quantification, as well as the date dependent MS2 product ion spectra for qualification. The mass accuracy error was less than 3×10-6, and the calibration curves were linear well with correlation coefficient over 0.99. The limits of detection ranged from 0.02 to 0.50 μg/kg. The average spiked recoveries for 39 target compounds were between 61.7% and 122.0%, with relative standard derivations (RSDs) from 6.9% to 18.8%. The developed method was successfully applied to the simultaneous determination of 18 PFCs and 21 precursors in fish muscle with satisfactory results.
2016, 44(10): 1514-1520
doi: 10.11895/j.issn.0253-3820.160328
Abstract:
A high performance liquid chromatographic (HPLC) method was extablished for determination of the content of 7 polycyclic aromatic hydrocarbons (PAHs) in soil and earthworm samples based on accelerated solvent extraction (ASE) for extraction and solid phase extraction (SPE) column for sample purification. In this method, the samples were first extracted by the mixed solution of n-hexane and acetone extraction (4:1, V/V), and then purified by SPE column (silica gel column for soil sample purification and Al2O3-silica gel column for earthworm sample purification), eluted by 10 mL of elution of n-hexane and dichloromethane (9:1, V/V), and evaporated to dryness with rotary evaporator. After that, the pretreated samples were re-dissolved with acetonitrile to a constant volume, followed by a filtration with a 0.22-μm organic filter membrane for the quantification by HPLC. The recoveries of the method for 7 PAHs were 83.5%-110.2% in soil samples and 81.2%-97.1% in earthworm samples. The detection limits of the method for 7 PAHs were 0.15-0.85 μg/kg. The method had good reproducibility and met the quality control requirements of sample analysis.
A high performance liquid chromatographic (HPLC) method was extablished for determination of the content of 7 polycyclic aromatic hydrocarbons (PAHs) in soil and earthworm samples based on accelerated solvent extraction (ASE) for extraction and solid phase extraction (SPE) column for sample purification. In this method, the samples were first extracted by the mixed solution of n-hexane and acetone extraction (4:1, V/V), and then purified by SPE column (silica gel column for soil sample purification and Al2O3-silica gel column for earthworm sample purification), eluted by 10 mL of elution of n-hexane and dichloromethane (9:1, V/V), and evaporated to dryness with rotary evaporator. After that, the pretreated samples were re-dissolved with acetonitrile to a constant volume, followed by a filtration with a 0.22-μm organic filter membrane for the quantification by HPLC. The recoveries of the method for 7 PAHs were 83.5%-110.2% in soil samples and 81.2%-97.1% in earthworm samples. The detection limits of the method for 7 PAHs were 0.15-0.85 μg/kg. The method had good reproducibility and met the quality control requirements of sample analysis.
2016, 44(10): 1521-1527
doi: 10.11895/j.issn.0253-3820.160361
Abstract:
S-Palmitoylation in protein is one of the most important kinds of lipid modification and plays a vital role in cell signal transduction, metabolism and other processes, which is formed by covalent binding of palmitic acid with the sulfhydryl group of cysteine residue in protein through thioester bond. In the present study, acyl-biotin exchange reaction was performed to convert S-palmitic acid on the hemagglutinin protein from influenza A virus into biotin-labeled tag. The biotin-labeled protein was then enriched by streptavidin beads and further purified by electrophoresis, followed by in-gel digestion. The results showed that the ratio of biotin concentration of the sample with hydroxylamine treatment (+HA) to that of the sample without hydroxylamine treatment (-HA) was larger than 3. Mass spectrometric analysis of the digestion mixture of the enriched hemagglutinin protein from influenza A virus identified two s-palmitoylation modification sites that were located on carboxyl terminal region of hemagglutinin protein such as Cys562 and Cys565, respectively. This research offers a specific and effective method for large-scale analysis of S-palmitoylated proteins.
S-Palmitoylation in protein is one of the most important kinds of lipid modification and plays a vital role in cell signal transduction, metabolism and other processes, which is formed by covalent binding of palmitic acid with the sulfhydryl group of cysteine residue in protein through thioester bond. In the present study, acyl-biotin exchange reaction was performed to convert S-palmitic acid on the hemagglutinin protein from influenza A virus into biotin-labeled tag. The biotin-labeled protein was then enriched by streptavidin beads and further purified by electrophoresis, followed by in-gel digestion. The results showed that the ratio of biotin concentration of the sample with hydroxylamine treatment (+HA) to that of the sample without hydroxylamine treatment (-HA) was larger than 3. Mass spectrometric analysis of the digestion mixture of the enriched hemagglutinin protein from influenza A virus identified two s-palmitoylation modification sites that were located on carboxyl terminal region of hemagglutinin protein such as Cys562 and Cys565, respectively. This research offers a specific and effective method for large-scale analysis of S-palmitoylated proteins.
2016, 44(10): 1528-1532
doi: 10.11895/j.issn.0253-3820.160321
Abstract:
A simple and sensitive headspace gas chromatographic method was developed and validated for simultaneous determination of methanol, ethanol, dichloromethane, ethyl acetate, 1,4-dioxane and pyridine in topiroxostat. Under the conditions of optimization of stationary phase, heating temperature and equilibration time, the separation was achieved on a Rtx-200 column (30 m×0.25 mm×1 μm) filled with polytrifluoropropyl(methyl) siloxane by a flame ionization detector. The developed gas chromatographic method offered symmetric peak shape, and good resolution for all the 6 solvents. The good linearity was obtained for all the analytes with the correlation coefficients (R2) greater than 0.998. The limits of quantification were 0.006% for methanol, 0.005% for ethanol, 0.012% for dichloromethane, 0.0025% for ethyl acetate, 0.0076% for 1,4-dioxane and 0.004% for pyridine, respectively. The recoveries for 6 residual solvents at three spiked levels were in the range of 92.3%-100.3% with relative standard deviations of 0.32%-3.6%. The real sample analyses showed that this method was simple, fast and feasible for the simultaneous determination of 6 residual solvents in topiroxostat.
A simple and sensitive headspace gas chromatographic method was developed and validated for simultaneous determination of methanol, ethanol, dichloromethane, ethyl acetate, 1,4-dioxane and pyridine in topiroxostat. Under the conditions of optimization of stationary phase, heating temperature and equilibration time, the separation was achieved on a Rtx-200 column (30 m×0.25 mm×1 μm) filled with polytrifluoropropyl(methyl) siloxane by a flame ionization detector. The developed gas chromatographic method offered symmetric peak shape, and good resolution for all the 6 solvents. The good linearity was obtained for all the analytes with the correlation coefficients (R2) greater than 0.998. The limits of quantification were 0.006% for methanol, 0.005% for ethanol, 0.012% for dichloromethane, 0.0025% for ethyl acetate, 0.0076% for 1,4-dioxane and 0.004% for pyridine, respectively. The recoveries for 6 residual solvents at three spiked levels were in the range of 92.3%-100.3% with relative standard deviations of 0.32%-3.6%. The real sample analyses showed that this method was simple, fast and feasible for the simultaneous determination of 6 residual solvents in topiroxostat.
2016, 44(10): 1533-1538
doi: 10.11895/j.issn.0253-3820.160056
Abstract:
Combining with fluorescence excitation-emission matrix (EEM) spectra and parallel factor analysis, size exclusion chromatography (SEC) equipped with multi-excitation/emission scan model fluorescence detector was used for the analysis of the composition of dissolved organic matter (DOM) isolated from landfill leachates with different ages. The analytical results showed that the two leachate-derived DOMs both comprised protein- and humic-like substances. However, there were four kinds of protein-like matter in young landfill leachates, i.e., protein with high molecular weight, protein-like matter bound to humic-like substances with high or low molecular weight, and peptide/amino acids. While there were only two kinds of protein-like matter in old landfill leachates, i.e., protein with high molecular weight and protein-like matter bound to humic-like substances with high molecule weight. Compared with SEC, EEM spectra coupled with parallel factor analysis could identify the protein-like matter bound with humic-like substances or those presented as non-humic-like substances, though it could not identify the protein-like matter presented as protein and that presented as peptide/amino acids. The experimental results demonstrated that EEM spectra coupled with PARAFAC analysis and SEC could be used to characterize protein- and humic-like matter presented as different species.
Combining with fluorescence excitation-emission matrix (EEM) spectra and parallel factor analysis, size exclusion chromatography (SEC) equipped with multi-excitation/emission scan model fluorescence detector was used for the analysis of the composition of dissolved organic matter (DOM) isolated from landfill leachates with different ages. The analytical results showed that the two leachate-derived DOMs both comprised protein- and humic-like substances. However, there were four kinds of protein-like matter in young landfill leachates, i.e., protein with high molecular weight, protein-like matter bound to humic-like substances with high or low molecular weight, and peptide/amino acids. While there were only two kinds of protein-like matter in old landfill leachates, i.e., protein with high molecular weight and protein-like matter bound to humic-like substances with high molecule weight. Compared with SEC, EEM spectra coupled with parallel factor analysis could identify the protein-like matter bound with humic-like substances or those presented as non-humic-like substances, though it could not identify the protein-like matter presented as protein and that presented as peptide/amino acids. The experimental results demonstrated that EEM spectra coupled with PARAFAC analysis and SEC could be used to characterize protein- and humic-like matter presented as different species.
Study on Ecological and Chemical Characteristics of Rare Earth Elements in Tropical Marine Organisms
2016, 44(10): 1539-1546
doi: 10.11895/j.issn.0253-3820.160285
Abstract:
A total of 30 kinds of fish samples, 5 kinds of shellfish samples and 4 kinds of crustacean samples from the Nansha sea area of china were digested by microwave digestion system with HNO3-H2O2 as the digestion reagent. Then the contents (ICP-MS determination) and ecological chemical characteristics of rare earth elements (REE) were studied. The results showed that the method of microwave digestion-ICP-MS for the determination of rare earth elements was perfect, and the linear relationship for each element was good with r≥0.9997. The detection limit of the method could reach 1.0 ng/L with the relative standard deviation (RSD, n=3) of less than 5.0%. The recoveries of rare earth elements were between 91.50% and 106.67%. The total amount of rare earth in fish samples, shellfish samples and crustacean samples were 5.02-34.8 μg/kg, 30.4-1481 μg/kg and 103-863 μg/kg, respectively. The average enrichment contents of the rare earth in the 3 species was crustacean > shellfish > fish. The contents of 14 rare earth elements in fish/shellfish/crustaceans showed significantly positive correlation (r>0.80). The contents of light rare earth elements (La-Eu) were higher than that of heavy rare earth elements (Gd-Lu). The light and heavy rare earth elements had obvious fractionation, and the REE distribution pattern was consistent in fish/shellfish/crustacean with Gd negative anomaly. The δEu values had negative anomalies, similar to the δEu values in corresponding area sediment, and δCe values showed positive anomalies, which showed that Ce had different process of oxidation and reduction in the organism and sediment deposition. At the same time, the enrichment relationship of rare earth elements in sediment and organism was also studied. In this study, the content and distribution of rare earth elements in the tropical marine fish/shellfish/shellfish were analyzed, which could provide basic data for the study of the level and migration and accumulation of rare earth elements in the environment of the South China Sea.
A total of 30 kinds of fish samples, 5 kinds of shellfish samples and 4 kinds of crustacean samples from the Nansha sea area of china were digested by microwave digestion system with HNO3-H2O2 as the digestion reagent. Then the contents (ICP-MS determination) and ecological chemical characteristics of rare earth elements (REE) were studied. The results showed that the method of microwave digestion-ICP-MS for the determination of rare earth elements was perfect, and the linear relationship for each element was good with r≥0.9997. The detection limit of the method could reach 1.0 ng/L with the relative standard deviation (RSD, n=3) of less than 5.0%. The recoveries of rare earth elements were between 91.50% and 106.67%. The total amount of rare earth in fish samples, shellfish samples and crustacean samples were 5.02-34.8 μg/kg, 30.4-1481 μg/kg and 103-863 μg/kg, respectively. The average enrichment contents of the rare earth in the 3 species was crustacean > shellfish > fish. The contents of 14 rare earth elements in fish/shellfish/crustaceans showed significantly positive correlation (r>0.80). The contents of light rare earth elements (La-Eu) were higher than that of heavy rare earth elements (Gd-Lu). The light and heavy rare earth elements had obvious fractionation, and the REE distribution pattern was consistent in fish/shellfish/crustacean with Gd negative anomaly. The δEu values had negative anomalies, similar to the δEu values in corresponding area sediment, and δCe values showed positive anomalies, which showed that Ce had different process of oxidation and reduction in the organism and sediment deposition. At the same time, the enrichment relationship of rare earth elements in sediment and organism was also studied. In this study, the content and distribution of rare earth elements in the tropical marine fish/shellfish/shellfish were analyzed, which could provide basic data for the study of the level and migration and accumulation of rare earth elements in the environment of the South China Sea.
2016, 44(10): 1547-1554
doi: 10.11895/j.issn.0253-3820.160395
Abstract:
Environmental endocrine disruptors such as 17β-estradiol, are widely distributed with low concentration in the water, which has great harm to ecosystems and human health. To improve the detection sensitivity of 17β-estradiol, a Ru(bpy)32+/MWCNTs-Nafion-SiO2 modified electrode was firstly made by electrostatic adsorption of multi-walled carbon nanotubes (MWCNTs) and ion exchange of Nafion, binding nano-silica and immobilizing Ru(bpy)32+ on the surface of gold electrode. And then a molecular imprinting-electrochemiluminescence sensor (ECL-MIPs) was acquired by modifying the molecular imprinted membrane with sol-gel method for improving the specific selectivity. Under the optimum conditions (in 0.1 mol/L PBS, pH 7.4) at a scan rate of 100 mV/s and accumulation time of 20 min), there was a good linear relationship between the ECL intensity difference and 17β-estradiol concentration in the range of 0.03-2 μg/L, with a detection limit of 0.006 μg/L. The ECL-MIPs sensor was successfully applied to the determination of 17β-estradiol in the water samples with recoveries from 88.7% to 105.0%.
Environmental endocrine disruptors such as 17β-estradiol, are widely distributed with low concentration in the water, which has great harm to ecosystems and human health. To improve the detection sensitivity of 17β-estradiol, a Ru(bpy)32+/MWCNTs-Nafion-SiO2 modified electrode was firstly made by electrostatic adsorption of multi-walled carbon nanotubes (MWCNTs) and ion exchange of Nafion, binding nano-silica and immobilizing Ru(bpy)32+ on the surface of gold electrode. And then a molecular imprinting-electrochemiluminescence sensor (ECL-MIPs) was acquired by modifying the molecular imprinted membrane with sol-gel method for improving the specific selectivity. Under the optimum conditions (in 0.1 mol/L PBS, pH 7.4) at a scan rate of 100 mV/s and accumulation time of 20 min), there was a good linear relationship between the ECL intensity difference and 17β-estradiol concentration in the range of 0.03-2 μg/L, with a detection limit of 0.006 μg/L. The ECL-MIPs sensor was successfully applied to the determination of 17β-estradiol in the water samples with recoveries from 88.7% to 105.0%.
2016, 44(10): 1555-1561
doi: 10.11895/j.issn.0253-3820.160283
Abstract:
ZnO-SnO2 composite nanofibers of methane sensor were prepared by the double jets electrospinning method. A new chemical looping combustion type methane sensor was designed with ZnO-SnO2 composite nanofibers deposited onto Pt thermistor surface as catalytic thin film. The crystalline phase and microstructure of ZnO-SnO2 composite nanofibers were displayed using X-ray diffraction (XRD) and scanning electron microscope (SEM), and the chemical looping combustion reaction and electrochemical characteristic about methane and catalytic thin film were analyzed by CH4 temperature programmed reduction (CH4-TPR) and X-ray photoelectron spectroscopy (XPS). These characteristic tests of the methane sensor were carried out on the traits of sensitive performance, dynamic response, temperature, humidity, selective and stability by DL07-YJ108D type voltage measuring instrument. The conclusion demonstrated that methane sensor based on Zn50 composite nanofibers functioned as catalytic film. When the operating temperature was 350℃ and methane concentration was increased from 0.1 to 60 μg/L, the linearity and sensitivity of methane sensor were 99.4% and 0.12 V/(μg/L) respectively. Its high response was 8.2 V, and the dynamic response time and recover time of methane sensor were 5.4 and 10.8 s, respectively, with a high relatively humidity level of 95%. The response value of methane sensor was only decreased about 2.0% when it was continually applied in mine about 6 months.
ZnO-SnO2 composite nanofibers of methane sensor were prepared by the double jets electrospinning method. A new chemical looping combustion type methane sensor was designed with ZnO-SnO2 composite nanofibers deposited onto Pt thermistor surface as catalytic thin film. The crystalline phase and microstructure of ZnO-SnO2 composite nanofibers were displayed using X-ray diffraction (XRD) and scanning electron microscope (SEM), and the chemical looping combustion reaction and electrochemical characteristic about methane and catalytic thin film were analyzed by CH4 temperature programmed reduction (CH4-TPR) and X-ray photoelectron spectroscopy (XPS). These characteristic tests of the methane sensor were carried out on the traits of sensitive performance, dynamic response, temperature, humidity, selective and stability by DL07-YJ108D type voltage measuring instrument. The conclusion demonstrated that methane sensor based on Zn50 composite nanofibers functioned as catalytic film. When the operating temperature was 350℃ and methane concentration was increased from 0.1 to 60 μg/L, the linearity and sensitivity of methane sensor were 99.4% and 0.12 V/(μg/L) respectively. Its high response was 8.2 V, and the dynamic response time and recover time of methane sensor were 5.4 and 10.8 s, respectively, with a high relatively humidity level of 95%. The response value of methane sensor was only decreased about 2.0% when it was continually applied in mine about 6 months.
2016, 44(10): 1562-1567
doi: 10.11895/j.issn.0253-3820.160146
Abstract:
Using gatifloxacin (GTFX) as template molecule, magnetic surface molecularly imprinted polymers (M-MIPs) were prepared on the surface of modified magnetic silica (Fe3O4@SiO2) with surface molecular imprinting technique. The polymers were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The static adsorption experiments and Scatchard analysis suggested that there were two types of binding sites in the M-MIPs. The maximum adsorption capacities of M-MIPs and magnetic non-imprinted polymers (M-NIPs) for GTFX were 35.1 mg/g and 23.1 mg/g, respectively. The selectivity coefficients of GTFX M-MIPs to ciprofloxacin (CPFX), norfloxacin (NFLX), melamine (MEL) and tetracycline (TC) were 2.43, 5.18, 6.61 and 12.99, and the relative selectivity coefficients of M-MIPs to M-NIPs for these four drugs were 2.09, 1.95, 3.15 and 2.43, respectively, indicating the good specific recognition capability for GTFX. Combined with high performance liquid chromatographic analysis, the M-MIPs were applied to extract and enrich GTFX in milk sample with the recoveries more than 91.5%.
Using gatifloxacin (GTFX) as template molecule, magnetic surface molecularly imprinted polymers (M-MIPs) were prepared on the surface of modified magnetic silica (Fe3O4@SiO2) with surface molecular imprinting technique. The polymers were characterized by transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM). The static adsorption experiments and Scatchard analysis suggested that there were two types of binding sites in the M-MIPs. The maximum adsorption capacities of M-MIPs and magnetic non-imprinted polymers (M-NIPs) for GTFX were 35.1 mg/g and 23.1 mg/g, respectively. The selectivity coefficients of GTFX M-MIPs to ciprofloxacin (CPFX), norfloxacin (NFLX), melamine (MEL) and tetracycline (TC) were 2.43, 5.18, 6.61 and 12.99, and the relative selectivity coefficients of M-MIPs to M-NIPs for these four drugs were 2.09, 1.95, 3.15 and 2.43, respectively, indicating the good specific recognition capability for GTFX. Combined with high performance liquid chromatographic analysis, the M-MIPs were applied to extract and enrich GTFX in milk sample with the recoveries more than 91.5%.
2016, 44(10): 1568-1574
doi: 10.11895/j.issn.0253-3820.160254
Abstract:
To investigate the evolution law and influenced factors of dissolved organic matter for electron transfer capacity during initial landfill stage, dissolved organic matter (DOM) was extracted from landfill wastes at different depth. Shewanella oneidensis MR-1 and citrate iron (FeCit) were respectively used as electron donor and electron acceptor to measure electron donating capacity, electron accepting capacity and electron shuttling capacity. Afterwards, the influenced factors of electron transfer capacity were studied by analyzing spectral information. The results showed that protein-like components and humic-like components were able to transfer electrons, and they also accepted electrons from microorganisms. Electron donating capacity and electron accepting capacity increased firstly and then decreased. However, the electron shuttling capacity increased persistently during the landfill process. Protein-like components were the main components of dissolved organic matter during the initial landfill stage, and it was mainly responsible for the electron donoring capacity and electron accepting capacity of DOM. Electron shuttling capacity resulted from humic-like components during the cyclic redox process. Electron shuttling capacity persistently increased during the landfill process based on humic-like components generated during the stage.
To investigate the evolution law and influenced factors of dissolved organic matter for electron transfer capacity during initial landfill stage, dissolved organic matter (DOM) was extracted from landfill wastes at different depth. Shewanella oneidensis MR-1 and citrate iron (FeCit) were respectively used as electron donor and electron acceptor to measure electron donating capacity, electron accepting capacity and electron shuttling capacity. Afterwards, the influenced factors of electron transfer capacity were studied by analyzing spectral information. The results showed that protein-like components and humic-like components were able to transfer electrons, and they also accepted electrons from microorganisms. Electron donating capacity and electron accepting capacity increased firstly and then decreased. However, the electron shuttling capacity increased persistently during the landfill process. Protein-like components were the main components of dissolved organic matter during the initial landfill stage, and it was mainly responsible for the electron donoring capacity and electron accepting capacity of DOM. Electron shuttling capacity resulted from humic-like components during the cyclic redox process. Electron shuttling capacity persistently increased during the landfill process based on humic-like components generated during the stage.
2016, 44(10): 1575-1583
doi: 10.11895/j.issn.0253-3820.160172
Abstract:
A simple electrochemical sensor was constituted based on the glassy carbon electrode (GCE) surface modified with nafion-poly (diallyldimethylammonium chloride) functionalized graphene sheets (NA-PDDA-G) composite film and herring sperm double-stranded DNA for direct detection of DNA damage in vitro and evaluation of the antioxidant properties of ferulic acid (FA) and the aqueous extracts in Angelica Sinensis (EAS). Scanning electron microscopy (SEM) was used to characterize the morphologies of the fabricated sensor, while cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical performances of the modified electrode. Ru(NH3)63+ was used as an electroactive indicator to monitor DNA damage induced by hydroxyl radical (·OH) with square wave voltammetry (SWV). The fabricated sensor showed the greatest degree of DNA oxidation damage occurred under the conditions of 30-min incubation in Fenton reagent containing 1.0 mmol/L FeSO4 and 5.0 mmol/L H2O2 at pH 7.0. The antioxidant activity of extract in Angelica Sinensis (EAS) was stronger than that of FA, while they were all weaker than that of ascorbic acid (AA). The proposed sensor not only exhibited excellent stability and reproducibility, but would be a simple and novel method for assessment of antioxidant properties of medicinal herb components.
A simple electrochemical sensor was constituted based on the glassy carbon electrode (GCE) surface modified with nafion-poly (diallyldimethylammonium chloride) functionalized graphene sheets (NA-PDDA-G) composite film and herring sperm double-stranded DNA for direct detection of DNA damage in vitro and evaluation of the antioxidant properties of ferulic acid (FA) and the aqueous extracts in Angelica Sinensis (EAS). Scanning electron microscopy (SEM) was used to characterize the morphologies of the fabricated sensor, while cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the electrochemical performances of the modified electrode. Ru(NH3)63+ was used as an electroactive indicator to monitor DNA damage induced by hydroxyl radical (·OH) with square wave voltammetry (SWV). The fabricated sensor showed the greatest degree of DNA oxidation damage occurred under the conditions of 30-min incubation in Fenton reagent containing 1.0 mmol/L FeSO4 and 5.0 mmol/L H2O2 at pH 7.0. The antioxidant activity of extract in Angelica Sinensis (EAS) was stronger than that of FA, while they were all weaker than that of ascorbic acid (AA). The proposed sensor not only exhibited excellent stability and reproducibility, but would be a simple and novel method for assessment of antioxidant properties of medicinal herb components.
2016, 44(10): 1584-1592
doi: 10.11895/j.issn.0253-3820.160265
Abstract:
An effective method was developed for the simultaneous determination of 15 kinds of plants originated stimulants and exogenous medicines in herbal tea using solid phase extraction (SPE) combined with ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After centrifugation in high speed, the samples were purified using HLB SPE column at pH 4.0 (adjusted by formic acid). A total of 15 targets were separated on a BEH C18 column by gradient elution with acetonitrile-0.1% formic acid as mobile phase, ionized with positive and negative electrospray ionization (ESI+/-), detected under multiple reaction monitoring (MRM) mode, and quantified with external standard method. The method was validated by evaluating the linearity, recoveries, and precision. Favorable linearity was acquired in the concentration range of 1.0-200 μg/L, and the limits of detection (LODs) were ranged from 0.1 to 2.0 μg/L. At the spiked levels of 2.0-100 μg/L, the average recoveries presented 76.4%-107.0%, with the relative standard deviation (RSD, n=6) of 2.8% to 9.7% and intra-day precision of 2.7%-12.0%. The procedure was successfully applied to the determination of plants originated stimulants and external medicines in commercial herbal tea.
An effective method was developed for the simultaneous determination of 15 kinds of plants originated stimulants and exogenous medicines in herbal tea using solid phase extraction (SPE) combined with ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). After centrifugation in high speed, the samples were purified using HLB SPE column at pH 4.0 (adjusted by formic acid). A total of 15 targets were separated on a BEH C18 column by gradient elution with acetonitrile-0.1% formic acid as mobile phase, ionized with positive and negative electrospray ionization (ESI+/-), detected under multiple reaction monitoring (MRM) mode, and quantified with external standard method. The method was validated by evaluating the linearity, recoveries, and precision. Favorable linearity was acquired in the concentration range of 1.0-200 μg/L, and the limits of detection (LODs) were ranged from 0.1 to 2.0 μg/L. At the spiked levels of 2.0-100 μg/L, the average recoveries presented 76.4%-107.0%, with the relative standard deviation (RSD, n=6) of 2.8% to 9.7% and intra-day precision of 2.7%-12.0%. The procedure was successfully applied to the determination of plants originated stimulants and external medicines in commercial herbal tea.
2016, 44(10): 1593-1599
doi: 10.11895/j.issn.0253-3820.160239
Abstract:
Poly (dienedimethylammonium chloride) (PDDA) functionalized silver nanoparticles (AgNPs) prepared with PDDA as the protective and reductive agents was combined with graphene oxide (GO) to prepare PDDA functionalized cubic silver nanoparticles (C-AgNPs)/GO composite, which was then modified on a glassy carbon electrode (GCE) to form C-AgNPs-PDDA/GO/GCE. The surface morphologies of different modified electrodes were characterized by scanning electron microscope (SEM), and their corresponding cyclic voltammetric (CV) behaviors were investigated, indicating that the composite of C-AgNPs-PDDA/GO exhibited excellent electrocatalytic oxidation activity to DA and NO2-. By using differential pulse voltammetry, the responses of C-AgNPs-PDDA/GO/GCE were linear in the ranges of 0.030-0.300 μmol/L and 0.300-300 μmol/L with detection limit of 9.8 nmol/L (S/N=3) for DA, and 30.0-2300 μmol/L with detection limit of 12.6 μmol/L (S/N=3) for NO2-, respectively. The modified electrode displayed good selectivity, reproducibility and stability, and could be used for the simultaneous determination of DA and NO2- in human serum samples with recoveries of 97.4%-104.2% and 98.0%-102.8%, respectively. Compared with spectrophotometric method, the determination results were satisfactory, showing that the modified electrode possessed a potential application value.
Poly (dienedimethylammonium chloride) (PDDA) functionalized silver nanoparticles (AgNPs) prepared with PDDA as the protective and reductive agents was combined with graphene oxide (GO) to prepare PDDA functionalized cubic silver nanoparticles (C-AgNPs)/GO composite, which was then modified on a glassy carbon electrode (GCE) to form C-AgNPs-PDDA/GO/GCE. The surface morphologies of different modified electrodes were characterized by scanning electron microscope (SEM), and their corresponding cyclic voltammetric (CV) behaviors were investigated, indicating that the composite of C-AgNPs-PDDA/GO exhibited excellent electrocatalytic oxidation activity to DA and NO2-. By using differential pulse voltammetry, the responses of C-AgNPs-PDDA/GO/GCE were linear in the ranges of 0.030-0.300 μmol/L and 0.300-300 μmol/L with detection limit of 9.8 nmol/L (S/N=3) for DA, and 30.0-2300 μmol/L with detection limit of 12.6 μmol/L (S/N=3) for NO2-, respectively. The modified electrode displayed good selectivity, reproducibility and stability, and could be used for the simultaneous determination of DA and NO2- in human serum samples with recoveries of 97.4%-104.2% and 98.0%-102.8%, respectively. Compared with spectrophotometric method, the determination results were satisfactory, showing that the modified electrode possessed a potential application value.
2016, 44(10): 1600-1608
doi: 10.11895/j.issn.0253-3820.160152
Abstract:
Countercurrent chromatography is a kind of continuous and effective liquid-liquid partition chromatography with many unique characteristics such as large load capacity, no irreversible adsorption, high recovery rate, low risk of sample denaturation and so on, which has irreplaceable advantages in separation of protein and peptide. This review presents the advances of several kinds of new technology of countercurrent chromatography in the separation of protein and peptide. The developing prospect of this field is also discussed.
Countercurrent chromatography is a kind of continuous and effective liquid-liquid partition chromatography with many unique characteristics such as large load capacity, no irreversible adsorption, high recovery rate, low risk of sample denaturation and so on, which has irreplaceable advantages in separation of protein and peptide. This review presents the advances of several kinds of new technology of countercurrent chromatography in the separation of protein and peptide. The developing prospect of this field is also discussed.
2016, 44(10): 1609-1618
doi: 10.11895/j.issn.0253-3820.160137
Abstract:
The multimodal molecular imaging technology integrates the advantages of variant imaging methods which can provide a more comprehensive and accurate information in cancer diagnosis, and realize timely personalized diagnosis of tumor at molecular and cellular level, quantitatively dynamic monitoring of tumor, etc. This review introduces the basic concepts of multimodal molecular imaging, implementation methods and recent research progress of the applications in tumor diagnosis. The development trend of multimodal molecular imaging in tumor diagnosis is also prospected.
The multimodal molecular imaging technology integrates the advantages of variant imaging methods which can provide a more comprehensive and accurate information in cancer diagnosis, and realize timely personalized diagnosis of tumor at molecular and cellular level, quantitatively dynamic monitoring of tumor, etc. This review introduces the basic concepts of multimodal molecular imaging, implementation methods and recent research progress of the applications in tumor diagnosis. The development trend of multimodal molecular imaging in tumor diagnosis is also prospected.
2016, 44(10): 1619-1624
doi: 10.11895/j.issn.0253-3820.160267
Abstract:
A biofilm reactor (BFR) was fabricated via a cultivation process using naturally occurring microbial seeds from locally collected wastewaters, and a series of researches were carried out with this BFR based online Biochemical Oxygen Demand (BOD) monitor. The results showed that the BFR cultivation time was less than 14 h, and the biodegradation efficiencies was 18.5%. The minimum detection limit was 0.5 mg/L, as well as the upper detection limit was 20 mg/L. The relative error and relative standard deviation in accuracy and long term stability to standard were -0.8% and ±3.2%, respectively. The real sample determinations showed an average relative error of +5.6% to conventional BOD5 method. The BFR maintained a good performance in long term stability and accuracy during this test period, and the broad linear range ensured the demand for surface water online monitoring.
A biofilm reactor (BFR) was fabricated via a cultivation process using naturally occurring microbial seeds from locally collected wastewaters, and a series of researches were carried out with this BFR based online Biochemical Oxygen Demand (BOD) monitor. The results showed that the BFR cultivation time was less than 14 h, and the biodegradation efficiencies was 18.5%. The minimum detection limit was 0.5 mg/L, as well as the upper detection limit was 20 mg/L. The relative error and relative standard deviation in accuracy and long term stability to standard were -0.8% and ±3.2%, respectively. The real sample determinations showed an average relative error of +5.6% to conventional BOD5 method. The BFR maintained a good performance in long term stability and accuracy during this test period, and the broad linear range ensured the demand for surface water online monitoring.
2016, 44(10): 1625-1631
doi: 10.11895/j.issn.0253-3820.160130
Abstract:
The development and application of an on-line fast gas chromatography-quadrupole mass spectrometer (FGC-QMS) for logging technology were illustrated. The FGC was equipped with a suction pump to extract sample and a ten-way valve based on gas-driving for automatic sampling. The QMS with electron impact ion source and selected ion monitoring was used for detection of hydrocarbons in oil gas with high sensitivity and fast acquisition speed. The instrument could perform continuously cyclic sampling and analysis by a precise sequential controller, thus meeting the requirement for on-line detection. By using nitrogen as carrier gas, the analysis time of C1-C5 alkanes was less than 30 s and C1-C8 was less than 90 s by the instrument, at the same time, the detection limit was volume fraction 0.0001% and linear range exceeded 5 orders of magnitude, showing that the instrument was appropriate for the fast real-time detection of hydrocarbons of oil gas in well logging process.
The development and application of an on-line fast gas chromatography-quadrupole mass spectrometer (FGC-QMS) for logging technology were illustrated. The FGC was equipped with a suction pump to extract sample and a ten-way valve based on gas-driving for automatic sampling. The QMS with electron impact ion source and selected ion monitoring was used for detection of hydrocarbons in oil gas with high sensitivity and fast acquisition speed. The instrument could perform continuously cyclic sampling and analysis by a precise sequential controller, thus meeting the requirement for on-line detection. By using nitrogen as carrier gas, the analysis time of C1-C5 alkanes was less than 30 s and C1-C8 was less than 90 s by the instrument, at the same time, the detection limit was volume fraction 0.0001% and linear range exceeded 5 orders of magnitude, showing that the instrument was appropriate for the fast real-time detection of hydrocarbons of oil gas in well logging process.
