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2017 Volume 45 Issue 6
2017, 45(6): 785-790
doi: 10.11895/j.issn.0253-3820.160777
Abstract:
Based on the plasmon coupling effect in gold nanoparticles core-satellite nanostructures linked by thymine(T)-rich DNA hybridization and the specific Hg2+-mediated T-Hg2+-T base pair, a novel localized surface plasmon resonance (LSPR) optical fiber sensor was proposed and developed for Hg2+ detection in water. The Hg2+-induced conformational change in T-rich DNA sequence inhibited the DNA hybridization reaction, weakened the plasmon coupling effect and leaded to the change of LSPR resonance wavelength. The concentration of Hg2+ was quantitatively determined by the resonance wavelength redshift. The linear range of Hg2+ detection was about 5-150 nmol/L with LOD about 3.4 nmol/L. The specificity of the sensor was proved great by evaluating the response to other heavy metal ions such as Zn2+, Mg2+, Pb2+ and so on. This sensor was applied in environmental water detection by standard addition method,with the RSD less than 4.8% and recoveries of 94.2%-105.4%.
Based on the plasmon coupling effect in gold nanoparticles core-satellite nanostructures linked by thymine(T)-rich DNA hybridization and the specific Hg2+-mediated T-Hg2+-T base pair, a novel localized surface plasmon resonance (LSPR) optical fiber sensor was proposed and developed for Hg2+ detection in water. The Hg2+-induced conformational change in T-rich DNA sequence inhibited the DNA hybridization reaction, weakened the plasmon coupling effect and leaded to the change of LSPR resonance wavelength. The concentration of Hg2+ was quantitatively determined by the resonance wavelength redshift. The linear range of Hg2+ detection was about 5-150 nmol/L with LOD about 3.4 nmol/L. The specificity of the sensor was proved great by evaluating the response to other heavy metal ions such as Zn2+, Mg2+, Pb2+ and so on. This sensor was applied in environmental water detection by standard addition method,with the RSD less than 4.8% and recoveries of 94.2%-105.4%.
2017, 45(6): 791-798
doi: 10.11895/j.issn.0253-3820.170026
Abstract:
An acute myocardial infarction rat model was established by ligation of the left ventricular coronary artery. Plasma samples of rats were collected and analyzed by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) to study the myocardial protection mechanism of compound Danshen dropping pill (CDDP). After principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), 22 metabolites were identified as potential biomarker of AMI. Furthermore, CDDP had remarkable effect on AMI rats. p-Tolyl sulfate, hippuric acid, equol 7-O-glucuronide, lysoPC(16:0), cholic acid, oleamide, palmitic amide and SM(d18:1/16:0) were significantly changed in treatment group. The results showed that CDDP had a very good myocardial protection effect on AMI rats, and might influence the pathways of phenylalanine metabolism, glycerophospholipid metabolism, fatty acid metabolism, primary bile acid biosynthesis and Sphingolipid metabolism.
An acute myocardial infarction rat model was established by ligation of the left ventricular coronary artery. Plasma samples of rats were collected and analyzed by ultra performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC-QTOF/MS) to study the myocardial protection mechanism of compound Danshen dropping pill (CDDP). After principal component analysis (PCA) and partial least squares discriminant analysis (PLS-DA), 22 metabolites were identified as potential biomarker of AMI. Furthermore, CDDP had remarkable effect on AMI rats. p-Tolyl sulfate, hippuric acid, equol 7-O-glucuronide, lysoPC(16:0), cholic acid, oleamide, palmitic amide and SM(d18:1/16:0) were significantly changed in treatment group. The results showed that CDDP had a very good myocardial protection effect on AMI rats, and might influence the pathways of phenylalanine metabolism, glycerophospholipid metabolism, fatty acid metabolism, primary bile acid biosynthesis and Sphingolipid metabolism.
2017, 45(6): 799-808
doi: 10.11895/j.issn.0253-3820.170017
Abstract:
A method for determination of PCDD/Fs, PCBs and PCNs in soil sample was developed by using accelerated solvent extraction (ASE)-silica gel column cleanup-basic alumina column separation coupled with GC-MS/MS. The sample was extracted by ASE with Hexane-methylene chloride (Hex-DCM, 50:50, V/V) at 120℃. The basic alumina column was used to separate PCDD/Fs, PCBs and PCNs. The extracts were eluted with Hex-DCM (95:5, V/V) to obtain PCBs and PCNs, followed by Hex-DCM (50:50, V/V) to obtain PCDD/Fs. The limits of detection (LOD) were in the range of 0.04-0.25 μg/L, 0.10-0.20 μg/L and 0.01-0.05 μg/L for PCDD/Fs, PCBs, PCNs, respectively. The relative standard deviations (RSDs) of average relative response factors (RRF) were below 13%. The recoveries of 13C-labeled internal standards of the three classes of analytes were 50%-95%, 51%-103% and 49%-74%, respectively. Concentrations of ∑PCDD/Fs, ∑PCBs and ∑PCNs in soil samples were 16.1-1148 pg/g, 6.6-152.6 pg/g and 10.9-99.5 pg/g, respectively. The results were consistent with that of high resolution mass spectrometery
A method for determination of PCDD/Fs, PCBs and PCNs in soil sample was developed by using accelerated solvent extraction (ASE)-silica gel column cleanup-basic alumina column separation coupled with GC-MS/MS. The sample was extracted by ASE with Hexane-methylene chloride (Hex-DCM, 50:50, V/V) at 120℃. The basic alumina column was used to separate PCDD/Fs, PCBs and PCNs. The extracts were eluted with Hex-DCM (95:5, V/V) to obtain PCBs and PCNs, followed by Hex-DCM (50:50, V/V) to obtain PCDD/Fs. The limits of detection (LOD) were in the range of 0.04-0.25 μg/L, 0.10-0.20 μg/L and 0.01-0.05 μg/L for PCDD/Fs, PCBs, PCNs, respectively. The relative standard deviations (RSDs) of average relative response factors (RRF) were below 13%. The recoveries of 13C-labeled internal standards of the three classes of analytes were 50%-95%, 51%-103% and 49%-74%, respectively. Concentrations of ∑PCDD/Fs, ∑PCBs and ∑PCNs in soil samples were 16.1-1148 pg/g, 6.6-152.6 pg/g and 10.9-99.5 pg/g, respectively. The results were consistent with that of high resolution mass spectrometery
2017, 45(6): 809-816
doi: 10.11895/j.issn.0253-3820.160859
Abstract:
By combining frequency modulation Chirp Z transform ion mobility spectrometers (IMS) and multi nozzle electrospray array ionization source, a method of NanoESI-Chirp Z transform ion mobility spectrometry-high performance liquid chromatography was developed for the determination of n-alkyl ammonium bromide compounds. The parameters of NanoESI-Chirp Z transform IMS such as electric field intensity, solvent composition, and solution flow rate were investigated and optimized. Subsequently, four kinds of n-alkyl ammonium bromide compounds were respectively detected by this developed Chirp Z transform method and Fourier transform method, and the obtained results were compared. The result indicated that the optimum conditions were electric field intensity of 4.5 kV, and ESI solution flow rate of 8 μL/min. Then a test mixture containing tetrabutylammonium bromide, tetrapentylammoniumbromide, tetrahexylammonium bromide, tetraheptylammonium bromide, tetranoctylammoniumbromideandtetrakis(decyl) ammonium bromide was successfully separated and determined by the HPLC-nanoESI-Chirp Z IMS method.Chirp Z transform method provided higher signal to noise ratio compared to conventional signal averaging method, and was superior to FT method in the determination of drift time.
By combining frequency modulation Chirp Z transform ion mobility spectrometers (IMS) and multi nozzle electrospray array ionization source, a method of NanoESI-Chirp Z transform ion mobility spectrometry-high performance liquid chromatography was developed for the determination of n-alkyl ammonium bromide compounds. The parameters of NanoESI-Chirp Z transform IMS such as electric field intensity, solvent composition, and solution flow rate were investigated and optimized. Subsequently, four kinds of n-alkyl ammonium bromide compounds were respectively detected by this developed Chirp Z transform method and Fourier transform method, and the obtained results were compared. The result indicated that the optimum conditions were electric field intensity of 4.5 kV, and ESI solution flow rate of 8 μL/min. Then a test mixture containing tetrabutylammonium bromide, tetrapentylammoniumbromide, tetrahexylammonium bromide, tetraheptylammonium bromide, tetranoctylammoniumbromideandtetrakis(decyl) ammonium bromide was successfully separated and determined by the HPLC-nanoESI-Chirp Z IMS method.Chirp Z transform method provided higher signal to noise ratio compared to conventional signal averaging method, and was superior to FT method in the determination of drift time.
2017, 45(6): 817-823
doi: 10.11895/j.issn.0253-3820.170001
Abstract:
The types and relative content difference of the toxic peptides in twelve species of Amanita were evaluated by the high performance liquid chromatography (HPLC) and ultra performnace liquid chromatography-electrospray-quadrupole-time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS). The efficient toxic compounds in mushroom were extracted using 50% methanol in water containing 0.5% formic acid. Then, separation of various components in mushroom was carried out using Agilent 300 Extend-C18 column with 0.05% (V/V) trifluoroacetic acid in 20 mmol/L ammonium acetate-methanol as mobile phase under a gradient program. The results indicated the significant difference in types and relative content of toxic peptides among all investigated mushrooms. In addition, we generated a chromatographic fingerprint based on the toxic peptide profiles. Finally 19 compositions were detected in the Amanita species, including 13 Amanita toxic peptides, 5 unknown toxic peptides and 1 unknown compound. These results play an important role in the discrimination of different Amanita species, and provide evidence in prevention and diagnosis of Amanitin poisoned events.
The types and relative content difference of the toxic peptides in twelve species of Amanita were evaluated by the high performance liquid chromatography (HPLC) and ultra performnace liquid chromatography-electrospray-quadrupole-time-of-flight-mass spectrometry (HPLC-ESI-QTOF-MS). The efficient toxic compounds in mushroom were extracted using 50% methanol in water containing 0.5% formic acid. Then, separation of various components in mushroom was carried out using Agilent 300 Extend-C18 column with 0.05% (V/V) trifluoroacetic acid in 20 mmol/L ammonium acetate-methanol as mobile phase under a gradient program. The results indicated the significant difference in types and relative content of toxic peptides among all investigated mushrooms. In addition, we generated a chromatographic fingerprint based on the toxic peptide profiles. Finally 19 compositions were detected in the Amanita species, including 13 Amanita toxic peptides, 5 unknown toxic peptides and 1 unknown compound. These results play an important role in the discrimination of different Amanita species, and provide evidence in prevention and diagnosis of Amanitin poisoned events.
2017, 45(6): 824-829
doi: 10.11895/j.issn.0253-3820.160855
Abstract:
A fluorescence nanosensor based on an easily prepared fluorescent molecule, 1-oxo-1H-phenalene-2,3-dicarbonitrile (OPD), was developed for highly sensitive detection of glucose. Under the catalysis of horseradish peroxidase (HRP), 3,3',5,5'-tetramethylbenzidine (TMB) was oxidized into oxidized TMB (oxTMB) by H2O2. And the fluorescence of OPD was quenched by the intense absorption of the formed oxTMB, thus realizing effective quantitative detection of H2O2. The linear range was 0.05-0.8 μmol/L and 1-10 μmol/L respectively, with limit of detection of 0.02 μmol/L. Besides, on the basis of transformation of glucose into H2O2 through the catalysis of glucose oxidase, this nanosensor could be further exploited for highly sensitive detection of glucose. The TMB-HRP-OPD sensor exhibited linear range of 0.1-3.0 μmol/L and 4.0-30 μmol/L respectively for detection of glucose, with limit of detection of 0.02 μmol/L. Furthermore, it was successfully applied to the determination of glucose in real human serum and the results were in good agreement with the clinical data
A fluorescence nanosensor based on an easily prepared fluorescent molecule, 1-oxo-1H-phenalene-2,3-dicarbonitrile (OPD), was developed for highly sensitive detection of glucose. Under the catalysis of horseradish peroxidase (HRP), 3,3',5,5'-tetramethylbenzidine (TMB) was oxidized into oxidized TMB (oxTMB) by H2O2. And the fluorescence of OPD was quenched by the intense absorption of the formed oxTMB, thus realizing effective quantitative detection of H2O2. The linear range was 0.05-0.8 μmol/L and 1-10 μmol/L respectively, with limit of detection of 0.02 μmol/L. Besides, on the basis of transformation of glucose into H2O2 through the catalysis of glucose oxidase, this nanosensor could be further exploited for highly sensitive detection of glucose. The TMB-HRP-OPD sensor exhibited linear range of 0.1-3.0 μmol/L and 4.0-30 μmol/L respectively for detection of glucose, with limit of detection of 0.02 μmol/L. Furthermore, it was successfully applied to the determination of glucose in real human serum and the results were in good agreement with the clinical data
2017, 45(6): 830-836
doi: 10.11895/j.issn.0253-3820.170022
Abstract:
A large-area graphene platform electrode (GPE) was fabricated by transferring the chemical vapor deposition (CVD) graphene grown on Cu foils to polyethylene terephthalate (PET) substrates with the aid of polymethyl-methacrylate (PMMA). Then cobalt hexacyanoferrate (CoHCF) was electrodeposited on the GPE by cyclic voltammetry to obtain a CoHCF/GPE. The morphology and electrochemical properties of this electrode were studied by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and the electrochemical measurements. Results showed that the electrode had favorable sensing effect toward H2O2. On the basis of this, a new nonenzyme H2O2 sensor was constructed. Under the optimal experimental conditions, the proposed sensor had a quick response to the addition of H2O2 (about 2 s) with a wide linear rang (5×10-3-1.2 mmol/L) and a low detection limit (7.1 nmol/L). This sensor was easy to fabricate and showed excellent stability and anti-interference ability.
A large-area graphene platform electrode (GPE) was fabricated by transferring the chemical vapor deposition (CVD) graphene grown on Cu foils to polyethylene terephthalate (PET) substrates with the aid of polymethyl-methacrylate (PMMA). Then cobalt hexacyanoferrate (CoHCF) was electrodeposited on the GPE by cyclic voltammetry to obtain a CoHCF/GPE. The morphology and electrochemical properties of this electrode were studied by scanning electron microscope (SEM), electrochemical impedance spectroscopy (EIS) and the electrochemical measurements. Results showed that the electrode had favorable sensing effect toward H2O2. On the basis of this, a new nonenzyme H2O2 sensor was constructed. Under the optimal experimental conditions, the proposed sensor had a quick response to the addition of H2O2 (about 2 s) with a wide linear rang (5×10-3-1.2 mmol/L) and a low detection limit (7.1 nmol/L). This sensor was easy to fabricate and showed excellent stability and anti-interference ability.
2017, 45(6): 837-843
doi: 10.11895/j.issn.0253-3820.170184
Abstract:
A rapid gas chromatography-tandem mass spectrometric (GC-MS) method was developed for the analysis of alkaline and neutral volatile metabolites of human and rat feces. Feces were extracted by 75% (V/V) methanol solution. After addition of ammonia solution (pH 10, final concentration of 1%), the supernatant was subjected to GC-MS analysis. In the experiment, a CP-Sil 5 (25 m×0.25 mm×0.12 μm) capillary column was utilized to separate the interesting compounds. Helium was employed as a carrier gas at a constant flow rate of 1 mL/min. Oven temperature was programmed as follows:the initial temperature was set at 50℃ and held for 1 min, then increased at 25℃/min to 150℃, sustained for 1 min; increased at 20℃/min to 200℃, held for 2 min; and finally increased at 10℃/min to 270℃, maintained for 5 min. The MS was operated in the electron impact ionization mode at -70 eV. The injector, ion source and transfer line temperatures were maintained at 220℃, 230℃ and 280℃, respectively. Mass data were acquired in full scan mode from m/z 10 to 600. The solvent delay time was set for 3 min. A total of 11 volatile components were identified in the feces from human and 7 in the feces from rats by retrieving the NIST library, comparing with the standards and analyzing the MS data. The method was simple and sensitive in the detection of alkaline and neutral volatile metabolites of feces from human and rats.
A rapid gas chromatography-tandem mass spectrometric (GC-MS) method was developed for the analysis of alkaline and neutral volatile metabolites of human and rat feces. Feces were extracted by 75% (V/V) methanol solution. After addition of ammonia solution (pH 10, final concentration of 1%), the supernatant was subjected to GC-MS analysis. In the experiment, a CP-Sil 5 (25 m×0.25 mm×0.12 μm) capillary column was utilized to separate the interesting compounds. Helium was employed as a carrier gas at a constant flow rate of 1 mL/min. Oven temperature was programmed as follows:the initial temperature was set at 50℃ and held for 1 min, then increased at 25℃/min to 150℃, sustained for 1 min; increased at 20℃/min to 200℃, held for 2 min; and finally increased at 10℃/min to 270℃, maintained for 5 min. The MS was operated in the electron impact ionization mode at -70 eV. The injector, ion source and transfer line temperatures were maintained at 220℃, 230℃ and 280℃, respectively. Mass data were acquired in full scan mode from m/z 10 to 600. The solvent delay time was set for 3 min. A total of 11 volatile components were identified in the feces from human and 7 in the feces from rats by retrieving the NIST library, comparing with the standards and analyzing the MS data. The method was simple and sensitive in the detection of alkaline and neutral volatile metabolites of feces from human and rats.
2017, 45(6): 844-850
doi: 10.11895/j.issn.0253-3820.170029
Abstract:
Subcritical butane technology was employed for the separation of abamectin on the fresh tea leaves surface. Under the conditions of solid-liquid ratio of 1:10 (m/V), the experiment was designed via the response surface methodology and conducted at different temperature, various separation time and discrepant cycle number. Besides, the activity of the polyphenol oxidase (PPO) relating to the quality of the tea was determined and compared. At the same time, scanning electron microscopy (SEM) was used to observe the surface structure of fresh tea leaves before and after treatment, and the effect on physiological characteristics of the leaves by subcritical butane treatment was analyzed. The experimental results showed that the subcritical butane extraction could effectively isolate the abamectin, making the physical structure basically remained and the polyphenol oxidase activity preserved as well. Through the analysis by Design Expert software, the optimal processing parameters of separating abamectin were as follows:45℃, 30 min, 1 cycle, and solid-liquid ratio of 1:10 (m/V). Under the optimal conditions, the separation efficiency was over 91% and the relative PPO activity was 25.73%. The structure of fresh tea leaves changed insignificantly before and after the butane processing. This study suggested that the subcritical butane extraction technology could effectively remove pesticide residues in tea, thus provided a certain scientific basis for application of subcritical fluid removal of pesticide residue in natural plants.
Subcritical butane technology was employed for the separation of abamectin on the fresh tea leaves surface. Under the conditions of solid-liquid ratio of 1:10 (m/V), the experiment was designed via the response surface methodology and conducted at different temperature, various separation time and discrepant cycle number. Besides, the activity of the polyphenol oxidase (PPO) relating to the quality of the tea was determined and compared. At the same time, scanning electron microscopy (SEM) was used to observe the surface structure of fresh tea leaves before and after treatment, and the effect on physiological characteristics of the leaves by subcritical butane treatment was analyzed. The experimental results showed that the subcritical butane extraction could effectively isolate the abamectin, making the physical structure basically remained and the polyphenol oxidase activity preserved as well. Through the analysis by Design Expert software, the optimal processing parameters of separating abamectin were as follows:45℃, 30 min, 1 cycle, and solid-liquid ratio of 1:10 (m/V). Under the optimal conditions, the separation efficiency was over 91% and the relative PPO activity was 25.73%. The structure of fresh tea leaves changed insignificantly before and after the butane processing. This study suggested that the subcritical butane extraction technology could effectively remove pesticide residues in tea, thus provided a certain scientific basis for application of subcritical fluid removal of pesticide residue in natural plants.
2017, 45(6): 851-855
doi: 10.11895/j.issn.0253-3820.170112
Abstract:
Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) has become an indispensable tool in macromolecule and small molecule analysis for solid and liquid samples. However, there were few studies focusing on the ionization mechanisms especially for the small molecules. In this work, the compounds of pyrene, coronene and rubrene which have similar molecular structures were used to investigate the ionization mechanism via SALDI-MS. Additionally the effect of the laser power on the product ions was also investigated. It was found that strong cluster ions peaks nM+(M=pyrene, coronene) were observed for pyrene and coronene, and daughter ions of coronene by loss of C2H2 were also observed. On the contrary, no cluster ion was obtained for rubrene, only daughter ions with the losses of nC6H5 (n=1, 2, 3) were acquired. Finally, the ionization mechanisms were discussed. The formation of clusters of pyrene and coronene was attributed to the interaction of π-π bands. For rubrene, the spatial barrier weakened the interaction of π-π bands because the four phenyl groups were not on the same plane of skeleton structure, thus impeding the formation of cluster ions.
Surface-assisted laser desorption/ionization mass spectrometry (SALDI-MS) has become an indispensable tool in macromolecule and small molecule analysis for solid and liquid samples. However, there were few studies focusing on the ionization mechanisms especially for the small molecules. In this work, the compounds of pyrene, coronene and rubrene which have similar molecular structures were used to investigate the ionization mechanism via SALDI-MS. Additionally the effect of the laser power on the product ions was also investigated. It was found that strong cluster ions peaks nM+(M=pyrene, coronene) were observed for pyrene and coronene, and daughter ions of coronene by loss of C2H2 were also observed. On the contrary, no cluster ion was obtained for rubrene, only daughter ions with the losses of nC6H5 (n=1, 2, 3) were acquired. Finally, the ionization mechanisms were discussed. The formation of clusters of pyrene and coronene was attributed to the interaction of π-π bands. For rubrene, the spatial barrier weakened the interaction of π-π bands because the four phenyl groups were not on the same plane of skeleton structure, thus impeding the formation of cluster ions.
2017, 45(6): 856-861
doi: 10.11895/j.issn.0253-3820.170004
Abstract:
A method of metal organic nanotubes-based dispersive solid phase extraction-gas chromatography-tandem mass spectrometry was developed for sensitive analysis of polychlorinated biphenyls in environmental water samples. Related important factors influencing enrichment efficiency, such as ionic strength, extraction time and amount of adsorbent, were investigated. Response surface methodology was used to optimize these factors in detail. Under the optimal conditions such as 4.92% (w/V) NaCl, 4.5 min of extraction time, 62.5 mg of adsorbent, and n-hexane as desorption solvent, wide linearity (2-1000 ng/L or 5-1000 ng/L), and low limits of detection (0.26-0.82 ng/L) were achieved. The intra-day and inter-day relative standard deviations were 0.8%-5.5% (200 ng/L, n=6)and 2.7%-7.4% (200 ng/L, n=6), respectively. Finally, this method was successfully applied to the sensitive analysis of 6 kinds of PCBs in environmental water samples, with satisfactory recoveries of 78.9%-113.3%.
A method of metal organic nanotubes-based dispersive solid phase extraction-gas chromatography-tandem mass spectrometry was developed for sensitive analysis of polychlorinated biphenyls in environmental water samples. Related important factors influencing enrichment efficiency, such as ionic strength, extraction time and amount of adsorbent, were investigated. Response surface methodology was used to optimize these factors in detail. Under the optimal conditions such as 4.92% (w/V) NaCl, 4.5 min of extraction time, 62.5 mg of adsorbent, and n-hexane as desorption solvent, wide linearity (2-1000 ng/L or 5-1000 ng/L), and low limits of detection (0.26-0.82 ng/L) were achieved. The intra-day and inter-day relative standard deviations were 0.8%-5.5% (200 ng/L, n=6)and 2.7%-7.4% (200 ng/L, n=6), respectively. Finally, this method was successfully applied to the sensitive analysis of 6 kinds of PCBs in environmental water samples, with satisfactory recoveries of 78.9%-113.3%.
2017, 45(6): 862-867
doi: 10.11895/j.issn.0253-3820.170131
Abstract:
Based on the plasma activation and the sensing ability of cataluminescence, a low temperature plasma-assisted cataluminescence sensor was developed for ethylene detection using the low-cost and abundant alkaline-earth oxides of MgO nanomaterials as the sensing materials. Taking advantage of the high activity of the plasma, the working temperature of this method was greatly decreased than that of traditional detection method (300-500℃), and the sensing of ethylene was realized at room temperature without any heating device. This ethylene cataluminescence sensor gave a linear range of 112-4997 ng/mL (90-3998 ppm, R=0.97669) with a detection limit of 37 ng/mL (30 ppm). Besides, the sensor showed good selectivity and stability in ethylene detection. Due to the absence of the heating element, the present sensor was simple, rapid, low-cost, low energy-consumption and stable for ethylene sensing. This study improved the applicability of cataluminescence sensors and might promote the development of cataluminescence sensors.
Based on the plasma activation and the sensing ability of cataluminescence, a low temperature plasma-assisted cataluminescence sensor was developed for ethylene detection using the low-cost and abundant alkaline-earth oxides of MgO nanomaterials as the sensing materials. Taking advantage of the high activity of the plasma, the working temperature of this method was greatly decreased than that of traditional detection method (300-500℃), and the sensing of ethylene was realized at room temperature without any heating device. This ethylene cataluminescence sensor gave a linear range of 112-4997 ng/mL (90-3998 ppm, R=0.97669) with a detection limit of 37 ng/mL (30 ppm). Besides, the sensor showed good selectivity and stability in ethylene detection. Due to the absence of the heating element, the present sensor was simple, rapid, low-cost, low energy-consumption and stable for ethylene sensing. This study improved the applicability of cataluminescence sensors and might promote the development of cataluminescence sensors.
2017, 45(6): 868-873
doi: 10.11895/j.issn.0253-3820.170052
Abstract:
The ablated aerosols of biological matrix sample were studied using 213 nm nanosecond laser ablation system. The stable signal intensity and high sensitivity were obtained when the laser energy was 25%, the spot size was 200 μm, the scan rate was 20 μm/s, the frequency was 20 Hz and the carrier gas was 700 mL He + 700 mL Ar. Relative fractionation index of 56 elements were investigated and 31P as the internal standard element was selected under the optimized laser ablation conditions. The results showed that particle size of the biological sample was 3 μm, which was larger compared with NIST 610 sample. Element fractionation in biological sample was smaller than in glass sample, and relative fractionation index of most elements attained 1.0±0.1. Element fractionation mechanism of biological sample was discussed. The possible reason why the relative fractionation index in biological sample with large particle size did not significantly increase compared to the glass sample is that the 3-μm particles entered into ICP can be atomized. On the other hand, enrichment effect for large ablation particles was relatively small. Further study of the influence factors of fractionation effect indicated that, the fractionation effect had relations with laser ablation energy, laser frequency and scan rate, negatively relation with the oxide boiling point, and positively relation with oxide bond energy and ionization energy.
The ablated aerosols of biological matrix sample were studied using 213 nm nanosecond laser ablation system. The stable signal intensity and high sensitivity were obtained when the laser energy was 25%, the spot size was 200 μm, the scan rate was 20 μm/s, the frequency was 20 Hz and the carrier gas was 700 mL He + 700 mL Ar. Relative fractionation index of 56 elements were investigated and 31P as the internal standard element was selected under the optimized laser ablation conditions. The results showed that particle size of the biological sample was 3 μm, which was larger compared with NIST 610 sample. Element fractionation in biological sample was smaller than in glass sample, and relative fractionation index of most elements attained 1.0±0.1. Element fractionation mechanism of biological sample was discussed. The possible reason why the relative fractionation index in biological sample with large particle size did not significantly increase compared to the glass sample is that the 3-μm particles entered into ICP can be atomized. On the other hand, enrichment effect for large ablation particles was relatively small. Further study of the influence factors of fractionation effect indicated that, the fractionation effect had relations with laser ablation energy, laser frequency and scan rate, negatively relation with the oxide boiling point, and positively relation with oxide bond energy and ionization energy.
2017, 45(6): 874-882
doi: 10.11895/j.issn.0253-3820.160916
Abstract:
β-Cyclodextrin-N-vinyl-2-pyrrolidone (CDM-NVP) copolymer was prepared by free radical chain reaction of N-vinyl-2-pyrrolidone (NVP) and β-CD maleate (CDM) with γ-ray as initiator. The synthesis conditions of CDM-NVP polymer were as follows:mass ratio of CDM to NVP was 1:0.7 (CDM 3.6 g and NVP 2.52 g), irradiation dosage was 4 kGy, and DMF aqueous solution (50%, V/V) was set at 20 mL. Under the synthesis conditions, the yield of CDM-NVP was 84% and the weight-average molecular weight was 20 kD. The natamycin (NM) and carbendazim (MBC) could form stable inclusion complexes with CDM-NVP copolymer, and the solubility and fungicidal activity of the complexes were investigated. The stability constant of NM·CDM-NVP and MBC·CDM-NVP complexes at 303 K were 12, 988.54 L/mol and 865.94 L/mol, respectively. The complexes were characterized using phase solubility diagrams, nuclear magnetic resonance (NMR) spectra and ultraviolet (UV) spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone.
β-Cyclodextrin-N-vinyl-2-pyrrolidone (CDM-NVP) copolymer was prepared by free radical chain reaction of N-vinyl-2-pyrrolidone (NVP) and β-CD maleate (CDM) with γ-ray as initiator. The synthesis conditions of CDM-NVP polymer were as follows:mass ratio of CDM to NVP was 1:0.7 (CDM 3.6 g and NVP 2.52 g), irradiation dosage was 4 kGy, and DMF aqueous solution (50%, V/V) was set at 20 mL. Under the synthesis conditions, the yield of CDM-NVP was 84% and the weight-average molecular weight was 20 kD. The natamycin (NM) and carbendazim (MBC) could form stable inclusion complexes with CDM-NVP copolymer, and the solubility and fungicidal activity of the complexes were investigated. The stability constant of NM·CDM-NVP and MBC·CDM-NVP complexes at 303 K were 12, 988.54 L/mol and 865.94 L/mol, respectively. The complexes were characterized using phase solubility diagrams, nuclear magnetic resonance (NMR) spectra and ultraviolet (UV) spectra. The analysis of the biological activities of these two complexes indicated that they possessed enhancing fungicidal activities compared to NM and MBC alone.
2017, 45(6): 883-888
doi: 10.11895/j.issn.0253-3820.170088
Abstract:
Yttrium vanadate:europium nanoprobes (YVO4:Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method. Due to the overlapping of the excitation spectrum of YVO4:Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4:Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4:Eu NPs was quenched. Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4:Eu as nanoprobes based on IFE. Some experimental parameters, such as the adding amount of YVO4:Eu NPs, pH value of the reacting solution, and reacting time, were investigated. Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×10-4 mol/L and the detection limit was 1.0×10-6 mol/L (3σ). The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%. This method is simple, rapid, sensitive and accurate.
Yttrium vanadate:europium nanoprobes (YVO4:Eu NPs) with good fluorescence properties and water solubility were synthesized by solvent thermal method. Due to the overlapping of the excitation spectrum of YVO4:Eu NPs and the absorption spectrum of tryptophan, fluorescent internal filter effect (IFE) occurred, in which YVO4:Eu NPs were the fluorophore and tryptophan was the absorber, leading the fluorescence of YVO4:Eu NPs was quenched. Therefore, a new method for the determination of tryptophan was established by using fluorescent YVO4:Eu as nanoprobes based on IFE. Some experimental parameters, such as the adding amount of YVO4:Eu NPs, pH value of the reacting solution, and reacting time, were investigated. Under the optimum reaction conditions, the linear range of the method was 4.0×10-6-4.0×10-4 mol/L and the detection limit was 1.0×10-6 mol/L (3σ). The content of tryptophan in the soy sauce was determined with the recovery of 95.2% and 97.3%. This method is simple, rapid, sensitive and accurate.
2017, 45(6): 889-897
doi: 10.11895/j.issn.0253-3820.170050
Abstract:
High-affinity α-glucosidase inhibitors were screened from Cichorium glundulosum Boiss.et Hout seed (CGS) extract by ultra-filtration affinity-liquid chromatography-mass spectrometry (UF-LC-MS) and molecular docking. By taking 4-nitrobenzene-α-D-glucopyranoside (PNPG) as substrate and acarbose as positive control to evaluate the inhibitory activity of CGS extract, IC50 of acarbose and CGS extract were 0.003 mg/mL and 0.447 mg/mL, respectively. Meanwhile, 4 compounds from CGS extract by UF-LC-MS were screened and identified. Then by using autodock software, the compounds that combined with α-glucosidase were well screened out, including chlorogenic acid and isochlorogenic acid A. The inhibitory activity of chlorogenic acid and chlorogenic acid A against α-glucosidase was verified in vitro. The results showed that the inhibitory activity of the compounds toward α-glucosidase presented the sequence of acarbose> isochlorogenic acid A> chlorogenic acid. The inhibition rate of isochlorogenic acid A was close to acarbose. The experimental results illustrated that UF-LC-MS and molecular docking could be used to screen high affinity enzyme inhibitors from CGS.
High-affinity α-glucosidase inhibitors were screened from Cichorium glundulosum Boiss.et Hout seed (CGS) extract by ultra-filtration affinity-liquid chromatography-mass spectrometry (UF-LC-MS) and molecular docking. By taking 4-nitrobenzene-α-D-glucopyranoside (PNPG) as substrate and acarbose as positive control to evaluate the inhibitory activity of CGS extract, IC50 of acarbose and CGS extract were 0.003 mg/mL and 0.447 mg/mL, respectively. Meanwhile, 4 compounds from CGS extract by UF-LC-MS were screened and identified. Then by using autodock software, the compounds that combined with α-glucosidase were well screened out, including chlorogenic acid and isochlorogenic acid A. The inhibitory activity of chlorogenic acid and chlorogenic acid A against α-glucosidase was verified in vitro. The results showed that the inhibitory activity of the compounds toward α-glucosidase presented the sequence of acarbose> isochlorogenic acid A> chlorogenic acid. The inhibition rate of isochlorogenic acid A was close to acarbose. The experimental results illustrated that UF-LC-MS and molecular docking could be used to screen high affinity enzyme inhibitors from CGS.
2017, 45(6): 898-905
doi: 10.11895/j.issn.0253-3820.160912
Abstract:
A novel method based on cross sensitivity of cataluminescence (CTL) on nano-Ti3CeY2O11 was proposed for simultaneous determination of formaldehyde, benzene and sulfur dioxide in air. The relations between the concentrations of formaldehyde, benzene and sulfur dioxide and their CTL intensities were respectively ascertained at three wavelengths. The accurate concentrations of formaldehyde, benzene and sulfur dioxide can be calculated by superimposed total CTL intensities. The three analysis wavelengths are 420 nm, 535 nm and 680 nm. The surface temperature of the sensitive materials is 280℃. The carrier gas flow rate is 130 mL/min. The detection limits (3σ) are 0.04 mg/m3 for formaldehyde, 0.05 mg/m3 for benzene and 0.10 mg/m3 for sulfur dioxide, respectively. The linear ranges of CTL intensity versus analyte concentration are 0.08-75.60 mg/m3 for formaldehyde, 0.1-101.40 mg/m3 for benzene and 0.3 to 115.00 mg/m3 for sulfur dioxide. The recoveries of 12 testing standard samples by this method are 96.4%-103.7% for formaldehyde, 97.8%-102.5% for benzene and 97.2%-103.3% for sulfur dioxide. Common coexisting substances, such as acetaldehyde, toluene, hydrogen sulfide, ammonia, methanol, ethanol and carbon dioxide, do not disturb the determination. The relative deviation of CTL signals of continuous 200 h detection for gaseous mixture containing formaldehyde, benzene and sulfur dioxide is less than 2%, which shows the longevity of the nanometer composite oxide to formaldehyde, benzene and sulfur dioxide. This method makes full use of the cross sensitive phenomenon, and can realize the on-line analysis of formaldehyde, benzene and sulfur dioxide in air.
A novel method based on cross sensitivity of cataluminescence (CTL) on nano-Ti3CeY2O11 was proposed for simultaneous determination of formaldehyde, benzene and sulfur dioxide in air. The relations between the concentrations of formaldehyde, benzene and sulfur dioxide and their CTL intensities were respectively ascertained at three wavelengths. The accurate concentrations of formaldehyde, benzene and sulfur dioxide can be calculated by superimposed total CTL intensities. The three analysis wavelengths are 420 nm, 535 nm and 680 nm. The surface temperature of the sensitive materials is 280℃. The carrier gas flow rate is 130 mL/min. The detection limits (3σ) are 0.04 mg/m3 for formaldehyde, 0.05 mg/m3 for benzene and 0.10 mg/m3 for sulfur dioxide, respectively. The linear ranges of CTL intensity versus analyte concentration are 0.08-75.60 mg/m3 for formaldehyde, 0.1-101.40 mg/m3 for benzene and 0.3 to 115.00 mg/m3 for sulfur dioxide. The recoveries of 12 testing standard samples by this method are 96.4%-103.7% for formaldehyde, 97.8%-102.5% for benzene and 97.2%-103.3% for sulfur dioxide. Common coexisting substances, such as acetaldehyde, toluene, hydrogen sulfide, ammonia, methanol, ethanol and carbon dioxide, do not disturb the determination. The relative deviation of CTL signals of continuous 200 h detection for gaseous mixture containing formaldehyde, benzene and sulfur dioxide is less than 2%, which shows the longevity of the nanometer composite oxide to formaldehyde, benzene and sulfur dioxide. This method makes full use of the cross sensitive phenomenon, and can realize the on-line analysis of formaldehyde, benzene and sulfur dioxide in air.
2017, 45(6): 906-913
doi: 10.11895/j.issn.0253-3820.170023
Abstract:
In this work, band gap edge effect of photonic crystal (PC) was combined with gold nanoparticles (AuNPs) to fabricate a novel surface enhanced Raman scattering (SERS) substrate (PC-AuNPs). The preparation of PC-AuNPs substrate consisted of three steps. Firstly, SiO2 nanospheres were amino-modified. Then, an opal PC structure was obtained by vertical deposition of SiO2 nanospheres. Finally, AuNPs were loaded on the surface of opal structure. The Raman scattering signal of Rhodamine B (RhB) was detected on PC-AuNPs to evaluate the merits of this new substrate. It was found that the band gap range of photonic crystal and the loading amount of AuNPs were important factors for PC-AuNPs. A good linearity relationship could be obtained between the characteristic peak intensity of RhB and its logarithmic concentration (I=1711lg[RhB (mol/L)]+15244, R2=0.9994). The detection limit reached 1×10-8 mol/L. This method was simple and exhibited good sensitivity and reproducibility for Raman scattering detection, and could provide a novel strategy for the development of SERS substrate.
In this work, band gap edge effect of photonic crystal (PC) was combined with gold nanoparticles (AuNPs) to fabricate a novel surface enhanced Raman scattering (SERS) substrate (PC-AuNPs). The preparation of PC-AuNPs substrate consisted of three steps. Firstly, SiO2 nanospheres were amino-modified. Then, an opal PC structure was obtained by vertical deposition of SiO2 nanospheres. Finally, AuNPs were loaded on the surface of opal structure. The Raman scattering signal of Rhodamine B (RhB) was detected on PC-AuNPs to evaluate the merits of this new substrate. It was found that the band gap range of photonic crystal and the loading amount of AuNPs were important factors for PC-AuNPs. A good linearity relationship could be obtained between the characteristic peak intensity of RhB and its logarithmic concentration (I=1711lg[RhB (mol/L)]+15244, R2=0.9994). The detection limit reached 1×10-8 mol/L. This method was simple and exhibited good sensitivity and reproducibility for Raman scattering detection, and could provide a novel strategy for the development of SERS substrate.
2017, 45(6): 914-921
doi: 10.11895/j.issn.0253-3820.160842
Abstract:
To determine the Minbei Shuixian tea from different region quickly and non-destructively, proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS) was used to obtain chemical fingerprints of the volatile compounds of 113 samples directly from the surface of the dry tea leaves without any sample pretreatment in three regions (Wuyishan, Jianyang and Jian'ou). The raw MS data were analyzed by multivariate analysis, including principal component analysis (PCA) and analysis of variance (ANOVA). In addition, soft independent modeling class analogy (SIMCA), K nearest neighbor algorithm (KNN) and partial least squares discriminant analysis (PLS-DA) were used for pattern recognition. The experimental results demonstrated that in the positive ion mode, PTR-TOF-MS combined with multivariate analysis could effectively distinguish tea from different regions. Three principal components were extracted by PCA, and their cumulative contribution rate was 84.66%. The correct rates of the three sets of calibration models were 89.38%, 100.00%, 100.00%, and the accuracy rates of the prediction set were 83.18%, 96.46%, 95.57%, respectively. The different region pattern recognition model were successfully established. It was found that Shuixian tea in different regions of northern Fujian could be differentiated by PTR-TOF-MS and the results provided a basis for establishing a fast, non-destructive and sensitive detection method of tea, which could provide reference for geographical traceability.
To determine the Minbei Shuixian tea from different region quickly and non-destructively, proton transfer reaction-time of flight-mass spectrometry (PTR-TOF-MS) was used to obtain chemical fingerprints of the volatile compounds of 113 samples directly from the surface of the dry tea leaves without any sample pretreatment in three regions (Wuyishan, Jianyang and Jian'ou). The raw MS data were analyzed by multivariate analysis, including principal component analysis (PCA) and analysis of variance (ANOVA). In addition, soft independent modeling class analogy (SIMCA), K nearest neighbor algorithm (KNN) and partial least squares discriminant analysis (PLS-DA) were used for pattern recognition. The experimental results demonstrated that in the positive ion mode, PTR-TOF-MS combined with multivariate analysis could effectively distinguish tea from different regions. Three principal components were extracted by PCA, and their cumulative contribution rate was 84.66%. The correct rates of the three sets of calibration models were 89.38%, 100.00%, 100.00%, and the accuracy rates of the prediction set were 83.18%, 96.46%, 95.57%, respectively. The different region pattern recognition model were successfully established. It was found that Shuixian tea in different regions of northern Fujian could be differentiated by PTR-TOF-MS and the results provided a basis for establishing a fast, non-destructive and sensitive detection method of tea, which could provide reference for geographical traceability.
2017, 45(6): 922-930
doi: 10.11895/j.issn.0253-3820.170055
Abstract:
The fabrication system for the electrochemical microfluidic device was set up based on the pulse driving and controlling of microfluids technology. The nano silver ink and glycerol solution were jetted on the glass substrates to form the microelectrode pattern and the liquid mold pattern for the microchannel. Then the microelectrode and microchannel were obtained through a sintering process and a molding process, respectively. The electrochemical mircrofluidic device was Finally prepared through a bonding process with the microelectrode and the microchannel. The influences of the system parameters on the formation of the droplet were studied, as well as the influences of the droplets diameter and the overlap on the formation of the liquid lines. The minimal width, the thickness and the resistance of the prepared microelectrode were 45 μm, 2.2 μm and 5.2 μΩ cm, respectively. The minimal width of the microelectrode was 35 μm and the surface was smooth. The electrochemical flow detection of glucose concentration was carried out with the device, and the results showed that the glucose concentration had a high linear correlation with the response current, which could be used in the quantitative detection of glucose concentration. The fabrication of the electrochemical microfluidic device based on the pulse driving and controlling of micro fluids technology has many advantages such as simple system structure, lower cost and higher accuracy of the micro droplet and can be used in the preparation of the devices in the biochemical analysis and biosensor areas.
The fabrication system for the electrochemical microfluidic device was set up based on the pulse driving and controlling of microfluids technology. The nano silver ink and glycerol solution were jetted on the glass substrates to form the microelectrode pattern and the liquid mold pattern for the microchannel. Then the microelectrode and microchannel were obtained through a sintering process and a molding process, respectively. The electrochemical mircrofluidic device was Finally prepared through a bonding process with the microelectrode and the microchannel. The influences of the system parameters on the formation of the droplet were studied, as well as the influences of the droplets diameter and the overlap on the formation of the liquid lines. The minimal width, the thickness and the resistance of the prepared microelectrode were 45 μm, 2.2 μm and 5.2 μΩ cm, respectively. The minimal width of the microelectrode was 35 μm and the surface was smooth. The electrochemical flow detection of glucose concentration was carried out with the device, and the results showed that the glucose concentration had a high linear correlation with the response current, which could be used in the quantitative detection of glucose concentration. The fabrication of the electrochemical microfluidic device based on the pulse driving and controlling of micro fluids technology has many advantages such as simple system structure, lower cost and higher accuracy of the micro droplet and can be used in the preparation of the devices in the biochemical analysis and biosensor areas.
2017, 45(6): 931-935
doi: 10.11895/j.issn.0253-3820.170183
Abstract:
A micro droplet generator based on V-shape linear ultrasonic motor was prepared to produce micro droplets with higher accuracy in the field of biochemistry. The device was composed of a micro droplet generator which was driven by the V-shaped linear ultrasonic motor, a three-dimensional displacement platform based on V-shaped linear ultrasonic motor, and a micro droplet separation unit based on the piezoelectric vibrator. The generating part consisted of an ultrasonic motor, a medical syringe, a silica flexible tube and a self-made micro nozzle based on glass. Utilizing the drive controller to drive the linear ultrasonic motor, the slipway pushes forward the syringe and the micro droplet was attached to the glass nozzle. The natural mode of the rod nozzle was excited by the piezoelectric vibrator. The attached droplet was separated from the tip of the nozzle after overcoming the viscous force. The separated droplet fell in a certain range. And the radius of the spherical droplet was calculated. In the experiment, distilled water was used as the initial liquid to investigate the characteristics of the micro droplets produced by the device. The experimental results showed that the droplet was attached to the tip of the micro nozzle which was formed by distilled water under the linear motor. By the vibration of the separation unit, the attached droplets formed the spherical droplets by overcoming the viscous forces in the tip of the nozzle. The radius of spherical droplets generated by this device was less than 40 μm by measuring the size.
A micro droplet generator based on V-shape linear ultrasonic motor was prepared to produce micro droplets with higher accuracy in the field of biochemistry. The device was composed of a micro droplet generator which was driven by the V-shaped linear ultrasonic motor, a three-dimensional displacement platform based on V-shaped linear ultrasonic motor, and a micro droplet separation unit based on the piezoelectric vibrator. The generating part consisted of an ultrasonic motor, a medical syringe, a silica flexible tube and a self-made micro nozzle based on glass. Utilizing the drive controller to drive the linear ultrasonic motor, the slipway pushes forward the syringe and the micro droplet was attached to the glass nozzle. The natural mode of the rod nozzle was excited by the piezoelectric vibrator. The attached droplet was separated from the tip of the nozzle after overcoming the viscous force. The separated droplet fell in a certain range. And the radius of the spherical droplet was calculated. In the experiment, distilled water was used as the initial liquid to investigate the characteristics of the micro droplets produced by the device. The experimental results showed that the droplet was attached to the tip of the micro nozzle which was formed by distilled water under the linear motor. By the vibration of the separation unit, the attached droplets formed the spherical droplets by overcoming the viscous forces in the tip of the nozzle. The radius of spherical droplets generated by this device was less than 40 μm by measuring the size.
