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2018 Volume 46 Issue 5
2018, 46(5): 631-641
doi: 10.11895/j.issn.0253-3820.171521
Abstract:
Microchip electrophoresis is emerging as a highly promising method for portability and fast analysis with minimum amount of analytes. This paper reviewed the recent development of microchip electrophoresis, and discussed the structures, materials, processing technologies, surface modification, experimental methods, and application on ion detection. The existing issues and prospects of future study were also discussed.
Microchip electrophoresis is emerging as a highly promising method for portability and fast analysis with minimum amount of analytes. This paper reviewed the recent development of microchip electrophoresis, and discussed the structures, materials, processing technologies, surface modification, experimental methods, and application on ion detection. The existing issues and prospects of future study were also discussed.
2018, 46(5): 642-649
doi: 10.11895/j.issn.0253-3820.171459
Abstract:
An electric driven cryo-trap enrichment apparatus for the movable mass spectrometer was designed to realize rapid and automatic detection of trace volatile organic compounds (VOCs) in the atmosphere. Compared with traditional cryo-trap with refrigerant, the lowest temperature of cryocooler was down to -196℃, and it was easy to carry due to its small size, light weight and refrigerant-free. Cryo-trap combined with time-of-flight mass spectrometer was used to analyze benzene, toluene and xylene, and the result showed that the signal strength of benzene, toluene and xylene, with the cryo-trap enrichment, was improved by 212-fold, 254-fold and 242-fold, and the recoveries reached 98%, 87% and 87%, respectively. The analytical time for single sample was only 14 min. The electric driven cryo-trap combined with on-line mass spectrometer was used to detect 39 kinds of VOCs listed in TO-14 method of EPA and ambient air, and the sensitivity of the newly designed instrument was better than the threshold of national indoor VOCs. The combination of electric driven cryo-trap and time-of-flight mass spectrometer could be used for rapid enrichment and monitoring of trace VOCs in the atmosphere and indoor air, showing great potential in in-site measurement and real-time monitoring of volatile organic pollutants.
An electric driven cryo-trap enrichment apparatus for the movable mass spectrometer was designed to realize rapid and automatic detection of trace volatile organic compounds (VOCs) in the atmosphere. Compared with traditional cryo-trap with refrigerant, the lowest temperature of cryocooler was down to -196℃, and it was easy to carry due to its small size, light weight and refrigerant-free. Cryo-trap combined with time-of-flight mass spectrometer was used to analyze benzene, toluene and xylene, and the result showed that the signal strength of benzene, toluene and xylene, with the cryo-trap enrichment, was improved by 212-fold, 254-fold and 242-fold, and the recoveries reached 98%, 87% and 87%, respectively. The analytical time for single sample was only 14 min. The electric driven cryo-trap combined with on-line mass spectrometer was used to detect 39 kinds of VOCs listed in TO-14 method of EPA and ambient air, and the sensitivity of the newly designed instrument was better than the threshold of national indoor VOCs. The combination of electric driven cryo-trap and time-of-flight mass spectrometer could be used for rapid enrichment and monitoring of trace VOCs in the atmosphere and indoor air, showing great potential in in-site measurement and real-time monitoring of volatile organic pollutants.
2018, 46(5): 650-657,734
doi: 10.11895/j.issn.0253-3820.171398
Abstract:
A two-dimensional liquid chromatography method was developed for the analysis of rice leaves proteomics based on the coupling of hydrophilic interaction liquid chromatography-reversed-phase liquid chromatography with online tandem mass spectrometry. The influence of pH value of chromatographic mobile phase on the orthogonality of the hydrophilic interaction-reversed-phase two-dimensional liquid chromatography was evaluated by the changes of standard peptide retention. The results indicated that the better orthogonality (R2=0.34113) was achieved from the system with hydrophilic interaction columns (pH 9.3) in the first and C18 columns (pH 3.3) in the second LC dimension. Coupled with multiple fraction concatenation strategy, the orthogonality of two-dimensional liquid chromatography was further evaluated in the analysis of complex rice leaf proteins. The results showed that more than 50% of the total peptides were identified less than two times, and the peptides obtained from first-dimension were well distributed across the elution window, indicating that the method showed significant orthogonality in the identification of complex rice leaf proteins. Based on the proteome discoverer software, 207345 peptides belonged to 2930 protein clusters were identified.
A two-dimensional liquid chromatography method was developed for the analysis of rice leaves proteomics based on the coupling of hydrophilic interaction liquid chromatography-reversed-phase liquid chromatography with online tandem mass spectrometry. The influence of pH value of chromatographic mobile phase on the orthogonality of the hydrophilic interaction-reversed-phase two-dimensional liquid chromatography was evaluated by the changes of standard peptide retention. The results indicated that the better orthogonality (R2=0.34113) was achieved from the system with hydrophilic interaction columns (pH 9.3) in the first and C18 columns (pH 3.3) in the second LC dimension. Coupled with multiple fraction concatenation strategy, the orthogonality of two-dimensional liquid chromatography was further evaluated in the analysis of complex rice leaf proteins. The results showed that more than 50% of the total peptides were identified less than two times, and the peptides obtained from first-dimension were well distributed across the elution window, indicating that the method showed significant orthogonality in the identification of complex rice leaf proteins. Based on the proteome discoverer software, 207345 peptides belonged to 2930 protein clusters were identified.
2018, 46(5): 658-663
doi: 10.11895/j.issn.0253-3820.171151
Abstract:
A new sensitive method for detection of cumulative radon radiation based on the lead was established. PS2.M which stabilized by K+ with hemin as a co-factor exhibits superior peroxidase-like activity, and can effectively catalyze the H2O2-mediated oxidation of TMB. In the presence of Pb2+, K+-stabilized PS2.M DNAzymes are induced to undergo a conformational change, because Pb2+ has a higher efficiency with regard to stabilizing G-quadruplexes than K+, accompanied by a decrease of catalytic activity and a sharp decrease of readout signal. In the work, a novel "turn-off" model of colorimetry-Pb2+ biosensor based on superior peroxidase-like activity of G-quadruplex for Pb2+ analysis was developed. The fading degree of reaction system (ΔA value) was linearly related to Pb2+ concentration in the range of 5.0×10-9-1.8×10-7 mol/L. The linear regression equation was ΔA=0.36+0.13C (10-8 mol/L), with R=0.9987. The detection limits of lead and radon were 3.76 nmol/L(S/N=3) and 1.96×103 Bq·h/m3(S/N=3), respectively. The method exhibited good selectivity, high sensitivity and convenient operation, and could avoid the radioactive hazard in determination of the radon in environment.
A new sensitive method for detection of cumulative radon radiation based on the lead was established. PS2.M which stabilized by K+ with hemin as a co-factor exhibits superior peroxidase-like activity, and can effectively catalyze the H2O2-mediated oxidation of TMB. In the presence of Pb2+, K+-stabilized PS2.M DNAzymes are induced to undergo a conformational change, because Pb2+ has a higher efficiency with regard to stabilizing G-quadruplexes than K+, accompanied by a decrease of catalytic activity and a sharp decrease of readout signal. In the work, a novel "turn-off" model of colorimetry-Pb2+ biosensor based on superior peroxidase-like activity of G-quadruplex for Pb2+ analysis was developed. The fading degree of reaction system (ΔA value) was linearly related to Pb2+ concentration in the range of 5.0×10-9-1.8×10-7 mol/L. The linear regression equation was ΔA=0.36+0.13C (10-8 mol/L), with R=0.9987. The detection limits of lead and radon were 3.76 nmol/L(S/N=3) and 1.96×103 Bq·h/m3(S/N=3), respectively. The method exhibited good selectivity, high sensitivity and convenient operation, and could avoid the radioactive hazard in determination of the radon in environment.
2018, 46(5): 664-669
doi: 10.11895/j.issn.0253-3820.171384
Abstract:
Dehydrins are well associated with the abiotic stress tolerance of the plants, such as dehydration, salt stress and cold stress. They include a highly conserved lysine-rich motif called K-segment, which is believed to play a significant role in dehydrin function. The K-segment shows in vitro antibacterial activity against Gram-positive bacteria like its full-length dehydrin protein. In this study, the structures of the K-segment from rice dehydrin have been investigated by CD spectroscopy, NMR and molecular dynamic simulation. The results reveal that the K-segment is disordered in aqueous solution, but adopts helical structure in mimetic membrane environment, sodium dodecyl sulfate (SDS) micelles. The central region of K-segment forms an a-helix and exhibits amphipathic arrangement, where hydrophobic residues locate on one side and hydrophilic residues are on the other side. The amphipathic feature allows the helix region of the K-segment to insert into the SDS micelles, resulting in stable association with mimetic membrane. To realize the energy minimization, the hydrophobic side of the helix faces to the hydrophobic core of SDS micelles, and the hydrophilic side of the helix faces to the surface of micelles. The precise 3D structure and orientation information of the K-segment obtained in this work might provide new insights in understanding the structure-function relationship of dehydrins.
Dehydrins are well associated with the abiotic stress tolerance of the plants, such as dehydration, salt stress and cold stress. They include a highly conserved lysine-rich motif called K-segment, which is believed to play a significant role in dehydrin function. The K-segment shows in vitro antibacterial activity against Gram-positive bacteria like its full-length dehydrin protein. In this study, the structures of the K-segment from rice dehydrin have been investigated by CD spectroscopy, NMR and molecular dynamic simulation. The results reveal that the K-segment is disordered in aqueous solution, but adopts helical structure in mimetic membrane environment, sodium dodecyl sulfate (SDS) micelles. The central region of K-segment forms an a-helix and exhibits amphipathic arrangement, where hydrophobic residues locate on one side and hydrophilic residues are on the other side. The amphipathic feature allows the helix region of the K-segment to insert into the SDS micelles, resulting in stable association with mimetic membrane. To realize the energy minimization, the hydrophobic side of the helix faces to the hydrophobic core of SDS micelles, and the hydrophilic side of the helix faces to the surface of micelles. The precise 3D structure and orientation information of the K-segment obtained in this work might provide new insights in understanding the structure-function relationship of dehydrins.
2018, 46(5): 670-677
doi: 10.11895/j.issn.0253-3820.181041
Abstract:
Functional groups may change the electrical characteristics of graphene quantum dots, thus leading to the improvement of their properties and related applications. To improve the optical properties, we designed and synthesized pentaethylene hexamine and dodecylamine functionalized graphene quantum dots (PEHA-GQD-DA). Citric acid was mixed with pentaethylene hexamine and heated at 170℃ for 0.5 h. Then dodecylamine was added and the reaction was continued at 160℃ for 1.5 h to obtain PEHA-GQD-DA. The Yesults revealed that the PEHA-GQD-DA was composed of the graphene sheets from 1 nm to 3 nm, and their edges contained abundant functional groups. The introduction of pentaethylene hexamine greatly improved the fluorescence emission. The fluorescence quantum yield reached 72.7%, which was much higher than that of the GQD prepared by the thermal hydrolysis of single citric acid. The introduction of dodecylamine created a special amphiphilic structure that allows the quantum dots more likely to enter cell through the phospholipid bilayer of cell membrane. The PEHA-GQD-DA exhibited an excellent optical behavior for pH value of the medium. Within pH range of 1.0-6.5, the fluorescence intensity increased with the increase of pH value. The fluorescence spectrum sensitively changed with the change of pH value. There was a good linear relationship between the maximum emission wavelength and the pH value. When the pH was in the range of 6.5-12.0, the fluorescence spectrum didn't change with the change of pH value. However, its fluorescence intensity linearly decreased with the increase of pH value. The existence of common inorganic ions and organic small molecules does not interfere with pH response of the quantum dots. The PEHA-GQD-DA has been successfully applied to fluorescent detection of pH value in water samples and Hela cell imaging.
Functional groups may change the electrical characteristics of graphene quantum dots, thus leading to the improvement of their properties and related applications. To improve the optical properties, we designed and synthesized pentaethylene hexamine and dodecylamine functionalized graphene quantum dots (PEHA-GQD-DA). Citric acid was mixed with pentaethylene hexamine and heated at 170℃ for 0.5 h. Then dodecylamine was added and the reaction was continued at 160℃ for 1.5 h to obtain PEHA-GQD-DA. The Yesults revealed that the PEHA-GQD-DA was composed of the graphene sheets from 1 nm to 3 nm, and their edges contained abundant functional groups. The introduction of pentaethylene hexamine greatly improved the fluorescence emission. The fluorescence quantum yield reached 72.7%, which was much higher than that of the GQD prepared by the thermal hydrolysis of single citric acid. The introduction of dodecylamine created a special amphiphilic structure that allows the quantum dots more likely to enter cell through the phospholipid bilayer of cell membrane. The PEHA-GQD-DA exhibited an excellent optical behavior for pH value of the medium. Within pH range of 1.0-6.5, the fluorescence intensity increased with the increase of pH value. The fluorescence spectrum sensitively changed with the change of pH value. There was a good linear relationship between the maximum emission wavelength and the pH value. When the pH was in the range of 6.5-12.0, the fluorescence spectrum didn't change with the change of pH value. However, its fluorescence intensity linearly decreased with the increase of pH value. The existence of common inorganic ions and organic small molecules does not interfere with pH response of the quantum dots. The PEHA-GQD-DA has been successfully applied to fluorescent detection of pH value in water samples and Hela cell imaging.
2018, 46(5): 678-683
doi: 10.11895/j.issn.0253-3820.171136
Abstract:
A methodology of quantitative analysis on ginsenoside Re (G-Re) in rat plasma by ultra performance liquid chromatography-triple quadrupole mass spectrometry was developed for comparing the pharmacokinetic profiles between normal rats and Ultraviolet B (UVB) irradiation-induced damage rats after oral administration. The sample separation was carried out on an Ascentis® Express C18 column (5.0 mm×3.0 mm, 2.7 μm) with 0.1% formic acid in water and acetonitrile as the mobile phase under gradient elution. MS analysis was operated in multiple-reaction monitoring (MRM) mode using electrospray ionization (ESI) with negative ion mode, and the ions for quantification were m/z 991.54/945.53/475.60. The limit of detection (LOD, S/N=3), limit of quantification (LOQ, S/N=10) were 4.0 ng/mL and 13.5 ng/mL, respectively. G-Re was in good linearity between 15 ng/mL and 20000 ng/mL (r=0.999), the intra-day and inter-day precisions, recovery, matrix effect and stability could meet the pharmacokinetic analysis requirement. The results indicated that the metabolic process of G-Re conformed to a two-compartment pharmacokinetic model after single oral administration in the normal and model groups. The t1/2α were (0.21±0.04) h and (0.69±0.07) h, respectively; t1/2β were (17.08±0.53) and (21.40 ±16.77) h, respectively; AUC (0-t) were (321.91±2.27) μg/(L·h) and (474.99±194.96) μg/(L·h), respectively; AUC(0-∞) were (332.44±1.66) μg/(L·h) and (518.64±231.39) μg/(L·h), respectively; the pharmacokinetic parameters were significantly different between normal and UVB irradiated rats (p<0.05), except for t1/2α. This UHPLC-QQQ-MS method showed excellent separation, accuracy, high sensitivity, specificity and good repeatability, and it was suitable for the pharmacokinetic study of G-Re in vivo.
A methodology of quantitative analysis on ginsenoside Re (G-Re) in rat plasma by ultra performance liquid chromatography-triple quadrupole mass spectrometry was developed for comparing the pharmacokinetic profiles between normal rats and Ultraviolet B (UVB) irradiation-induced damage rats after oral administration. The sample separation was carried out on an Ascentis® Express C18 column (5.0 mm×3.0 mm, 2.7 μm) with 0.1% formic acid in water and acetonitrile as the mobile phase under gradient elution. MS analysis was operated in multiple-reaction monitoring (MRM) mode using electrospray ionization (ESI) with negative ion mode, and the ions for quantification were m/z 991.54/945.53/475.60. The limit of detection (LOD, S/N=3), limit of quantification (LOQ, S/N=10) were 4.0 ng/mL and 13.5 ng/mL, respectively. G-Re was in good linearity between 15 ng/mL and 20000 ng/mL (r=0.999), the intra-day and inter-day precisions, recovery, matrix effect and stability could meet the pharmacokinetic analysis requirement. The results indicated that the metabolic process of G-Re conformed to a two-compartment pharmacokinetic model after single oral administration in the normal and model groups. The t1/2α were (0.21±0.04) h and (0.69±0.07) h, respectively; t1/2β were (17.08±0.53) and (21.40 ±16.77) h, respectively; AUC (0-t) were (321.91±2.27) μg/(L·h) and (474.99±194.96) μg/(L·h), respectively; AUC(0-∞) were (332.44±1.66) μg/(L·h) and (518.64±231.39) μg/(L·h), respectively; the pharmacokinetic parameters were significantly different between normal and UVB irradiated rats (p<0.05), except for t1/2α. This UHPLC-QQQ-MS method showed excellent separation, accuracy, high sensitivity, specificity and good repeatability, and it was suitable for the pharmacokinetic study of G-Re in vivo.
2018, 46(5): 684-689
doi: 10.11895/j.issn.0253-3820.171239
Abstract:
The structure of fibrauretin made by our lab was modified. Fibrauretin was demethylated at 9-site under high temperature pyrolysis at 160℃-180℃ and was reacted with a series of acid chlorides. Twele derivatives of fibrauretin were obtained. The structure of each derivative was determined by1H-NMR and13C-NMR. The derivatives were 9-O-benzoyl-fibrauretin, 9-O-(2-methylbenzoyl)-fibrauretin, 9-O-(4-methylbenzoyl)-fibrauretin, 9-O-(3,5-dimethylbenzoyl)-fibrauretin, 9-O-(4-(chloromethyl)benzoyl)-fibrauretin and other derivatives. The 12 derivatives are all new chemical compounds. Taking ATCI as substrate, the inhibitory activity on acetylcholinesterase (AChE) from the head of flies of the fibrauretin and its derivatives were screened. The results showed that most of the derivatives had improved their inhibitory activity on AChE through esterification reaction. Compounds 9-O-(4-methylbenzoyl)-fibrauretin, 9-O-(3,5-dimethylbenzoyl)-fibrauretinand 9-O-(4-(chloromethyl)benzoyl)-fibrauretin had significant inhibitory effect on AChE, and the inhibitory activity was stronger than the that of donepezil.
The structure of fibrauretin made by our lab was modified. Fibrauretin was demethylated at 9-site under high temperature pyrolysis at 160℃-180℃ and was reacted with a series of acid chlorides. Twele derivatives of fibrauretin were obtained. The structure of each derivative was determined by1H-NMR and13C-NMR. The derivatives were 9-O-benzoyl-fibrauretin, 9-O-(2-methylbenzoyl)-fibrauretin, 9-O-(4-methylbenzoyl)-fibrauretin, 9-O-(3,5-dimethylbenzoyl)-fibrauretin, 9-O-(4-(chloromethyl)benzoyl)-fibrauretin and other derivatives. The 12 derivatives are all new chemical compounds. Taking ATCI as substrate, the inhibitory activity on acetylcholinesterase (AChE) from the head of flies of the fibrauretin and its derivatives were screened. The results showed that most of the derivatives had improved their inhibitory activity on AChE through esterification reaction. Compounds 9-O-(4-methylbenzoyl)-fibrauretin, 9-O-(3,5-dimethylbenzoyl)-fibrauretinand 9-O-(4-(chloromethyl)benzoyl)-fibrauretin had significant inhibitory effect on AChE, and the inhibitory activity was stronger than the that of donepezil.
2018, 46(5): 690-697
doi: 10.11895/j.issn.0253-3820.171458
Abstract:
As a new type of pollutants, microplastics (small pieces of plastic with the longest dimension less than 5 mm) are bringing wide concerns by policy makers and researchers. The impact of microplastics on marine life is closely related to human health. Bivalves, as filter feeding creatures, can easily ingest microplastics in their feeding process. The microplastics in these bivalves can easily enter the human body through the food chain. In this study, a bivalve sample pretreatment method was established for separating the microplastics in their digestive system. Qualitative and quantitative analysis of microplastics was carried out by micro-Fourier transformed infrared spectroscope (μ-FT-IR) and Stereo microscope. By comparing the digestion systems of using 10% KOH and 30% H2O2, respectively, it was found that the digestion system using 10% KOH had better digestion efficiency. The recoveries of polypropylene (PP), polyethylene (PE), polystyrene (PS) and polyvinyl chloride (PVC) ranged from 96.7% to 98.6%, with RSD of less than 3.2%. Therefore, 10% KOH was used to digest organic tissue for separating the microplastics from the bivalves' digestive system. With this digestion system, the microplastics in Chlamys farreri from local markets and Mytilus galloprovincialis from both local markets and wild environments in Qingdao were separated and analyzed. The results showed that microplastics were found in over 80% of the individuals purchased from the market and 40% in the collected wild individuals. The average abundance of microplastics in Chlamys farreri purchased from different markets varied from 5.2 to 19.4 items/individual and 3.2-7.1 items/g, while in Mytilus galloprovincialis, the numbers varied from 1.9 to 9.6 items/individual and 2.0-12.8 items/g. Farmed mussels contained more microplastics (average 1.9 items/individual, 3.17 items/g) than wild mussels (average 0.53 items/individual, 2.0 items/g). There were various colors of microplastics. The detected microplastics came from three shapes:fibers, fragments and granules. Fibrous microplastics, being the most dominant ones, accounted for 84.11%. The average size of fibrous microplastics (0.66±0.70 mm) was larger than that of the other two shapes of microplastics. The number of microplastics decreased with increasing microplastic sizes. Microplastics of less than 500 μm coming from different markets were in the range of 26% to 84%. There was great spatial difference in the size of microplastics. The polymer composition of the microplastic was identified by μ-FT-IR. And it was found that the most common polymer component sin the samples were cellophane (CP), followed by polypropylene (PP). In the farmed mussels, PP was the most abundant component. The results showed that the abundance and types of microplastics in cultured or wild bivalves were closely related to their growing environment.
As a new type of pollutants, microplastics (small pieces of plastic with the longest dimension less than 5 mm) are bringing wide concerns by policy makers and researchers. The impact of microplastics on marine life is closely related to human health. Bivalves, as filter feeding creatures, can easily ingest microplastics in their feeding process. The microplastics in these bivalves can easily enter the human body through the food chain. In this study, a bivalve sample pretreatment method was established for separating the microplastics in their digestive system. Qualitative and quantitative analysis of microplastics was carried out by micro-Fourier transformed infrared spectroscope (μ-FT-IR) and Stereo microscope. By comparing the digestion systems of using 10% KOH and 30% H2O2, respectively, it was found that the digestion system using 10% KOH had better digestion efficiency. The recoveries of polypropylene (PP), polyethylene (PE), polystyrene (PS) and polyvinyl chloride (PVC) ranged from 96.7% to 98.6%, with RSD of less than 3.2%. Therefore, 10% KOH was used to digest organic tissue for separating the microplastics from the bivalves' digestive system. With this digestion system, the microplastics in Chlamys farreri from local markets and Mytilus galloprovincialis from both local markets and wild environments in Qingdao were separated and analyzed. The results showed that microplastics were found in over 80% of the individuals purchased from the market and 40% in the collected wild individuals. The average abundance of microplastics in Chlamys farreri purchased from different markets varied from 5.2 to 19.4 items/individual and 3.2-7.1 items/g, while in Mytilus galloprovincialis, the numbers varied from 1.9 to 9.6 items/individual and 2.0-12.8 items/g. Farmed mussels contained more microplastics (average 1.9 items/individual, 3.17 items/g) than wild mussels (average 0.53 items/individual, 2.0 items/g). There were various colors of microplastics. The detected microplastics came from three shapes:fibers, fragments and granules. Fibrous microplastics, being the most dominant ones, accounted for 84.11%. The average size of fibrous microplastics (0.66±0.70 mm) was larger than that of the other two shapes of microplastics. The number of microplastics decreased with increasing microplastic sizes. Microplastics of less than 500 μm coming from different markets were in the range of 26% to 84%. There was great spatial difference in the size of microplastics. The polymer composition of the microplastic was identified by μ-FT-IR. And it was found that the most common polymer component sin the samples were cellophane (CP), followed by polypropylene (PP). In the farmed mussels, PP was the most abundant component. The results showed that the abundance and types of microplastics in cultured or wild bivalves were closely related to their growing environment.
2018, 46(5): 698-703
doi: 10.11895/j.issn.0253-3820.171375
Abstract:
A method for rapid determination of γ-hydroxybutyric acid (GHB) in beverages (water, sodas, beer) and urine was established by direct analysis real-time mass spectrometry (DART-MS). Samples were analyzed directly after dilution with mixture of methanol and water (1:1, V/V). Instrument parameter settings were optimized to obtain the sensitive and accurate determination of GHB. At the sample introduction speed of 0.5 mm/s, high intensity of[M-H]- ions for GHB were observed in the negative ion and selection ion monitoring mode by utilization of high purity helium gas at 350℃. For different samples of water, sodas, beer and urine, the limits of detection (LODs) (S/N=3) were in the range of 1-2 μg/mL, while the limits of quantification (LOQs) (S/N=10) were in the range of 3-5 μg/mL. The linear correlation coefficients of the standard curves with different sample matrixes were between 0.9899 and 0.9980. The recoveries were in the range of 80.8%-115.2% with the relative standard deviations of 1.9%-12.8%. With its rapid analysis and simple pretreatment steps, the method is expected to have a strong advantage in the rapid screening analysis of large quantities of beverage and urine.
A method for rapid determination of γ-hydroxybutyric acid (GHB) in beverages (water, sodas, beer) and urine was established by direct analysis real-time mass spectrometry (DART-MS). Samples were analyzed directly after dilution with mixture of methanol and water (1:1, V/V). Instrument parameter settings were optimized to obtain the sensitive and accurate determination of GHB. At the sample introduction speed of 0.5 mm/s, high intensity of[M-H]- ions for GHB were observed in the negative ion and selection ion monitoring mode by utilization of high purity helium gas at 350℃. For different samples of water, sodas, beer and urine, the limits of detection (LODs) (S/N=3) were in the range of 1-2 μg/mL, while the limits of quantification (LOQs) (S/N=10) were in the range of 3-5 μg/mL. The linear correlation coefficients of the standard curves with different sample matrixes were between 0.9899 and 0.9980. The recoveries were in the range of 80.8%-115.2% with the relative standard deviations of 1.9%-12.8%. With its rapid analysis and simple pretreatment steps, the method is expected to have a strong advantage in the rapid screening analysis of large quantities of beverage and urine.
2018, 46(5): 704-709
doi: 10.11895/j.issn.0253-3820.171249
Abstract:
An effective method was developed for determination of pyraclostrobin and BF 500-3 residues in pollen and honey of litchi by QuEChERS coupled with ultra performance liquid chromatography-tandem mass spectrometry. The samples were extracted by acetonitrile and cleaned by primary secondary amine (PSA) and C18. In the positive ion mode and multi reaction monitoring mode, the analytes were quantified by the matrix matching standard solutions, and the pretreatment and mass spectrometry conditions were evaluated. The matrix matched standard solutions of pyraclostrobin and its metabolite BF 500-3 showed good linearities in the concentration range of 1-100 μg/L, with the correlation coefficients (R2) of 0.991-0.999. The average recoveries were 87.0%-97.8% with relative standard deviations of 1.3%-3.7%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.08-0.20 μg/kg and 0.20-0.50 μg/kg, respectively. The method was easy, quick and highly sensitive, and was suitable for quick determination of pyraclotrobin and its metabolites in pollen and honey of litchi.
An effective method was developed for determination of pyraclostrobin and BF 500-3 residues in pollen and honey of litchi by QuEChERS coupled with ultra performance liquid chromatography-tandem mass spectrometry. The samples were extracted by acetonitrile and cleaned by primary secondary amine (PSA) and C18. In the positive ion mode and multi reaction monitoring mode, the analytes were quantified by the matrix matching standard solutions, and the pretreatment and mass spectrometry conditions were evaluated. The matrix matched standard solutions of pyraclostrobin and its metabolite BF 500-3 showed good linearities in the concentration range of 1-100 μg/L, with the correlation coefficients (R2) of 0.991-0.999. The average recoveries were 87.0%-97.8% with relative standard deviations of 1.3%-3.7%. The limit of detection (LOD) and the limit of quantification (LOQ) were 0.08-0.20 μg/kg and 0.20-0.50 μg/kg, respectively. The method was easy, quick and highly sensitive, and was suitable for quick determination of pyraclotrobin and its metabolites in pollen and honey of litchi.
2018, 46(5): 710-715
doi: 10.11895/j.issn.0253-3820.171064
Abstract:
A simple and sensitive method for simultaneous determination of 12 kinds of residual solvents in a new drug CBT108 was established and validated by headspace gas chromatographic technology. The rationality, accuracy and feasibility of the analytical method were verified. Under the optimized conditions, simultaneous separation and determination of 12 kinds of residual solvents, including methanol, ethanol, ether, acetone, acetonitrile, dichloromethane, n-hexane, ethyl acetate, tetrahydrofuran, heptane, toluene and carbon tetrachloride was carried out by using a DB624 capillary column (30 m × 0.53 mm × 3.0 μm) for separation, a flame ionization detector for detection and internal standard method for quantitation. Good linearity was obtained for 12 solvents with the correlation coefficients (R2) of more than 0.997. The limits of quantitation and detection were defined at S/N=3 and S/N=10, respectively. LOQ and LOD for 12 solvents were given as 0.024 μg/mL and 0.0072 μg/mL for methanol, 0.1 μg/mL and 0.012 μg/mL for ethanol, 0.01 μg/mL and 0.005 μg/mL for ether, 0.1 μg/mL and 0.008 μg/mL for acetone, 1.025 μg/mL and 0.0615 μg/mL for acetonitrile, 0.09 μg/mL and 0.06 μg/mL for dichloromethane, 0.09 μg/mL and 0.06 μg/mL for n-hexane, 0.25 μg/mL and 0.008 μg/mL for ethyl acetate, 0.108 μg/mL and 0.014 μg/mL for tetrahydrofuran, 0.16 μg/mL and 0.0004 μg/mL for carbon tetrachloride, 0.0075 μg/mL and 0.005 μg/mL for heptane, and 0.0445 μg/mL and 0.0014 μg/mL for toluene. The adding standards recoveries for 12 residual solvents at three spiked levels were in the range of 90.96%-108.67%, with relative standard deviations of 0.1%-5.7%. This simple, high accuracy and good repeatability method is feasible for rapidly determination of 12 residual solvents in drug candidate CBT108. Meanwhile, this simple method provides a consulted value for detection of residual solvents in other medicines.
A simple and sensitive method for simultaneous determination of 12 kinds of residual solvents in a new drug CBT108 was established and validated by headspace gas chromatographic technology. The rationality, accuracy and feasibility of the analytical method were verified. Under the optimized conditions, simultaneous separation and determination of 12 kinds of residual solvents, including methanol, ethanol, ether, acetone, acetonitrile, dichloromethane, n-hexane, ethyl acetate, tetrahydrofuran, heptane, toluene and carbon tetrachloride was carried out by using a DB624 capillary column (30 m × 0.53 mm × 3.0 μm) for separation, a flame ionization detector for detection and internal standard method for quantitation. Good linearity was obtained for 12 solvents with the correlation coefficients (R2) of more than 0.997. The limits of quantitation and detection were defined at S/N=3 and S/N=10, respectively. LOQ and LOD for 12 solvents were given as 0.024 μg/mL and 0.0072 μg/mL for methanol, 0.1 μg/mL and 0.012 μg/mL for ethanol, 0.01 μg/mL and 0.005 μg/mL for ether, 0.1 μg/mL and 0.008 μg/mL for acetone, 1.025 μg/mL and 0.0615 μg/mL for acetonitrile, 0.09 μg/mL and 0.06 μg/mL for dichloromethane, 0.09 μg/mL and 0.06 μg/mL for n-hexane, 0.25 μg/mL and 0.008 μg/mL for ethyl acetate, 0.108 μg/mL and 0.014 μg/mL for tetrahydrofuran, 0.16 μg/mL and 0.0004 μg/mL for carbon tetrachloride, 0.0075 μg/mL and 0.005 μg/mL for heptane, and 0.0445 μg/mL and 0.0014 μg/mL for toluene. The adding standards recoveries for 12 residual solvents at three spiked levels were in the range of 90.96%-108.67%, with relative standard deviations of 0.1%-5.7%. This simple, high accuracy and good repeatability method is feasible for rapidly determination of 12 residual solvents in drug candidate CBT108. Meanwhile, this simple method provides a consulted value for detection of residual solvents in other medicines.
2018, 46(5): 716-722
doi: 10.11895/j.issn.0253-3820.171365
Abstract:
Protopanaxadiol (PPD) has inhibitory effects on many tumors and receives much attention. However, it has poor water solubility and low utilization, which limits its clinical application. Considering these issues, in this study, we used hollow gold nanoparticles as transport carriers of PPD and synthesized PPD hollow gold nanoparticles (HAuNs). We conducted a number of experiments to investigate the in vitro anti-laryngeal cancer Hep-2 effect of a PPD HAuNs carrier. High performance liquid chromatography (HPLC) was used to detect the sustained release effect of PPD HAuNs. MTT assay was used to detect the inhibitory effect of PPD HAuNs on the proliferation of Hep-2 cells. Effect of PPD HAuNs on Hep-2 cell apoptosis was investigated by flow cytometry. The results of in vitro release showed that PPD HAuNs had sustained release effect. Compared with blank control group, HAuNs group and PPD group, the survival rate of Hep-2 cells in HAuNs-PEG-PPD group decreased more significantly and the apoptosis rate increased more significantly (p<0.01). PPD HAuNs could significantly enhance anti-laryngeal cancer effect of PPD in vitro and promote the apoptosis of tumor cells. It promotes tumor cell apoptosis, and is expected to be a new PPD drug delivery system, further promoting the application of PPD in clinical anti-laryngeal cancer.
Protopanaxadiol (PPD) has inhibitory effects on many tumors and receives much attention. However, it has poor water solubility and low utilization, which limits its clinical application. Considering these issues, in this study, we used hollow gold nanoparticles as transport carriers of PPD and synthesized PPD hollow gold nanoparticles (HAuNs). We conducted a number of experiments to investigate the in vitro anti-laryngeal cancer Hep-2 effect of a PPD HAuNs carrier. High performance liquid chromatography (HPLC) was used to detect the sustained release effect of PPD HAuNs. MTT assay was used to detect the inhibitory effect of PPD HAuNs on the proliferation of Hep-2 cells. Effect of PPD HAuNs on Hep-2 cell apoptosis was investigated by flow cytometry. The results of in vitro release showed that PPD HAuNs had sustained release effect. Compared with blank control group, HAuNs group and PPD group, the survival rate of Hep-2 cells in HAuNs-PEG-PPD group decreased more significantly and the apoptosis rate increased more significantly (p<0.01). PPD HAuNs could significantly enhance anti-laryngeal cancer effect of PPD in vitro and promote the apoptosis of tumor cells. It promotes tumor cell apoptosis, and is expected to be a new PPD drug delivery system, further promoting the application of PPD in clinical anti-laryngeal cancer.
2018, 46(5): 723-728
doi: 10.11895/j.issn.0253-3820.171253
Abstract:
As one of the most important laboratory tools for the research of quantum chemistry and astrochemistry, a microwave spectrometer can make accurate measurement of molecular spectra arising from rotational transitions. Fourier transform microwave (FTMW) spectrometers, in many cases, require down-conversion mixing plans by using mixers to bring the molecular signal down for A/D sampling, and multiple signal averaging to improve the signal/noise ratio as well. Two detection schemes, homodyne and heterodyne detection modes, were proposed in this project along with two data processing plans, averaging in the time domain and averaging in the frequency domain, to develop efficient, sensitive and accurate detection solutions for molecular rotational spectroscopy. With 0.5% OCS gas in argon as standard sample, verification experiment was conducted with frequency difference between LO and cavity resonance at 200 MHz and 0.4 MHz. The experimental results indicate that, the heterodyne detection method can provide better sensitivity than the homodyne scheme, but with increased cost for more devices, while the time-domain averaging can obtain much better signal-to-noise ratio than frequency-domain averaging, but with stronger data processing capacity and more time required.
As one of the most important laboratory tools for the research of quantum chemistry and astrochemistry, a microwave spectrometer can make accurate measurement of molecular spectra arising from rotational transitions. Fourier transform microwave (FTMW) spectrometers, in many cases, require down-conversion mixing plans by using mixers to bring the molecular signal down for A/D sampling, and multiple signal averaging to improve the signal/noise ratio as well. Two detection schemes, homodyne and heterodyne detection modes, were proposed in this project along with two data processing plans, averaging in the time domain and averaging in the frequency domain, to develop efficient, sensitive and accurate detection solutions for molecular rotational spectroscopy. With 0.5% OCS gas in argon as standard sample, verification experiment was conducted with frequency difference between LO and cavity resonance at 200 MHz and 0.4 MHz. The experimental results indicate that, the heterodyne detection method can provide better sensitivity than the homodyne scheme, but with increased cost for more devices, while the time-domain averaging can obtain much better signal-to-noise ratio than frequency-domain averaging, but with stronger data processing capacity and more time required.
2018, 46(5): 729-734
doi: 10.11895/j.issn.0253-3820.171246
Abstract:
A printed polymer for selective identification of levofloxacin was synthesized on the surface of silica gel with levofloxacin as template molecule. The polymer was characterized by elemental analysis and infrared spectroscopy, and the properties of the polymer were determined by dynamic adsorption and selective adsorption. The results showed that the maximum adsorption capacity of the imprinted polymer was 56.33 mg/g and the imprinting factor was 2.62. The imprinted polymer was applied to quantitative analysis of levofloxacin with molecular imprinted solid phase extraction spectroscopy (SPES). The SPES was carried out in an elaborately designed device with which the interested analyte was extracted by the solid phase extraction medium and the diffuse reflectance spectrum was measured directly on the solid medium without elution. SPES has simplified the operation process and improved the sensitivity. The regression equation of the standard curve was A=0.0496C+0.2412, the correlation coefficient (R2) was 0.9924, the linear range was 0.25-9.0 mg/L, and the detection limit was 0.24 mg/L. The recoveries of determination of levofloxacin in Pork samples were 89.1%-92.0%, and the relative standard deviations (RSDs) of the three parallel tests were 3.4%-7.9%. Compared with the traditional enrichment and separation technique, this method developed here had some advantages such as miniaturization and integration, high sensitivity and selectivity, low cost, simple operation and rapid detection.
A printed polymer for selective identification of levofloxacin was synthesized on the surface of silica gel with levofloxacin as template molecule. The polymer was characterized by elemental analysis and infrared spectroscopy, and the properties of the polymer were determined by dynamic adsorption and selective adsorption. The results showed that the maximum adsorption capacity of the imprinted polymer was 56.33 mg/g and the imprinting factor was 2.62. The imprinted polymer was applied to quantitative analysis of levofloxacin with molecular imprinted solid phase extraction spectroscopy (SPES). The SPES was carried out in an elaborately designed device with which the interested analyte was extracted by the solid phase extraction medium and the diffuse reflectance spectrum was measured directly on the solid medium without elution. SPES has simplified the operation process and improved the sensitivity. The regression equation of the standard curve was A=0.0496C+0.2412, the correlation coefficient (R2) was 0.9924, the linear range was 0.25-9.0 mg/L, and the detection limit was 0.24 mg/L. The recoveries of determination of levofloxacin in Pork samples were 89.1%-92.0%, and the relative standard deviations (RSDs) of the three parallel tests were 3.4%-7.9%. Compared with the traditional enrichment and separation technique, this method developed here had some advantages such as miniaturization and integration, high sensitivity and selectivity, low cost, simple operation and rapid detection.
2018, 46(5): 735-742
doi: 10.11895/j.issn.0253-3820.171489
Abstract:
Due to the diversity and complexity, the change of chemical components in medicinal plant according to the time, cultivated varieties or ecological condition is difficult to recognize using traditional phytochemistry method. In order to analyze the pharmacodynamics material basis in Uighur medicinal plant Artemisia rupestris L. in an effective and comprehensive way, a plant metabolomics approach was established based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). This study firstly focused on the effect of extraction solvents, redissolve solvents and ultrasonic time on the untargeted metabolomics, then the optimal preparation condition was selected according to metabolites coverage. After methodology validation, the approach was applied to acquire metabolic information in root, stem, branchlet, leaf and flower of Artemisia rupestris L. The results showed that the metabolome in flower was obviously different with the other organs. Coupling with multivariate statistical analysis, a batch of differential metabolites were picked out, in which 61 flavonoids, 97 rupestonic acid derivatives, 7 chlorogenic acids and 15 other compounds were primarily recognized according to the characteristic fragmentation rules of specific structure type and database retrieval. Additionally, the distribution characteristics of the above 180 differential metabolites was illustrated by cluster heat map. In conclusion, this study provided important information about the rational utilization of effective parts from Artemisia rupestris L., and offered a novel strategy for quality control, variety improvement and reasonable development of medicinal plants.
Due to the diversity and complexity, the change of chemical components in medicinal plant according to the time, cultivated varieties or ecological condition is difficult to recognize using traditional phytochemistry method. In order to analyze the pharmacodynamics material basis in Uighur medicinal plant Artemisia rupestris L. in an effective and comprehensive way, a plant metabolomics approach was established based on liquid chromatography-tandem mass spectrometry (LC-MS/MS). This study firstly focused on the effect of extraction solvents, redissolve solvents and ultrasonic time on the untargeted metabolomics, then the optimal preparation condition was selected according to metabolites coverage. After methodology validation, the approach was applied to acquire metabolic information in root, stem, branchlet, leaf and flower of Artemisia rupestris L. The results showed that the metabolome in flower was obviously different with the other organs. Coupling with multivariate statistical analysis, a batch of differential metabolites were picked out, in which 61 flavonoids, 97 rupestonic acid derivatives, 7 chlorogenic acids and 15 other compounds were primarily recognized according to the characteristic fragmentation rules of specific structure type and database retrieval. Additionally, the distribution characteristics of the above 180 differential metabolites was illustrated by cluster heat map. In conclusion, this study provided important information about the rational utilization of effective parts from Artemisia rupestris L., and offered a novel strategy for quality control, variety improvement and reasonable development of medicinal plants.
2018, 46(5): 743-749
doi: 10.11895/j.issn.0253-3820.181091
Abstract:
Food-borne pathogenic bacteria seriously threaten public health. Based on the mechanism of fluorescence resonance energy transfer (FRET), a ratiometric fluorescence biosensor was constructed by integration of Exo III-based signal amplification strategy. The Cy3 labeled R1-DNA firstly hybridized with Cy5 labeled R2-DNA to form duplex of R1/R2. Cy3 showed a low fluorescence response while Cy5 showed a high fluorescence response. The addition of target pathogenic bacterial gene (Lac Z gene) could de-hybridize the R1/R2, resulting in the fluorescence decreasing of Cy5 and the fluorescence recovering of Cy3. Under the assistance of Exo III, the signal change was further amplified. The detection of limit reached as low as 5.29 pmol/L. The linear detection range was from 10 pmol/L to 2000 pmol/L. The developed ratiomtric detection strategy significantly reduced the possibility of false-positive and false-negative detection results.
Food-borne pathogenic bacteria seriously threaten public health. Based on the mechanism of fluorescence resonance energy transfer (FRET), a ratiometric fluorescence biosensor was constructed by integration of Exo III-based signal amplification strategy. The Cy3 labeled R1-DNA firstly hybridized with Cy5 labeled R2-DNA to form duplex of R1/R2. Cy3 showed a low fluorescence response while Cy5 showed a high fluorescence response. The addition of target pathogenic bacterial gene (Lac Z gene) could de-hybridize the R1/R2, resulting in the fluorescence decreasing of Cy5 and the fluorescence recovering of Cy3. Under the assistance of Exo III, the signal change was further amplified. The detection of limit reached as low as 5.29 pmol/L. The linear detection range was from 10 pmol/L to 2000 pmol/L. The developed ratiomtric detection strategy significantly reduced the possibility of false-positive and false-negative detection results.
2018, 46(5): 750-756
doi: 10.11895/j.issn.0253-3820.170127
Abstract:
A simple, sensitive and reliable method was developed for simultaneous determination of ten banned drugs residues including zeranols (ZALs), chloroamphenicol, pentachlorophenol, etc. in swine urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The urine samples were pretreated using lyophilization and QuEChERS procedures, respectively. Acetonitrile and ammonium acetate (5 mmol/L) were chosen as mobile phases. Target compounds were separated well in ZorbaxSB-C18 by following the optimized gradient elution program and determined by LC-MS/MS in negative electrospray ionization mode. The linearity of the matrix-matched standard curve of ten analytes in two methods was good in the range of the experimental concentration with correlation coefficients more than 0.99. The recoveries of ten drugs were in the range of 80.7%-107.7% and 73.5%-103.3% at the spiked levels of 5, 10 and 20 μg/L by lyophilization and QuEChERS methods, respectively. The coefficients of variation were less than 15%. The limits of detection (LOD) and the limits of quantification (LOQ) from lyophilization and QuEChERS method were 0.1 to 2.0 μg/L and 0.2 to 5.0 μg/L, respectively.
A simple, sensitive and reliable method was developed for simultaneous determination of ten banned drugs residues including zeranols (ZALs), chloroamphenicol, pentachlorophenol, etc. in swine urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The urine samples were pretreated using lyophilization and QuEChERS procedures, respectively. Acetonitrile and ammonium acetate (5 mmol/L) were chosen as mobile phases. Target compounds were separated well in ZorbaxSB-C18 by following the optimized gradient elution program and determined by LC-MS/MS in negative electrospray ionization mode. The linearity of the matrix-matched standard curve of ten analytes in two methods was good in the range of the experimental concentration with correlation coefficients more than 0.99. The recoveries of ten drugs were in the range of 80.7%-107.7% and 73.5%-103.3% at the spiked levels of 5, 10 and 20 μg/L by lyophilization and QuEChERS methods, respectively. The coefficients of variation were less than 15%. The limits of detection (LOD) and the limits of quantification (LOQ) from lyophilization and QuEChERS method were 0.1 to 2.0 μg/L and 0.2 to 5.0 μg/L, respectively.
2018, 46(5): 757-764,786
doi: 10.11895/j.issn.0253-3820.171503
Abstract:
Pulsed glow discharge mass spectrometric (Pulsed-GDMS) method for the measurement of 7 kinds of key elements (Mg, Fe, Cu, La, Ce, Pr and Nd) in rare earth alloys was established. The influence factors of measurement repeatability, such as pulse time, sample homogeneity, anode cap, flow tube, corn, and sample tablet density were systematically studied. The results showed that, for elements with mass fraction of more than mg/g, the parts (anode cap, flow tube and corn) had the largest influence on measurement repeatability. When the new graphitic parts were used and no parts were changed during the whole measurement, the relative standard deviation (RSD) was less than 3%. However, the RSD were 2%-11% and 3%-21% when the new graphitic parts and the reusable parts were used and changed, respectively. The second influence factor of measurement repeatability was the tablet density. The results showed that, the lower the density, the worse the measurement repeatability, and for the dense tablet, the RSD was less than 3%. Key elements in 1# rare earth alloy were measured by high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS), and the analytical results were used as reference values for the calibration of Pulsed-GDMS. The relative sensitivity factors (RSF) were obtained, and the key elements in 2# rare earth alloy were measured by Pulsed-GDMS after calibration. The analytical results of key elements in 2# sample by Pulsed-GDMS and HR-ICP-MS were compared, and the results showed that for the dense sample, the analytical results showed good agreement. Under the optimal conditions, the expanded uncertainty of measurement by Pulsed-GDMS reduced to 3%-10%.
Pulsed glow discharge mass spectrometric (Pulsed-GDMS) method for the measurement of 7 kinds of key elements (Mg, Fe, Cu, La, Ce, Pr and Nd) in rare earth alloys was established. The influence factors of measurement repeatability, such as pulse time, sample homogeneity, anode cap, flow tube, corn, and sample tablet density were systematically studied. The results showed that, for elements with mass fraction of more than mg/g, the parts (anode cap, flow tube and corn) had the largest influence on measurement repeatability. When the new graphitic parts were used and no parts were changed during the whole measurement, the relative standard deviation (RSD) was less than 3%. However, the RSD were 2%-11% and 3%-21% when the new graphitic parts and the reusable parts were used and changed, respectively. The second influence factor of measurement repeatability was the tablet density. The results showed that, the lower the density, the worse the measurement repeatability, and for the dense tablet, the RSD was less than 3%. Key elements in 1# rare earth alloy were measured by high resolution inductively coupled plasma-mass spectrometry (HR-ICP-MS), and the analytical results were used as reference values for the calibration of Pulsed-GDMS. The relative sensitivity factors (RSF) were obtained, and the key elements in 2# rare earth alloy were measured by Pulsed-GDMS after calibration. The analytical results of key elements in 2# sample by Pulsed-GDMS and HR-ICP-MS were compared, and the results showed that for the dense sample, the analytical results showed good agreement. Under the optimal conditions, the expanded uncertainty of measurement by Pulsed-GDMS reduced to 3%-10%.
Electrochemical Dopamine Sensor Based on Multi-Walled Carbon Nanotubes-Tungsten Oxide Nanocomposites
2018, 46(5): 765-772,795
doi: 10.11895/j.issn.0253-3820.171431
Abstract:
Multi-walled carbon nanotubes-tungsten oxide (MWCNTs-WOx) nanocomposites were fabricated on glassy carbon electrode (GCE) through a simple electrodeposition method, in which WOx were fabricated on MWCNTs. The morphology and constitution were characterized by field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical characterization of modified electrode was done by electrochemical impedance spectroscopy (EIS). The cyclic voltammogram (CV) method was adopted to investigate the electrochemical behavior of dopamine (DA) on MWCNTs-WOx-modified glassy carbon electrode, and a new detection method for DA was developed by differential pulse voltammetry (DPV). The results showed that MWCNTs-WOx nanocomposites had obvious electrocatalytic effect on DA in phosphate buffer solution (pH=6.5). Under the optimized experimental conditions, the DA peak current demonstrated a good linear relationship with concentration in the range of 0.05-1.00 mmol/L, and the detection limit was 17 μmol/L (S/N=3). Effects of different experimental parameters on the response current of the modified electrode were investigated, and it was found that the prepared electrochemical sensor displayed good reproducibility, high selectivity and strong anti-interference ability. UA did not interfere with the detection of DA. A new electrochemical method for the quantitative determination of DA was established and successfully applied to the determination of dopamine hydrochloride injection samples.
Multi-walled carbon nanotubes-tungsten oxide (MWCNTs-WOx) nanocomposites were fabricated on glassy carbon electrode (GCE) through a simple electrodeposition method, in which WOx were fabricated on MWCNTs. The morphology and constitution were characterized by field emission scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Electrochemical characterization of modified electrode was done by electrochemical impedance spectroscopy (EIS). The cyclic voltammogram (CV) method was adopted to investigate the electrochemical behavior of dopamine (DA) on MWCNTs-WOx-modified glassy carbon electrode, and a new detection method for DA was developed by differential pulse voltammetry (DPV). The results showed that MWCNTs-WOx nanocomposites had obvious electrocatalytic effect on DA in phosphate buffer solution (pH=6.5). Under the optimized experimental conditions, the DA peak current demonstrated a good linear relationship with concentration in the range of 0.05-1.00 mmol/L, and the detection limit was 17 μmol/L (S/N=3). Effects of different experimental parameters on the response current of the modified electrode were investigated, and it was found that the prepared electrochemical sensor displayed good reproducibility, high selectivity and strong anti-interference ability. UA did not interfere with the detection of DA. A new electrochemical method for the quantitative determination of DA was established and successfully applied to the determination of dopamine hydrochloride injection samples.
2018, 46(5): 773-779
doi: 10.11895/j.issn.0253-3820.171108
Abstract:
Carbon nanosheets load beta-cyclodextrin (β-CD-CNS) as a new modified electrode materials was reported for the electrochemical determination of sulfadiazine (SD). Carbon nanosheets (CNS) were prepared by a new method of ultrasonic electrolysis in which the β-CD was attached on CNS through ultrasonic dispersion method. The β-CD-CNS composite nanomaterials were immobilized onto glassy carbon electrodes with drops of coating method to construct an SD voltammetric sensor. The differential pulse stripping voltammetry (DPSV) was used to characterize the electrocatalytic behavior of the developed sensor. The Effects of some parameters on the response behavior of the sensor such as pH, modification amount, scanning rate, stirring speed, stirring time, deposition potential and time were investigated and optimized. The results indicated that the β-CD-CNS composite nanomaterials had excellent electroactivity for the SD in neutral solution and greatly improved the current response of SD. Under the optimal conditions, the SD had an irreversible characteristic oxidation peak around +0.87 V, and the oxidation peak current ip (μA) had a good linear relationship with the concentration C (μmol/L) of the SD in concentration range of 0.05 μmol/L-13.5 μmol/L with correlation coefficients of 0.999. The detection limit was 12.2 nmol/L (S/N=3). The sensor was successfully applied for the trace SD determination in water and milk samples and the recoveries from the spiked samples were 80.0%-102% with RSD ≤ 5.2%.
Carbon nanosheets load beta-cyclodextrin (β-CD-CNS) as a new modified electrode materials was reported for the electrochemical determination of sulfadiazine (SD). Carbon nanosheets (CNS) were prepared by a new method of ultrasonic electrolysis in which the β-CD was attached on CNS through ultrasonic dispersion method. The β-CD-CNS composite nanomaterials were immobilized onto glassy carbon electrodes with drops of coating method to construct an SD voltammetric sensor. The differential pulse stripping voltammetry (DPSV) was used to characterize the electrocatalytic behavior of the developed sensor. The Effects of some parameters on the response behavior of the sensor such as pH, modification amount, scanning rate, stirring speed, stirring time, deposition potential and time were investigated and optimized. The results indicated that the β-CD-CNS composite nanomaterials had excellent electroactivity for the SD in neutral solution and greatly improved the current response of SD. Under the optimal conditions, the SD had an irreversible characteristic oxidation peak around +0.87 V, and the oxidation peak current ip (μA) had a good linear relationship with the concentration C (μmol/L) of the SD in concentration range of 0.05 μmol/L-13.5 μmol/L with correlation coefficients of 0.999. The detection limit was 12.2 nmol/L (S/N=3). The sensor was successfully applied for the trace SD determination in water and milk samples and the recoveries from the spiked samples were 80.0%-102% with RSD ≤ 5.2%.
2018, 46(5): 780-786
doi: 10.11895/j.issn.0253-3820.171276
Abstract:
The effect of CdS quantum dots (QDs) on the electrochemiluminescence (ECL) signal of Ru(bpy)32+ was studied. It was found that CdS QDs could enhance the anodic ECL of Ru(bpy)32+ by 4 times. The sensitization mechanism was discussed and the influence factors including concentrations of Ru(bpy)32+ and CdS QDs, pH of solution and scan rate on ECL intensity were investigated. On the basis of quenching effect of catechol on the ECL signal of CdS QDs-Ru(bpy)32+, a system for sensitive determination of catechol was established with a detection limit of 5.5 nmol/L (S/N=3). This method was applied to the detection of catechol in tea sample with satisfactory results.
The effect of CdS quantum dots (QDs) on the electrochemiluminescence (ECL) signal of Ru(bpy)32+ was studied. It was found that CdS QDs could enhance the anodic ECL of Ru(bpy)32+ by 4 times. The sensitization mechanism was discussed and the influence factors including concentrations of Ru(bpy)32+ and CdS QDs, pH of solution and scan rate on ECL intensity were investigated. On the basis of quenching effect of catechol on the ECL signal of CdS QDs-Ru(bpy)32+, a system for sensitive determination of catechol was established with a detection limit of 5.5 nmol/L (S/N=3). This method was applied to the detection of catechol in tea sample with satisfactory results.
2018, 46(5): 787-795
doi: 10.11895/j.issn.0253-3820.171045
Abstract:
A sample pretreatment method combining column clean-up with dispersive liquid-liquid microextraction (CCU-DLLME) for determination of polycyclic aromatic hydrocarbons (PAHs) in oil-field water was proposed. With this method, most organic interferences in matrix were cleaned up, and PAHs were purified, enriched and analyzed by gas chromatography/mass spectrometry directly. The influences on extraction efficiency including the kinds of column packing, weight ratio between column packing and sample, column flow rate, type and volume of extraction solvent, type and volume of disperser solvent and extraction time were investigated, respectively. Finally, 12 g of H103 macroporous resin was selected as column packing, 12:5 of weight ratio between column packing and sample and 4 BV/h of column flow rate were selected in CCU. The resulting eluate was added with 1.00 mL of acetone (disperser solvent) and 15 μL of carbon tetrachloride (extraction solvent), followed by DLLME for 2 min. Under the optimum conditions, the enrichment factor of PAHs was 730-1579, the limits of detection (S/N=3) were 1.1-5.3 ng/L, the linear range was 0.01-50 μg/L, the RSDs (n=5) were 0.6%-3.4% and the recoveries were 82.6%-104.6%. This method could greatly reduce the influence of organic interferences in matrix, and was fit for the rapid analysis of pollutants in oil-field water especially.
A sample pretreatment method combining column clean-up with dispersive liquid-liquid microextraction (CCU-DLLME) for determination of polycyclic aromatic hydrocarbons (PAHs) in oil-field water was proposed. With this method, most organic interferences in matrix were cleaned up, and PAHs were purified, enriched and analyzed by gas chromatography/mass spectrometry directly. The influences on extraction efficiency including the kinds of column packing, weight ratio between column packing and sample, column flow rate, type and volume of extraction solvent, type and volume of disperser solvent and extraction time were investigated, respectively. Finally, 12 g of H103 macroporous resin was selected as column packing, 12:5 of weight ratio between column packing and sample and 4 BV/h of column flow rate were selected in CCU. The resulting eluate was added with 1.00 mL of acetone (disperser solvent) and 15 μL of carbon tetrachloride (extraction solvent), followed by DLLME for 2 min. Under the optimum conditions, the enrichment factor of PAHs was 730-1579, the limits of detection (S/N=3) were 1.1-5.3 ng/L, the linear range was 0.01-50 μg/L, the RSDs (n=5) were 0.6%-3.4% and the recoveries were 82.6%-104.6%. This method could greatly reduce the influence of organic interferences in matrix, and was fit for the rapid analysis of pollutants in oil-field water especially.
2018, 46(5): 796-802
doi: 10.11895/j.issn.0253-3820.171282
Abstract:
A method was established for the determination of chlorpyrifos metabolites employing QuEChERS method and ultra performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UPLC-QTRAP). The urine samples were extracted by acetonitrile and then cleaned up with PSA and GCB. The samples were separated with the gradient elution of acetonitrile-0.2% ammonia water on ZORBAX Eclipse Plus C18 column. The analytes were detected by tandem mass spectrometry under negative ion mode with electrospray ionization (ESI) source and MRM-IDA-EPI mode. Under the optimized conditions, the calibration curve was linear in range of 1.0-100.0 μg/L, and the limits of detection were 0.10-0.73 μg/L. The average recoveries were 80.3%-90.1%, and RSDs were all within 10%. The developed method was simple, sensitive, accurate, and repeatable, and could avoid false positive result of samples effectively. The established method was successfully applied to determine the exposure level of chlorpyrifos metabolites in real samples of human health risk analysis. The results showed that the maximum concentration of chlorpyrifos metabolites was 54.6 μg/L. This method provided technic support for simultaneous identification and quantification of chemicals in complex matrix.
A method was established for the determination of chlorpyrifos metabolites employing QuEChERS method and ultra performance liquid chromatography-triple quadrupole-linear ion trap mass spectrometry (UPLC-QTRAP). The urine samples were extracted by acetonitrile and then cleaned up with PSA and GCB. The samples were separated with the gradient elution of acetonitrile-0.2% ammonia water on ZORBAX Eclipse Plus C18 column. The analytes were detected by tandem mass spectrometry under negative ion mode with electrospray ionization (ESI) source and MRM-IDA-EPI mode. Under the optimized conditions, the calibration curve was linear in range of 1.0-100.0 μg/L, and the limits of detection were 0.10-0.73 μg/L. The average recoveries were 80.3%-90.1%, and RSDs were all within 10%. The developed method was simple, sensitive, accurate, and repeatable, and could avoid false positive result of samples effectively. The established method was successfully applied to determine the exposure level of chlorpyrifos metabolites in real samples of human health risk analysis. The results showed that the maximum concentration of chlorpyrifos metabolites was 54.6 μg/L. This method provided technic support for simultaneous identification and quantification of chemicals in complex matrix.
