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2017 Volume 45 Issue 11
2017, 45(11): 1583-1588
doi: 10.11895/j.issn.0253-3820.171052
Abstract:
The electrospray ionization-ion mobility spectrometric (ESI-IMS) technique has the potential as an analytical separation tool in analyzing polypeptides and amino acids for fast screening unknown samples in anti-chemical and biological terror attacks. A method for detecting several polypeptides and amino acids was developed based on ESI-IMS using air as drift gas at room temperature. The ion mobility of four amino acids and two polypeptides dissolved in methanol was determined on the system at elution rate of 2μL/min. The spectra of these compounds had characteristics of finger-printing maps. The limit of detection of this instrument for Substance P could reach 855 ng/mL in 1 min. The results showed that a small, self-contained ESI-IMS instrument with reservoirs of air could be used to quickly detect and accurately identify polypeptides and amino acids.
The electrospray ionization-ion mobility spectrometric (ESI-IMS) technique has the potential as an analytical separation tool in analyzing polypeptides and amino acids for fast screening unknown samples in anti-chemical and biological terror attacks. A method for detecting several polypeptides and amino acids was developed based on ESI-IMS using air as drift gas at room temperature. The ion mobility of four amino acids and two polypeptides dissolved in methanol was determined on the system at elution rate of 2μL/min. The spectra of these compounds had characteristics of finger-printing maps. The limit of detection of this instrument for Substance P could reach 855 ng/mL in 1 min. The results showed that a small, self-contained ESI-IMS instrument with reservoirs of air could be used to quickly detect and accurately identify polypeptides and amino acids.
2017, 45(11): 1589-1594
doi: 10.11895/j.issn.0253-3820.171092
Abstract:
A multi-functional microfluidic chip with multi-orifice flow fractionation (MOFF) and magnetic capture technique was developed to specifically separate and capture the HepG2 cells in artificial samples. The chip contained a glass substrate and a polydimethylsiloxane (PDMS) microchannel cover plate. The PDMS cover plate consisted of 3 injection channels of 10-mm-long, a MOFF separation zone and a hexagonal cavity cell enrichment-detection zone. Among which, the MOFF separation zone had a total length of 20 mm and was consisted of 80 semi-rhombic shrinkage/expansion units with a length of 0.18 mm, a depth of 50 μm, a shrinkage area width of 0.06 mm, and an expansion area of 0.20 mm. The angle between each group of shrinkage/expansion units was 103.0°. In this experiment, HepG2-blood cell suspension was used as the sample. Based on the principle that the magnetic bead surface-modified c-Met antibody could specifically bind to HepG2 cells, an immunomagnetic bead (Anti-MNCs) suspension at a concentration of 50 μg/mL was prepared by surface carboxylated beads, EDC (1 mg/mL), NHS (1 mg/mL) and c-Met antibody. Under the optimized flow rate (50 μL/min), a few HepG2 in suspension samples were efficiently captured at the detection zone of chip via a magnetic field; the carbon quantum dots were prepared by microwave heating with citric acid and thiourea to label HepG2 cells which achieved in-situ fluorescence visualization of captured HepG2. Cells captured in the chip detection area were counted by microscope. The capture rate of HepG2 cells was 88.5%±6.7% (106 blood cells and 10 HepG2 cells per 500 μL). The results demonstrated that the developed multifunctional microfluidic chip may serve as a promising tool for separation and capture of tumour cells.
A multi-functional microfluidic chip with multi-orifice flow fractionation (MOFF) and magnetic capture technique was developed to specifically separate and capture the HepG2 cells in artificial samples. The chip contained a glass substrate and a polydimethylsiloxane (PDMS) microchannel cover plate. The PDMS cover plate consisted of 3 injection channels of 10-mm-long, a MOFF separation zone and a hexagonal cavity cell enrichment-detection zone. Among which, the MOFF separation zone had a total length of 20 mm and was consisted of 80 semi-rhombic shrinkage/expansion units with a length of 0.18 mm, a depth of 50 μm, a shrinkage area width of 0.06 mm, and an expansion area of 0.20 mm. The angle between each group of shrinkage/expansion units was 103.0°. In this experiment, HepG2-blood cell suspension was used as the sample. Based on the principle that the magnetic bead surface-modified c-Met antibody could specifically bind to HepG2 cells, an immunomagnetic bead (Anti-MNCs) suspension at a concentration of 50 μg/mL was prepared by surface carboxylated beads, EDC (1 mg/mL), NHS (1 mg/mL) and c-Met antibody. Under the optimized flow rate (50 μL/min), a few HepG2 in suspension samples were efficiently captured at the detection zone of chip via a magnetic field; the carbon quantum dots were prepared by microwave heating with citric acid and thiourea to label HepG2 cells which achieved in-situ fluorescence visualization of captured HepG2. Cells captured in the chip detection area were counted by microscope. The capture rate of HepG2 cells was 88.5%±6.7% (106 blood cells and 10 HepG2 cells per 500 μL). The results demonstrated that the developed multifunctional microfluidic chip may serve as a promising tool for separation and capture of tumour cells.
2017, 45(11): 1595-1599
doi: 10.11895/j.issn.0253-3820.171091
Abstract:
Acute traumatic spinal cord injury (SCI) represents one of the most devastating injuries that afflict the human body. Ascorbic acid (AA) plays an important role in mammalian central nervous system, especially in SCI. In this study, the change of AA concentration after SCI was investigated by using an on-line electrochemical method integrated with in vivo microdialysis. A microdialysis probe (2 mm in length) was implanted into the spinal cord of an anesthetized rat (Thoracic-10). Microdialysis perfusate (2 μL/min) was collected in the sample loop of an on-line injector for direct injection onto a glassy carbon electrode which was modified with the heat-treated single-walled carbon nanotubes (SWNTs). Normal ascorbic acid concentration in the extracellular fluids of spinal cords was (26.17 ±1.25) μmol/L (n=8). The experimental spinal cord injury, induced by a lesion at T-10, significantly increased the extracellular ascorbic acid levels to (53.24±1.95) μmol/L (n=8). This study provides the experimental evidence on the essential roles of ascorbic acid in spinal cord injuries.
Acute traumatic spinal cord injury (SCI) represents one of the most devastating injuries that afflict the human body. Ascorbic acid (AA) plays an important role in mammalian central nervous system, especially in SCI. In this study, the change of AA concentration after SCI was investigated by using an on-line electrochemical method integrated with in vivo microdialysis. A microdialysis probe (2 mm in length) was implanted into the spinal cord of an anesthetized rat (Thoracic-10). Microdialysis perfusate (2 μL/min) was collected in the sample loop of an on-line injector for direct injection onto a glassy carbon electrode which was modified with the heat-treated single-walled carbon nanotubes (SWNTs). Normal ascorbic acid concentration in the extracellular fluids of spinal cords was (26.17 ±1.25) μmol/L (n=8). The experimental spinal cord injury, induced by a lesion at T-10, significantly increased the extracellular ascorbic acid levels to (53.24±1.95) μmol/L (n=8). This study provides the experimental evidence on the essential roles of ascorbic acid in spinal cord injuries.
2017, 45(11): 1600-1605
doi: 10.11895/j.issn.0253-3820.160870
Abstract:
A detection method for furazolidone and florfenicol in soil with various environmental matrices was established using ultra performance liquid chromatography-tandem spectrometry (UPLC/MS/MS) technique. Extracting solution of a mixture of phosphate buffer (pH=3) and acetonitrile (3:7, V/V) was used in this experiment. The extracted water samples were enriched by SAX-HLB solid phase extraction column before the process of nitrogen blowing (high purity nitrogen). The enriched antibiotics were desalted with 8 mL of methanol. Waters BEH C18 (2.1×100 mm) column was used for the sample separation. UPLC/MS/MS was carried out for qualitative and quantitative analysis under multi-reaction monitoring mode. The detection limit of the method was determined by 3 times of signal-to-noise ratio, and the limit of determination of the method was determined by 10 times of signal-to-noise ratio. The results showed that the detection limits of furazolidone and florfenicol were 1.19 and 0.41 μg/kg, respectively, and the limits of quantitation of furazolidone and florfenicol were 3.40 and 1.37 μg/kg, respectively. Besides, recovery experiment showed that, for the soil samples spiked with 50 μg/L furazolidone and florfenicol, the recoveries were 79% for florfenicol and 92% for furazolidone. Similarly, for the soil samples spiked with 200 μg/L furazolidone and florfenicol, the recoveries were 96% for furazolidone and 86% for florfenicol.
A detection method for furazolidone and florfenicol in soil with various environmental matrices was established using ultra performance liquid chromatography-tandem spectrometry (UPLC/MS/MS) technique. Extracting solution of a mixture of phosphate buffer (pH=3) and acetonitrile (3:7, V/V) was used in this experiment. The extracted water samples were enriched by SAX-HLB solid phase extraction column before the process of nitrogen blowing (high purity nitrogen). The enriched antibiotics were desalted with 8 mL of methanol. Waters BEH C18 (2.1×100 mm) column was used for the sample separation. UPLC/MS/MS was carried out for qualitative and quantitative analysis under multi-reaction monitoring mode. The detection limit of the method was determined by 3 times of signal-to-noise ratio, and the limit of determination of the method was determined by 10 times of signal-to-noise ratio. The results showed that the detection limits of furazolidone and florfenicol were 1.19 and 0.41 μg/kg, respectively, and the limits of quantitation of furazolidone and florfenicol were 3.40 and 1.37 μg/kg, respectively. Besides, recovery experiment showed that, for the soil samples spiked with 50 μg/L furazolidone and florfenicol, the recoveries were 79% for florfenicol and 92% for furazolidone. Similarly, for the soil samples spiked with 200 μg/L furazolidone and florfenicol, the recoveries were 96% for furazolidone and 86% for florfenicol.
2017, 45(11): 1606-1612
doi: 10.11895/j.issn.0253-3820.170355
Abstract:
Trace level of fructose was successfully detected by a sensor, in which the phosphorescence of Mn-doped ZnS (Mn-ZnS) room-temperature phosphorescence (RTP) quantum dots (QDs) was used as signals, and boronic acid-substituted bipyridinium salt (BBV) synthesized from 2-(bromomethyl) phenylboronic acid and 4,4'-bipyridyl was used as the receptor. The negatively-charged Mn-ZnS QDs and the positively-charged BBV electrostatically attracted each other to form Mn-ZnS QDs/BBV nanohybrids, which quenched the RTP of Mn-ZnS QDs. After addition into these nanohybrids, the fructose bonded with BBV to form an anionic borate, which largely restricted the quenching of BBV on Mn-ZnS QDs, thus the RTP was restored. In this work, we investigated the effects of pH and reaction time on the RTP of the Mn-ZnS QDs/BBV nanohybrids. Under the optimal conditions, the novel probe had a fructose detection limit of 0.01 mmol/L and a linear range of 0.05-1.0 mmol/L was achieved with correlation coefficient of 0.99. This phosphorescence sensor was superior with convenience and high speed, and can be potentially applied to the detection and analysis of fructose in foods and medicine fields.
Trace level of fructose was successfully detected by a sensor, in which the phosphorescence of Mn-doped ZnS (Mn-ZnS) room-temperature phosphorescence (RTP) quantum dots (QDs) was used as signals, and boronic acid-substituted bipyridinium salt (BBV) synthesized from 2-(bromomethyl) phenylboronic acid and 4,4'-bipyridyl was used as the receptor. The negatively-charged Mn-ZnS QDs and the positively-charged BBV electrostatically attracted each other to form Mn-ZnS QDs/BBV nanohybrids, which quenched the RTP of Mn-ZnS QDs. After addition into these nanohybrids, the fructose bonded with BBV to form an anionic borate, which largely restricted the quenching of BBV on Mn-ZnS QDs, thus the RTP was restored. In this work, we investigated the effects of pH and reaction time on the RTP of the Mn-ZnS QDs/BBV nanohybrids. Under the optimal conditions, the novel probe had a fructose detection limit of 0.01 mmol/L and a linear range of 0.05-1.0 mmol/L was achieved with correlation coefficient of 0.99. This phosphorescence sensor was superior with convenience and high speed, and can be potentially applied to the detection and analysis of fructose in foods and medicine fields.
2017, 45(11): 1613-1620
doi: 10.11895/j.issn.0253-3820.170341
Abstract:
The binding mechanism between pterostilbene (PTE) and human serum albumin (HSA) was investigated by fluorescence spectrometry and surface enhanced Raman spectroscopy (SERS) under simulated physiological conditions. The experiment result showed that the effect between PTE and HSA was a static fluorescence quenching with Förster's non-radioactive energy transformation, and PTE could bind HSA strongly with a 1:1 molar ratio. The binding distances between PTE and HSA was 1.495 nm, and the binding constants (KA) between PTE and HSA were 1.12×104 (298 K), 4.07×104 (304 K) and 2.45×105 L/mol (310 K). SERS revealed that PTE combined with HAS by methoxy group. Thermodynamic data indicated that the interaction between PTE and HSA was mainly hydrophobic interaction. Marker competition experiments pointed out that the primary binding site for PTE was located at site Ⅲ in HSA. Three-dimensional, synchronous fluorescence spectrum and SERS showed that the conformation of HSA changed apparently with the addition of PTE, resulting in the tryptophan residue of HSA exposing to a less hydrophobic micro-environment. However, the conformation of PTE did not change apparently with the addition of HSA.
The binding mechanism between pterostilbene (PTE) and human serum albumin (HSA) was investigated by fluorescence spectrometry and surface enhanced Raman spectroscopy (SERS) under simulated physiological conditions. The experiment result showed that the effect between PTE and HSA was a static fluorescence quenching with Förster's non-radioactive energy transformation, and PTE could bind HSA strongly with a 1:1 molar ratio. The binding distances between PTE and HSA was 1.495 nm, and the binding constants (KA) between PTE and HSA were 1.12×104 (298 K), 4.07×104 (304 K) and 2.45×105 L/mol (310 K). SERS revealed that PTE combined with HAS by methoxy group. Thermodynamic data indicated that the interaction between PTE and HSA was mainly hydrophobic interaction. Marker competition experiments pointed out that the primary binding site for PTE was located at site Ⅲ in HSA. Three-dimensional, synchronous fluorescence spectrum and SERS showed that the conformation of HSA changed apparently with the addition of PTE, resulting in the tryptophan residue of HSA exposing to a less hydrophobic micro-environment. However, the conformation of PTE did not change apparently with the addition of HSA.
2017, 45(11): 1621-1627
doi: 10.11895/j.issn.0253-3820.170221
Abstract:
CeO2-Co3O4 composite nanofibers were prepared by the double jets electrospinning method. The nanofibers were then deposited onto the surface of a μ-type heating coil as cataluminescence material to prepare a new cataluminescence (CTL) type formaldehyde gas sensor. The crystalline phase and microstructure of CeO2-Co3O4 composite nanofibers were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the cataluminescence mechanism and electrochemical characteristic of formaldehyde on the surface of CeO2-Co3O4 nanofibers were analyzed by H2 temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). Under the optimal conditions (500 nm of wavelength, 0.2 L/min of flow rate and 550℃), there was a good relationship between the CTL intensity of this formaldehyde gas sensor (Ce30) and formaldehyde concentration in the range of 1.2-50 μg/m3, the sensitivity was 40.04 a.u./(μg/m3), the detection limit was 1.2 μg/m3, the dynamic response time and recover time of formaldehyde gas were 2.4 s and 3.5 s, respectively. The formaldehyde sensor was successfully applied to the determination of formaldehyde in the automotive exhaust, with relative errors of 0.39%-1.07% and relative standard deviations of less than 3%.
CeO2-Co3O4 composite nanofibers were prepared by the double jets electrospinning method. The nanofibers were then deposited onto the surface of a μ-type heating coil as cataluminescence material to prepare a new cataluminescence (CTL) type formaldehyde gas sensor. The crystalline phase and microstructure of CeO2-Co3O4 composite nanofibers were characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM), and the cataluminescence mechanism and electrochemical characteristic of formaldehyde on the surface of CeO2-Co3O4 nanofibers were analyzed by H2 temperature programmed reduction (H2-TPR) and X-ray photoelectron spectroscopy (XPS). Under the optimal conditions (500 nm of wavelength, 0.2 L/min of flow rate and 550℃), there was a good relationship between the CTL intensity of this formaldehyde gas sensor (Ce30) and formaldehyde concentration in the range of 1.2-50 μg/m3, the sensitivity was 40.04 a.u./(μg/m3), the detection limit was 1.2 μg/m3, the dynamic response time and recover time of formaldehyde gas were 2.4 s and 3.5 s, respectively. The formaldehyde sensor was successfully applied to the determination of formaldehyde in the automotive exhaust, with relative errors of 0.39%-1.07% and relative standard deviations of less than 3%.
2017, 45(11): 1628-1634
doi: 10.11895/j.issn.0253-3820.171010
Abstract:
Rapid discrimination of compounds with similar structures and properties is a hot topic in analytical chemistry. In this study, a cyclic chemiluminescence (CCL) system was designed by using nano-magnesium oxide as catalyst. The effects of reactant concentration, reaction temperature and detection wavelength on CCL analysis were studied. It was found that the CCL signal satisfied the first order exponential decay law. Each reaction had an exponential decay equation (EDE) describing its signal change law. The initial variable A was proportional to the reactant concentration. The decay-coefficient k was a characteristic constant that was independent of the reactant concentration. For iso-butanol, it's A-values versus concentration was linear in 0.89-14.24 mg/L, the average of k-value in this range was 32.0 with a RSD of 2.2%. Thus, qualitative and quantitative analysis could be conducted according to the A and k values. The system was used to analyze eight kinds of alcohol compounds, and it was found that there were significant differences in the k-values for different alcohols. For example, the k-values for n-butanol, iso-butanol and sec-butanol were 27.2±0.2, 32.0±0.8 and 19.5±0.1, respectively.
Rapid discrimination of compounds with similar structures and properties is a hot topic in analytical chemistry. In this study, a cyclic chemiluminescence (CCL) system was designed by using nano-magnesium oxide as catalyst. The effects of reactant concentration, reaction temperature and detection wavelength on CCL analysis were studied. It was found that the CCL signal satisfied the first order exponential decay law. Each reaction had an exponential decay equation (EDE) describing its signal change law. The initial variable A was proportional to the reactant concentration. The decay-coefficient k was a characteristic constant that was independent of the reactant concentration. For iso-butanol, it's A-values versus concentration was linear in 0.89-14.24 mg/L, the average of k-value in this range was 32.0 with a RSD of 2.2%. Thus, qualitative and quantitative analysis could be conducted according to the A and k values. The system was used to analyze eight kinds of alcohol compounds, and it was found that there were significant differences in the k-values for different alcohols. For example, the k-values for n-butanol, iso-butanol and sec-butanol were 27.2±0.2, 32.0±0.8 and 19.5±0.1, respectively.
2017, 45(11): 1635-1640
doi: 10.11895/j.issn.0253-3820.170227
Abstract:
A rapid detection method for dyeing wastewater by snapshot imaging spectrometer was developed. The simulated dyeing wastewater solution of a single component and mixed components was prepared and the experimental conditions were optimized. The white LED array was used as the detection light source and the image of the sample was collected by the imaging spectrometer developed in the laboratory to obtain the spectral information of the sample in the range of 400-800 nm. The standard curve between the absorbance and the concentration of the samples was established. The linear range of a single component of Rhodamine B or Orange G was 1-50 mg/L, the linear correlation coefficients was more than 0.99, the recoveries were 93%-114% and the relative standard deviations (RSD) were 7.5% and 1.3%. The correlation coefficients between predicted concentration and reference concentration reached 0.999 in the detection of mixed component by using the multiple linear regression model, and the relative errors of 3 predicted samples were reduced. The rapid, accurate and precise method showed an excellent promise for on-site and emergency detection of dyeing wastewater.
A rapid detection method for dyeing wastewater by snapshot imaging spectrometer was developed. The simulated dyeing wastewater solution of a single component and mixed components was prepared and the experimental conditions were optimized. The white LED array was used as the detection light source and the image of the sample was collected by the imaging spectrometer developed in the laboratory to obtain the spectral information of the sample in the range of 400-800 nm. The standard curve between the absorbance and the concentration of the samples was established. The linear range of a single component of Rhodamine B or Orange G was 1-50 mg/L, the linear correlation coefficients was more than 0.99, the recoveries were 93%-114% and the relative standard deviations (RSD) were 7.5% and 1.3%. The correlation coefficients between predicted concentration and reference concentration reached 0.999 in the detection of mixed component by using the multiple linear regression model, and the relative errors of 3 predicted samples were reduced. The rapid, accurate and precise method showed an excellent promise for on-site and emergency detection of dyeing wastewater.
2017, 45(11): 1641-1647
doi: 10.11895/j.issn.0253-3820.170262
Abstract:
A method for determination of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in atmospheric fine particles (PM2.5) was developed based on accelerated solvent extraction-direct injection coupled with high performance liquid chromatography (HPLC). PM2.5 was collected by glass fiber membrane filter and pretreated with acetonitrile by accelerated solvent extraction. The extract was separated by ZORBAX Eclipse PAH column with acetonitrile and water as mobile phase, and detected by ultraviolet and fluorescence detectors. The result showed that the 16 kinds of PAHs were well separated and there were good linear relationships (r ≥ 0.9998) in the concentration range of 0.025-5.00 μg/mL. The recoveries were from 78.3% to 113.2%. The relative standard deviations ranged from 0.5% to 9.5%. The detection limits were 0.007-0.062 ng/m3. The method was simple, rapid, accurate and sensitive, and suitable for the simultaneous determination of 16 kinds of PAHS in PM2.5.
A method for determination of 16 kinds of polycyclic aromatic hydrocarbons (PAHs) in atmospheric fine particles (PM2.5) was developed based on accelerated solvent extraction-direct injection coupled with high performance liquid chromatography (HPLC). PM2.5 was collected by glass fiber membrane filter and pretreated with acetonitrile by accelerated solvent extraction. The extract was separated by ZORBAX Eclipse PAH column with acetonitrile and water as mobile phase, and detected by ultraviolet and fluorescence detectors. The result showed that the 16 kinds of PAHs were well separated and there were good linear relationships (r ≥ 0.9998) in the concentration range of 0.025-5.00 μg/mL. The recoveries were from 78.3% to 113.2%. The relative standard deviations ranged from 0.5% to 9.5%. The detection limits were 0.007-0.062 ng/m3. The method was simple, rapid, accurate and sensitive, and suitable for the simultaneous determination of 16 kinds of PAHS in PM2.5.
2017, 45(11): 1648-1654
doi: 10.11895/j.issn.0253-3820.171027
Abstract:
A simple method was developed for simultaneous determination of seven urinary metabolites of organophosphate esters by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on different physical and chemical properties of these OPs metabolites, the solid phase extraction cartridges and the washing and eluting solvents were optimized in details. Furthermore, the mobile phase and mass spectrometric parameters were also investigated. The results showed that Oasis WAX cartridge was the best SPE column in this study, and 2 mL of NH3·H2O (5%) in methanol and 2 mL of methanol were chosen as the eluting solvents. The recoveries of six analytes were ranged from 60.5% to 104.0%, whereas DEP ranged from 17.8% to 36.2%. Seven analytes could be baseline separated from each other under the optimized chromatographic conditions. The limits of detection and quantification of seven analytes ranged from 0.005 to 0.2 μg/L and 0.02 to 0.5 μg/L, respectively. The standard deviations of response repeatability for intra-day and inter-day period were lower than 15.4%. This method was finally applied to determination of metabolites of OPs from 10 urines from general population in Guangzhou city. The concentrations of total OPs metabolites in urine samples ranged from 0.5 to 6.7 μg/L.
A simple method was developed for simultaneous determination of seven urinary metabolites of organophosphate esters by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Based on different physical and chemical properties of these OPs metabolites, the solid phase extraction cartridges and the washing and eluting solvents were optimized in details. Furthermore, the mobile phase and mass spectrometric parameters were also investigated. The results showed that Oasis WAX cartridge was the best SPE column in this study, and 2 mL of NH3·H2O (5%) in methanol and 2 mL of methanol were chosen as the eluting solvents. The recoveries of six analytes were ranged from 60.5% to 104.0%, whereas DEP ranged from 17.8% to 36.2%. Seven analytes could be baseline separated from each other under the optimized chromatographic conditions. The limits of detection and quantification of seven analytes ranged from 0.005 to 0.2 μg/L and 0.02 to 0.5 μg/L, respectively. The standard deviations of response repeatability for intra-day and inter-day period were lower than 15.4%. This method was finally applied to determination of metabolites of OPs from 10 urines from general population in Guangzhou city. The concentrations of total OPs metabolites in urine samples ranged from 0.5 to 6.7 μg/L.
2017, 45(11): 1655-1661
doi: 10.11895/j.issn.0253-3820.170333
Abstract:
The effective exploitation of natural products is of great significance. Herein the essential oil from Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period was extracted by ethanol extraction method. The optimal extraction condition was determined by orthogonal experiment, including extracting 3 times, soaking for 90 min, and the ratios of liquid to solid for Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period were 10 mL:1 g and 8 mL:1 g, respectively. The main components of the products were confirmed by FT-IR and GC-MS, which were cineole, camphor, d-borneol, caryophyllene, cadina-1, 4-diene, calamenene, ethyl palmitate, etc. in herba artimisiae sieversianae in growth period, and camphor, caryophyllene, borneol, neryl formate, etc. in Herba Artimisiae Sieversianae in flower/fruit bearing period. The radical scavenging activity of the products was determined. The results showed that the IC50 values of the essential oil from Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period for 0.05 mmol/L DPPH solution were 0.40 mg/mL and 1.66 mg/mL, respectively. The essential oil extracted by ethanol from Herba Artimisiae Sieversianae was confirmed to possess good antioxidant activity.
The effective exploitation of natural products is of great significance. Herein the essential oil from Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period was extracted by ethanol extraction method. The optimal extraction condition was determined by orthogonal experiment, including extracting 3 times, soaking for 90 min, and the ratios of liquid to solid for Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period were 10 mL:1 g and 8 mL:1 g, respectively. The main components of the products were confirmed by FT-IR and GC-MS, which were cineole, camphor, d-borneol, caryophyllene, cadina-1, 4-diene, calamenene, ethyl palmitate, etc. in herba artimisiae sieversianae in growth period, and camphor, caryophyllene, borneol, neryl formate, etc. in Herba Artimisiae Sieversianae in flower/fruit bearing period. The radical scavenging activity of the products was determined. The results showed that the IC50 values of the essential oil from Herba Artimisiae Sieversianae in growth period and flower/fruit bearing period for 0.05 mmol/L DPPH solution were 0.40 mg/mL and 1.66 mg/mL, respectively. The essential oil extracted by ethanol from Herba Artimisiae Sieversianae was confirmed to possess good antioxidant activity.
2017, 45(11): 1662-1668
doi: 10.11895/j.issn.0253-3820.171038
Abstract:
Hydrothermal oxidation was used to prepare a nickel-titanium alloy (NiTi) solid-phase microextraction fiber. The experimental results demonstrated that a nanoporous NiTi oxide composite coating was in situ grown on the surface of NiTi substrate by direct oxidation in aqueous H2O2 solution at 80℃. The resulting composite oxide coating included more nickel and less titanium. The prepared NiTi fiber with Ni-rich oxide coating was used to extract typical aromatic compounds coupled with HPLC-UV and exhibited good extraction selectivity for polycyclic aromatic hydrocarbons (PAHs). The key factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0.05 to 500 ng/mL with correlation coefficients ≥ 0.999, and the limits of detection were 0.026-0.056 ng/mL. Furthermore, the relative standard deviations (RSDs) for intra-day and inter-day repeatability of the single fiber varied from 4.8% to 6.2% and from 5.4% to 6.5% for five replicates of PAHs at the spiking level of 50 ng/mL, respectively. The RSDs for the fiber-to-fiber reproducibility of five fibers prepared in different batches ranged from 6.4% to 8.4%. This method was suitable for selective enrichment and detection of target PAHs in environmental water samples with relative recoveries of 87.4%-108.2% and RSDs<8.1%. Moreover, this novel NiTi fiber was mechanically strong and chemically stable, and its preparation was precisely controllable.
Hydrothermal oxidation was used to prepare a nickel-titanium alloy (NiTi) solid-phase microextraction fiber. The experimental results demonstrated that a nanoporous NiTi oxide composite coating was in situ grown on the surface of NiTi substrate by direct oxidation in aqueous H2O2 solution at 80℃. The resulting composite oxide coating included more nickel and less titanium. The prepared NiTi fiber with Ni-rich oxide coating was used to extract typical aromatic compounds coupled with HPLC-UV and exhibited good extraction selectivity for polycyclic aromatic hydrocarbons (PAHs). The key factors affecting extraction efficiency of PAHs were examined. Under the optimized conditions, the calibration curves were linear in the range from 0.05 to 500 ng/mL with correlation coefficients ≥ 0.999, and the limits of detection were 0.026-0.056 ng/mL. Furthermore, the relative standard deviations (RSDs) for intra-day and inter-day repeatability of the single fiber varied from 4.8% to 6.2% and from 5.4% to 6.5% for five replicates of PAHs at the spiking level of 50 ng/mL, respectively. The RSDs for the fiber-to-fiber reproducibility of five fibers prepared in different batches ranged from 6.4% to 8.4%. This method was suitable for selective enrichment and detection of target PAHs in environmental water samples with relative recoveries of 87.4%-108.2% and RSDs<8.1%. Moreover, this novel NiTi fiber was mechanically strong and chemically stable, and its preparation was precisely controllable.
2017, 45(11): 1669-1677
doi: 10.11895/j.issn.0253-3820.170224
Abstract:
Porous carbon nanoparticles (NPC) were prepared by ZnCl2 activation and carbonization using citrus waste as carbon source. A sample pretreatment method with NPC as dispersive solid phase extraction (d-SPE) absorbent was established for the determination of organophosphorus pesticides in fruits and vegetables by gas chromatography. The NPC was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), FT-IR spectra, Raman spectroscopy, Brunauer, Emmett and Teller surface area (BET). Those results showed that the NPC was an amorphous porous carbon material with pore size in the range of 0-15 nm. Its specific surface area and pore volume were 1243 m2/g and 1.28 cm3/g, respectively. The analysis conditions, including the amount and clean up time of adsorbent, were optimized by analysis of 14 kinds of oranophosphorus pesticides in fruits and vegetables with gas chromatography-flame photometric determination(GC-FPD). Moreover, the comparison for NPC with commercial materials of PSA, C18 and GCB was investigated in this study. The results indicated that the purification time was only 2 min using 0.01 g NPC. The cost of NPC was about 25% of C18, 21% of PSA and 16% of GCB. Because of the porous structure of NPC, the purification efficiency was significantly higher than the three commercial materials mentioned above. Under the optimum conditions, the calibration curves of the 14 organophosphorus pesticides were linear in the range of 0.02-1.00 mg/L with good correlation coefficients (R2>0.99) and detection limits (S/N=3) of 0.63-5.30 μg/kg. The recoveries of the pesticides at three spiked levels ranged from 71.3% to 114.7% with the relative standard deviations (RSDs) of 0.9%-12.9%. The method is simple, rapid, sensitive, and low cost, and can satisfy the requirements of detection of organophosphorus pesticide residues in fruits and vegetables, displaying a good application prospect.
Porous carbon nanoparticles (NPC) were prepared by ZnCl2 activation and carbonization using citrus waste as carbon source. A sample pretreatment method with NPC as dispersive solid phase extraction (d-SPE) absorbent was established for the determination of organophosphorus pesticides in fruits and vegetables by gas chromatography. The NPC was characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), FT-IR spectra, Raman spectroscopy, Brunauer, Emmett and Teller surface area (BET). Those results showed that the NPC was an amorphous porous carbon material with pore size in the range of 0-15 nm. Its specific surface area and pore volume were 1243 m2/g and 1.28 cm3/g, respectively. The analysis conditions, including the amount and clean up time of adsorbent, were optimized by analysis of 14 kinds of oranophosphorus pesticides in fruits and vegetables with gas chromatography-flame photometric determination(GC-FPD). Moreover, the comparison for NPC with commercial materials of PSA, C18 and GCB was investigated in this study. The results indicated that the purification time was only 2 min using 0.01 g NPC. The cost of NPC was about 25% of C18, 21% of PSA and 16% of GCB. Because of the porous structure of NPC, the purification efficiency was significantly higher than the three commercial materials mentioned above. Under the optimum conditions, the calibration curves of the 14 organophosphorus pesticides were linear in the range of 0.02-1.00 mg/L with good correlation coefficients (R2>0.99) and detection limits (S/N=3) of 0.63-5.30 μg/kg. The recoveries of the pesticides at three spiked levels ranged from 71.3% to 114.7% with the relative standard deviations (RSDs) of 0.9%-12.9%. The method is simple, rapid, sensitive, and low cost, and can satisfy the requirements of detection of organophosphorus pesticide residues in fruits and vegetables, displaying a good application prospect.
2017, 45(11): 1678-1685
doi: 10.11895/j.issn.0253-3820.170170
Abstract:
The bevacizumab and its glycoforms were analyzed by matrix-assisted laser desorption ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-MS), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and short-gun strategy, with the sequence of unique peptide and seventeen glycoforms being characterized. The bevacizumab and its glycopeptides concentrations in mice plasma with different intravenous injection doses of bevacizumab were detected and the concentration-time curves were obtained by parallel reaction monitoring (PRM) method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique. First, standard curves were created for quantification of mAb in mice plasma, which showed good linearity, with the correlation coefficient (R2) value of 0.998 and the lower limit of quantification of 66 fmol. Detection results of high and low doses of the drug in the mice plasma samples showed that the drug concentration-time curve trend was consistent, e.g. the concentration was decreasing. However, the results of quantitation of seventeen glycoforms demonstrated that the metabolism of different glycoforms was different. The concentrations of most glycoforms increased first, whereas the metabolism afterwards differed by different glycoforms.
The bevacizumab and its glycoforms were analyzed by matrix-assisted laser desorption ionization-time of flight-time of flight-mass spectrometry (MALDI-TOF-MS), sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and short-gun strategy, with the sequence of unique peptide and seventeen glycoforms being characterized. The bevacizumab and its glycopeptides concentrations in mice plasma with different intravenous injection doses of bevacizumab were detected and the concentration-time curves were obtained by parallel reaction monitoring (PRM) method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) technique. First, standard curves were created for quantification of mAb in mice plasma, which showed good linearity, with the correlation coefficient (R2) value of 0.998 and the lower limit of quantification of 66 fmol. Detection results of high and low doses of the drug in the mice plasma samples showed that the drug concentration-time curve trend was consistent, e.g. the concentration was decreasing. However, the results of quantitation of seventeen glycoforms demonstrated that the metabolism of different glycoforms was different. The concentrations of most glycoforms increased first, whereas the metabolism afterwards differed by different glycoforms.
2017, 45(11): 1686-1693
doi: 10.11895/j.issn.0253-3820.170300
Abstract:
A fluorescent immunochromatographic test strip based on the quantum dots submicrobeads (QBs) was developed for quantitative detection of chloramphenicol (CAP). In this method, monoclonal antibody of CAP and OBs complex fluorescent probe was first prepared using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide coupling approach, then complete antigen CAP-HS-BSA was synthesized and sprayed on nitrocellulose membrane as test line (T line). Similarly, goat anti-mouse antibody was sprayed as control line (C line). The time required for the analysis was 15 min, and the limit of detection (LOD) for CAP was 0.1 μg/L, with a working range of 0.1-100 μg/L. In spiked milk samples, the test strip demonstrated high recoveries in the range from 93.3% to 97.9% with relative standard deviations of less than 7%.
A fluorescent immunochromatographic test strip based on the quantum dots submicrobeads (QBs) was developed for quantitative detection of chloramphenicol (CAP). In this method, monoclonal antibody of CAP and OBs complex fluorescent probe was first prepared using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxysuccinimide coupling approach, then complete antigen CAP-HS-BSA was synthesized and sprayed on nitrocellulose membrane as test line (T line). Similarly, goat anti-mouse antibody was sprayed as control line (C line). The time required for the analysis was 15 min, and the limit of detection (LOD) for CAP was 0.1 μg/L, with a working range of 0.1-100 μg/L. In spiked milk samples, the test strip demonstrated high recoveries in the range from 93.3% to 97.9% with relative standard deviations of less than 7%.
2017, 45(11): 1694-1702
doi: 10.11895/j.issn.0253-3820.170329
Abstract:
Near infrared spectroscopy (NIR) was used to detect trans fatty acids (TFA) in edible vegetable oils quantitatively. And prediction model of TFA was optimized through band selection, pretreatment method, variable selection and modeling method. NIR spectra of 98 edible vegetable oil samples were collected in spectral range of 4000-10000 cm-1 using an Antaris Ⅱ Fourier transform near infrared spectrometer, and the true content of TFA was measured by gas chromatography. First, optimization of waveband and pretreatment method was conducted on original spectra. On this basis, competitive adaptive reweighted sampling (CARS) was used to select important variables that related to TFA. Finally, the prediction models of TFA content in edible vegetable oils were established using principal component regression (PCR), partial least square (PLS) and least square support vector machine (LS-SVM). The results indicated that NIR spectroscopy was feasible for detecting TFA content in edible vegetable oils, R2 of the best prediction model after optimized in calibration and prediction sets were 0.992 and 0.989, and root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were 0.071% and 0.075%, respectively. Only 26 variables were used in the best prediction model, accounting for 0.854% of the whole waveband variables. In addition, compared with the full waveband PLS prediction model, the R2 in prediction set increased from 0.904 to 0.989, and RMSEP decreased from 0.230% to 0.075%. It shows that model optimization is very necessary, CARS method can select important variables related to TFA effectively and immensely reduce the number of modeling variables, so it can simplify the prediction model, and greatly improve the accuracy and stability of prediction model.
Near infrared spectroscopy (NIR) was used to detect trans fatty acids (TFA) in edible vegetable oils quantitatively. And prediction model of TFA was optimized through band selection, pretreatment method, variable selection and modeling method. NIR spectra of 98 edible vegetable oil samples were collected in spectral range of 4000-10000 cm-1 using an Antaris Ⅱ Fourier transform near infrared spectrometer, and the true content of TFA was measured by gas chromatography. First, optimization of waveband and pretreatment method was conducted on original spectra. On this basis, competitive adaptive reweighted sampling (CARS) was used to select important variables that related to TFA. Finally, the prediction models of TFA content in edible vegetable oils were established using principal component regression (PCR), partial least square (PLS) and least square support vector machine (LS-SVM). The results indicated that NIR spectroscopy was feasible for detecting TFA content in edible vegetable oils, R2 of the best prediction model after optimized in calibration and prediction sets were 0.992 and 0.989, and root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were 0.071% and 0.075%, respectively. Only 26 variables were used in the best prediction model, accounting for 0.854% of the whole waveband variables. In addition, compared with the full waveband PLS prediction model, the R2 in prediction set increased from 0.904 to 0.989, and RMSEP decreased from 0.230% to 0.075%. It shows that model optimization is very necessary, CARS method can select important variables related to TFA effectively and immensely reduce the number of modeling variables, so it can simplify the prediction model, and greatly improve the accuracy and stability of prediction model.
2017, 45(11): 1703-1710
doi: 10.11895/j.issn.0253-3820.170339
Abstract:
An online solid phase extraction (online-SPE) combined with ultra high performance liquid chromatography-quadrupole linear ion trap mass spectrometry (UHPLC-MS/MS-Qtrap) was established for the simultaneous identification and determination of 10 kinds of algal toxins in water samples. Multiple injections of water samples were controlled by a preset program, and the target analytes were enriched by trap column. The six-way valve was switched subsequently, and the algal toxins in the trap column were back-flushed to the analytical column for separation and analysis. The results showed that the online SPE significantly simplified pretreatment process, and the linear ion trap tandem mass spectrometry improved the sensitivity of the determination. Moreover, the establishment of enhanced product ion (EPI) scan library provided evidence for the confirmation of algal toxins. The 10 kinds of algal toxins showed a good linear relationship with correlation coefficient R2>0.99. The limits of detection (LOD) were 0.0015-0.0050 μg/L. The mean recoveries at three spiked levels of 0.02, 0.1, 1.0 μg/L were from 83.7% to 98.5%. The method was suitable for the rapid confirmation and quantitative determination of various algal toxins in water.
An online solid phase extraction (online-SPE) combined with ultra high performance liquid chromatography-quadrupole linear ion trap mass spectrometry (UHPLC-MS/MS-Qtrap) was established for the simultaneous identification and determination of 10 kinds of algal toxins in water samples. Multiple injections of water samples were controlled by a preset program, and the target analytes were enriched by trap column. The six-way valve was switched subsequently, and the algal toxins in the trap column were back-flushed to the analytical column for separation and analysis. The results showed that the online SPE significantly simplified pretreatment process, and the linear ion trap tandem mass spectrometry improved the sensitivity of the determination. Moreover, the establishment of enhanced product ion (EPI) scan library provided evidence for the confirmation of algal toxins. The 10 kinds of algal toxins showed a good linear relationship with correlation coefficient R2>0.99. The limits of detection (LOD) were 0.0015-0.0050 μg/L. The mean recoveries at three spiked levels of 0.02, 0.1, 1.0 μg/L were from 83.7% to 98.5%. The method was suitable for the rapid confirmation and quantitative determination of various algal toxins in water.
2017, 45(11): 1711-1718
doi: 10.11895/j.issn.0253-3820.171160
Abstract:
A method for the determination of 15 kinds of nitroaromatics in aqueous samples was developed by dispersive liquid-liquid microextraction and gas chromatography with electron capture detection. A high-density extractant applied in electron capture detector was screened out. The chromatographic conditions, types and dosages of extractants, types and dosages of dispersants, extraction time and the extraction temperature were optimized. The results showed that DB-35 capillary column had the best separation performance for the 15 kinds of nitroaromatics. The nitroaromatics could be separated within 22 min using programmed temperature control as follows:holding at an initial temperature of 80℃ and then heating to 180℃ at a ramping rate of 5℃/min. For the extraction of 15 kinds of nitroaromatics from 5 mL of aqueous sample, the extraction equilibrium could be reached within 30 s with a high extraction recovery of over 90% when using 100 μL of chlorobenzene as extracting solvent and 400 μL of methanol as disperser solvent. In addition, the enrichment factor could approach a high value of 45.0-48.8. The sediment collected by centrifugation was injected and analyzed by gas chromatography with electron capture detector. The limits of quantification of the developed method were 0.03-0.15 μg/L (S/N=10). The linear range was from 0.20 μg/L to 50.0 μg/L, while the correlation coefficients (R2) were more than 0.998. At the spiked level of 0.200 μg/L, the relative standard deviations of this method were 3.3%-8.9%, the relative recoveries ranged from 86.0% to 103.5%. At higher spiked level, the relative standard deviations were less than 5%, and the relative recoveries ranged from 94.5% to 101.5%.
A method for the determination of 15 kinds of nitroaromatics in aqueous samples was developed by dispersive liquid-liquid microextraction and gas chromatography with electron capture detection. A high-density extractant applied in electron capture detector was screened out. The chromatographic conditions, types and dosages of extractants, types and dosages of dispersants, extraction time and the extraction temperature were optimized. The results showed that DB-35 capillary column had the best separation performance for the 15 kinds of nitroaromatics. The nitroaromatics could be separated within 22 min using programmed temperature control as follows:holding at an initial temperature of 80℃ and then heating to 180℃ at a ramping rate of 5℃/min. For the extraction of 15 kinds of nitroaromatics from 5 mL of aqueous sample, the extraction equilibrium could be reached within 30 s with a high extraction recovery of over 90% when using 100 μL of chlorobenzene as extracting solvent and 400 μL of methanol as disperser solvent. In addition, the enrichment factor could approach a high value of 45.0-48.8. The sediment collected by centrifugation was injected and analyzed by gas chromatography with electron capture detector. The limits of quantification of the developed method were 0.03-0.15 μg/L (S/N=10). The linear range was from 0.20 μg/L to 50.0 μg/L, while the correlation coefficients (R2) were more than 0.998. At the spiked level of 0.200 μg/L, the relative standard deviations of this method were 3.3%-8.9%, the relative recoveries ranged from 86.0% to 103.5%. At higher spiked level, the relative standard deviations were less than 5%, and the relative recoveries ranged from 94.5% to 101.5%.
2017, 45(11): 1719-1726
doi: 10.11895/j.issn.0253-3820.171028
Abstract:
The isotopic fingerprints of plutonium are extremely important for nuclear safeguards and nuclear forensics. An analytical method was developed for direct determination of 240Pu/239Pu ratio in plutonium-containing particles by laser ablation multiple collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The risk of ablated particles leakage was reduced by leak detection, exhaust hood, and swiping the laser cell. Scanning mobility particle sizer (SMPS) was used to measure the effect of ablation parameters on the size distribution of ablated particles. The results showed that the majority of ablation material presented as particles from 40-500 nm and the sweep time after laser ablation should be longer than 15 min. The particle size was evaluated to guide LA-MC-ICP-MS system. By using external normalization method for correction of the mass fractionation correction factor and ion counter efficiencies measured by nebulizer-coupled MC-ICP-MS, a LA-MC-ICP-MS method was established for analysis of 239Pu/240Pu ratio in plutonium particles. Spot size, ablation rate and laser dwell time were set at 30 μm, 5 Hz and 5 s, respectively. Laser energy density was controlled to ensure that the intensities of 239Pu for plutonium-containing particles were about 2×104 cps and 2×105 cps, respectively. The analytical results showed that the relative uncertainties for 239Pu/240Pu was less than 1.4% (n=6), and the measured value deviated by less than 4.7% from the reference value. The time for adjusting system and determining 239Pu/240Pu ratio in single plutonium particle was 9 h and 0.5 h, respectively. The results demonstrated that this technique was rapid, precise and accurate, and could be used for determination of 239Pu/240Pu in plutonium-containing particles.
The isotopic fingerprints of plutonium are extremely important for nuclear safeguards and nuclear forensics. An analytical method was developed for direct determination of 240Pu/239Pu ratio in plutonium-containing particles by laser ablation multiple collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The risk of ablated particles leakage was reduced by leak detection, exhaust hood, and swiping the laser cell. Scanning mobility particle sizer (SMPS) was used to measure the effect of ablation parameters on the size distribution of ablated particles. The results showed that the majority of ablation material presented as particles from 40-500 nm and the sweep time after laser ablation should be longer than 15 min. The particle size was evaluated to guide LA-MC-ICP-MS system. By using external normalization method for correction of the mass fractionation correction factor and ion counter efficiencies measured by nebulizer-coupled MC-ICP-MS, a LA-MC-ICP-MS method was established for analysis of 239Pu/240Pu ratio in plutonium particles. Spot size, ablation rate and laser dwell time were set at 30 μm, 5 Hz and 5 s, respectively. Laser energy density was controlled to ensure that the intensities of 239Pu for plutonium-containing particles were about 2×104 cps and 2×105 cps, respectively. The analytical results showed that the relative uncertainties for 239Pu/240Pu was less than 1.4% (n=6), and the measured value deviated by less than 4.7% from the reference value. The time for adjusting system and determining 239Pu/240Pu ratio in single plutonium particle was 9 h and 0.5 h, respectively. The results demonstrated that this technique was rapid, precise and accurate, and could be used for determination of 239Pu/240Pu in plutonium-containing particles.
2017, 45(11): 1727-1733
doi: 10.11895/j.issn.0253-3820.171120
Abstract:
A method of capillary electrophoresis fingerprint was developed for evaluation of the quality of Arnebia euchroma (Royle) Johnst. The samples were separated on a 50 μm×40 cm uncoated capillary separation column at separation voltage of 25 kV with 100 mmol/L borate buffer (pH 8.0) containing 25 mmol/L SDS and 20% (V/V) dehydrated alcohol as running buffer. The injection volume of sample was 0.5 psi×5 s and the detection wavelength was 214 nm. The results indicated that the samples of Arnebia euchroma (Royle) Johnst were well separated and detected in 35 min. With Shikonin peak as reference peak, 6 characteristic peaks of standard Arnebia euchroma (Royle) Johnst were determined. The quality discriminant analyses were accomplished for different kinds of samples named Arnebia euchroma (Royle) Johnst that purchased from eight sources by means of characteristic fingerprint peak analysis, similarity evaluation and cluster analysis. This method had good reproducibility, and could be used for the quality control of Arnebia euchroma (Royle) Johnst.
A method of capillary electrophoresis fingerprint was developed for evaluation of the quality of Arnebia euchroma (Royle) Johnst. The samples were separated on a 50 μm×40 cm uncoated capillary separation column at separation voltage of 25 kV with 100 mmol/L borate buffer (pH 8.0) containing 25 mmol/L SDS and 20% (V/V) dehydrated alcohol as running buffer. The injection volume of sample was 0.5 psi×5 s and the detection wavelength was 214 nm. The results indicated that the samples of Arnebia euchroma (Royle) Johnst were well separated and detected in 35 min. With Shikonin peak as reference peak, 6 characteristic peaks of standard Arnebia euchroma (Royle) Johnst were determined. The quality discriminant analyses were accomplished for different kinds of samples named Arnebia euchroma (Royle) Johnst that purchased from eight sources by means of characteristic fingerprint peak analysis, similarity evaluation and cluster analysis. This method had good reproducibility, and could be used for the quality control of Arnebia euchroma (Royle) Johnst.
2017, 45(11): 1734-1744
doi: 10.11895/j.issn.0253-3820.170259
Abstract:
Chemotaxis is the response ability of motile cells to chemicals gradients in environment and the migration toward higher concentration of chemoattractant or lower concentration of repellent. This mechanism is a basic nature of microorganisms to adapt to the environmental changes. The research of microbial chemotaxis is of great significance in utilizing bacteria to solve environment problems, control the pathogen infection, and develop microbial industrial projects. Microfluidic devices can realize qualitatively and quantitatively detect of bacterial chemotaxis. In comparison with traditional detect methods, microfluidic assay has an accurate control over bacterial microenvironment, with a higher sensitivity. In the past few years, bacterial chemotaxis study based on microfluidic assay was developed rapidly. In this paper, the microfluidic chemotaxis detectors that appeared in recent years were introduced from the aspect of chip structure, working principle and their applications. Finally, we provided insights into the challenges of bacterial chemotaxis and provided future perspectives.
Chemotaxis is the response ability of motile cells to chemicals gradients in environment and the migration toward higher concentration of chemoattractant or lower concentration of repellent. This mechanism is a basic nature of microorganisms to adapt to the environmental changes. The research of microbial chemotaxis is of great significance in utilizing bacteria to solve environment problems, control the pathogen infection, and develop microbial industrial projects. Microfluidic devices can realize qualitatively and quantitatively detect of bacterial chemotaxis. In comparison with traditional detect methods, microfluidic assay has an accurate control over bacterial microenvironment, with a higher sensitivity. In the past few years, bacterial chemotaxis study based on microfluidic assay was developed rapidly. In this paper, the microfluidic chemotaxis detectors that appeared in recent years were introduced from the aspect of chip structure, working principle and their applications. Finally, we provided insights into the challenges of bacterial chemotaxis and provided future perspectives.
2017, 45(11): 1745-1753
doi: 10.11895/j.issn.0253-3820.170097
Abstract:
Polymerase chain reaction (PCR) has become one of the powerful technique since its invention in 1980s. Nevertheless, PCR technique is still frequently impaired by its low specificity, poor sensitivity, false positive results, etc. Recently, nanomaterials including metal nanoparticles, carbon nanomaterials, quantum dots and nano metal oxide have been added into PCR solution to improve both quality and productivity of PCR. The nanoparticles assisted PCR (NanoPCR) has received considerable attentions due to its unprecedented sensitivity, selectivity and efficiency. In this view, the mainly used nanoparticles in NanoPCR, including gold nanoparticles, quantum dots, carbon nanomaterials, graphene and metallic oxide, was firstly summarized. And then, the possible mechanisms for highly improved sensitivity and selectivity were discussed. Finally, recent applications of NanoPCR were described.
Polymerase chain reaction (PCR) has become one of the powerful technique since its invention in 1980s. Nevertheless, PCR technique is still frequently impaired by its low specificity, poor sensitivity, false positive results, etc. Recently, nanomaterials including metal nanoparticles, carbon nanomaterials, quantum dots and nano metal oxide have been added into PCR solution to improve both quality and productivity of PCR. The nanoparticles assisted PCR (NanoPCR) has received considerable attentions due to its unprecedented sensitivity, selectivity and efficiency. In this view, the mainly used nanoparticles in NanoPCR, including gold nanoparticles, quantum dots, carbon nanomaterials, graphene and metallic oxide, was firstly summarized. And then, the possible mechanisms for highly improved sensitivity and selectivity were discussed. Finally, recent applications of NanoPCR were described.
