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2016 Volume 44 Issue 9
2016, 44(9): 1315-1321
doi: 10.11895/j.issn.0253-3820.160166
Abstract:
A SnO2-CuO composite nanofiber was prepared by the coaxial electrospinning method. A new thin-film-type hydrogen sulfide gas sensor was designed by coating SnO2-CuO composite nanofibers onto an alumina ceramic tube with Au electrodes by dip-coating method. The crystalline phase and microstructure of SnO2-CuO composite nanofibers were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The influence of chemical composition and thickness of sensitive film on the sensitive mechanism and electrochemical characteristic of SnO2-CuO nanofibers were analyzed. The characteristic tests of hydrogen sulfide sensor including sensitive performance, temperature, relative humidity, dynamic response, interference and stability were carried out by WS-30A type multifunction analyzer in gas sensor test system. The results demonstrated that, when the operating temperature was 25℃ and hydrogen sulfide gas concentration increased from 10 to 60 mg/L, the hydrogen sulfide sensor based on C50 composite nanofibers with 70 nm sensitive film thickness had the best linearity (92.3%) and sensitivity (98.2%). Besides, its highest response values and relatively humidity level were 1080 and 95%, respectively, and its dynamic response time and recover time were 4 s and 12 s, respectively. This sensor showed good anti-disturbance to the gases, such as CO, NO2, SO2, NH3, CO2, CH4 and H2. The response value of the sensor was attenuated about 9.2% when it was applied continually in the mine about 12 months, and its normal response time was 10.9 months.
A SnO2-CuO composite nanofiber was prepared by the coaxial electrospinning method. A new thin-film-type hydrogen sulfide gas sensor was designed by coating SnO2-CuO composite nanofibers onto an alumina ceramic tube with Au electrodes by dip-coating method. The crystalline phase and microstructure of SnO2-CuO composite nanofibers were characterized using X-ray diffraction (XRD) and scanning electron microscope (SEM). The influence of chemical composition and thickness of sensitive film on the sensitive mechanism and electrochemical characteristic of SnO2-CuO nanofibers were analyzed. The characteristic tests of hydrogen sulfide sensor including sensitive performance, temperature, relative humidity, dynamic response, interference and stability were carried out by WS-30A type multifunction analyzer in gas sensor test system. The results demonstrated that, when the operating temperature was 25℃ and hydrogen sulfide gas concentration increased from 10 to 60 mg/L, the hydrogen sulfide sensor based on C50 composite nanofibers with 70 nm sensitive film thickness had the best linearity (92.3%) and sensitivity (98.2%). Besides, its highest response values and relatively humidity level were 1080 and 95%, respectively, and its dynamic response time and recover time were 4 s and 12 s, respectively. This sensor showed good anti-disturbance to the gases, such as CO, NO2, SO2, NH3, CO2, CH4 and H2. The response value of the sensor was attenuated about 9.2% when it was applied continually in the mine about 12 months, and its normal response time was 10.9 months.
2016, 44(9): 1322-1327
doi: 10.11895/j.issn.0253-3820.160292
Abstract:
Lysozyme, pepsin, ovalbumin, hemoglobin and γ-globumin were chosen as templates to investigate the imprinting capability of amphoteric polyacrylamide cryogels. Prepolymerizing solutions contained acrylic acid and allyl amine, as well as acrylamide and N,N'-methylenebisacrylamide as the functional monomers. As a result there were both acidic and basic functional groups in the polymers, facilitating effective interactions with likewise amphoteric proteins. The proteins differ greatly and cover wide scopes of molecular weights and isoelectric points. Regardless of the values of the molecular weights and isoelectric points, all the templates gave higher retentions on the MIP tubes than on the NIP tube. The MIP of lysozyme indicated the highest imprinting factor of 7.0, and that of γ-globumin showed the lowest, 2.0. The values of other proteins were intervenient. Conclusively the amphoteric polyacrylamide cryogels were suitable imprinting materials for various proteins, and could potentially be used for protein recognition, purification, and depletion.
Lysozyme, pepsin, ovalbumin, hemoglobin and γ-globumin were chosen as templates to investigate the imprinting capability of amphoteric polyacrylamide cryogels. Prepolymerizing solutions contained acrylic acid and allyl amine, as well as acrylamide and N,N'-methylenebisacrylamide as the functional monomers. As a result there were both acidic and basic functional groups in the polymers, facilitating effective interactions with likewise amphoteric proteins. The proteins differ greatly and cover wide scopes of molecular weights and isoelectric points. Regardless of the values of the molecular weights and isoelectric points, all the templates gave higher retentions on the MIP tubes than on the NIP tube. The MIP of lysozyme indicated the highest imprinting factor of 7.0, and that of γ-globumin showed the lowest, 2.0. The values of other proteins were intervenient. Conclusively the amphoteric polyacrylamide cryogels were suitable imprinting materials for various proteins, and could potentially be used for protein recognition, purification, and depletion.
2016, 44(9): 1328-1334
doi: 10.11895/j.issn.0253-3820.160162
Abstract:
A cadmium column reduction-azo dyes spectrophotometric method based on micro sequential injection lab-on-valve was established for the determination of total nitrogen in seawater. The experimental parameters were optimized, and the interference experiment was carried out. The results showed that the interference of the main components and salinity in sea water could be eliminated by using a series of standard solution prepared by national standard seawater with certain salinity. The concentration of total nitrogen in seawater was linear with the absorbance in the range of 0.03-1.00 mg/L with a correlation coefficient of 0.9993. When determining the national standard seawater at nitrogen concentration of 0.20 mg/L, the relative standard deviation (RSD) was 4.9%, the detection limit was 0.010 mg/L, and the recoveries were 99.5%-101.1%. There were not significance differences between the results of this method and national standard method in the t-test analysis. The method is suitable for the determination of total nitrogen in seawater.
A cadmium column reduction-azo dyes spectrophotometric method based on micro sequential injection lab-on-valve was established for the determination of total nitrogen in seawater. The experimental parameters were optimized, and the interference experiment was carried out. The results showed that the interference of the main components and salinity in sea water could be eliminated by using a series of standard solution prepared by national standard seawater with certain salinity. The concentration of total nitrogen in seawater was linear with the absorbance in the range of 0.03-1.00 mg/L with a correlation coefficient of 0.9993. When determining the national standard seawater at nitrogen concentration of 0.20 mg/L, the relative standard deviation (RSD) was 4.9%, the detection limit was 0.010 mg/L, and the recoveries were 99.5%-101.1%. There were not significance differences between the results of this method and national standard method in the t-test analysis. The method is suitable for the determination of total nitrogen in seawater.
2016, 44(9): 1335-1341
doi: 10.11895/j.issn.0253-3820.160180
Abstract:
Experiments were conducted to investigate the suitability of the multistage in-situ reaction analyzer based on a micro fluidized bed (MFB-MIRA) for measuring the rapid change of the gas concentration during gas-solid reactions. The results showed that the control performance of capillary temperature had a great impact on the stability of on-line measurement. Based on the observed regular patterns, the capillary temperature control system was equipped with a precision temperature controller. The control precision of capillary temperature reached ±0.2℃, which guaranteed the high stabilities of the sampling flow rate and the chamber vacuum. The measured results of the modified gas monitoring system showed the periodic fluctuations of the on-line measurement were eliminated. The stability of measurement was significantly improved. The fluctuating range and relative standard deviation of the measured response to O2 in air changed from 1.9% and 0.5% to 1.4% and 0.2%, respectively. A pressure regulating device was also developed to control the absolute pressure at the gas sampling point. The control precision reached ± 0.02 kPa. The measured results showed that the response of the process mass spectrometer was positively correlated with the absolute pressure at the sampling point, indicating the necessity of the pressure regulating device. The accuracy and repeatability of process mass spectrometer were improved. This study has enhanced the suitability of MFB-MIRA for studying rapid gas-solid reactions and broadened the scope of reliable applications of MFB-MIRA and process mass spectrometer.
Experiments were conducted to investigate the suitability of the multistage in-situ reaction analyzer based on a micro fluidized bed (MFB-MIRA) for measuring the rapid change of the gas concentration during gas-solid reactions. The results showed that the control performance of capillary temperature had a great impact on the stability of on-line measurement. Based on the observed regular patterns, the capillary temperature control system was equipped with a precision temperature controller. The control precision of capillary temperature reached ±0.2℃, which guaranteed the high stabilities of the sampling flow rate and the chamber vacuum. The measured results of the modified gas monitoring system showed the periodic fluctuations of the on-line measurement were eliminated. The stability of measurement was significantly improved. The fluctuating range and relative standard deviation of the measured response to O2 in air changed from 1.9% and 0.5% to 1.4% and 0.2%, respectively. A pressure regulating device was also developed to control the absolute pressure at the gas sampling point. The control precision reached ± 0.02 kPa. The measured results showed that the response of the process mass spectrometer was positively correlated with the absolute pressure at the sampling point, indicating the necessity of the pressure regulating device. The accuracy and repeatability of process mass spectrometer were improved. This study has enhanced the suitability of MFB-MIRA for studying rapid gas-solid reactions and broadened the scope of reliable applications of MFB-MIRA and process mass spectrometer.
2016, 44(9): 1342-1347
doi: 10.11895/j.issn.0253-3820.160153
Abstract:
The δ13C values of volatile organic compounds (VOCs) in various emission sources and ambient air were analyzed by using thermal desorption coupled with gas chromatography and isotope ratio mass. The lowest sample concentration and peak shape quality needed for high precision and accurate analysis were investigated. Fuel evaporation (gasoline and diesel), vehicle exhaust, solvent evaporation, dining fumes and ambient air of different functional zones of Xiamen city were collected using Tenax TA tube, and the significant differences in δ13C values of VOCs between these sources were observed. The δ13C value of gasoline exhaust (97#) was heavier (-25.84‰) than that of dining fumes (-30.26‰) and the δ13C values of fuel evaporation were heavier than that of vehicle exhaust after combustion. The average δ13C value of atmospheric VOCs in Xiamen was at the level of -27.03‰ to -25.40‰, which was close to the δ13C value of the evaporation and exhaust of gasoline and diesel, indicating that the VOCs in the atmosphere of Xiamen was highly influenced by transportation related sources.
The δ13C values of volatile organic compounds (VOCs) in various emission sources and ambient air were analyzed by using thermal desorption coupled with gas chromatography and isotope ratio mass. The lowest sample concentration and peak shape quality needed for high precision and accurate analysis were investigated. Fuel evaporation (gasoline and diesel), vehicle exhaust, solvent evaporation, dining fumes and ambient air of different functional zones of Xiamen city were collected using Tenax TA tube, and the significant differences in δ13C values of VOCs between these sources were observed. The δ13C value of gasoline exhaust (97#) was heavier (-25.84‰) than that of dining fumes (-30.26‰) and the δ13C values of fuel evaporation were heavier than that of vehicle exhaust after combustion. The average δ13C value of atmospheric VOCs in Xiamen was at the level of -27.03‰ to -25.40‰, which was close to the δ13C value of the evaporation and exhaust of gasoline and diesel, indicating that the VOCs in the atmosphere of Xiamen was highly influenced by transportation related sources.
2016, 44(9): 1348-1353
doi: 10.11895/j.issn.0253-3820.160128
Abstract:
A new method for chiral separation and purity inspection of landiolol hydrochloride and its stereoisomers was developed by ultra-performance convergence chromatography (UPC2). The mobile phase was the mixture of supercritical CO2 and methanol/n-butyl alcohol/acetonitrile (1:1:1, V/V) plus 0.5% NH3·H2O. The separation was carried out on the Daicel CHIRALPAK®IF column (150 mm×4.6 mm, 3 μm) with a flow rate of 2.8 mL/min at 50℃ using 223 nm as detection wavelength. Under the optimized experimental conditions, for R,R-stereoisomer, R,S-stereoisomer and S,R-stereoisomer, the detection limits (LOD, S/N=3) were 0.3, 0.4 and 0.3 mg/L, the linear ranges were 2-300 mg/L, 5-300 mg/L and 2-300 mg/L, the recoveries of spike samples were 103.4%±2.5%, 91.8%±2.5% and 101.7%±1.5%, and the injection repeatabilities were 0.06%, 0.09% and 0.08% (n=6), respectively. The experimental results demonstrate that the UPC2-based method can be used for the analysis and determination of landiolol hydrochloride and its stereoisomers.
A new method for chiral separation and purity inspection of landiolol hydrochloride and its stereoisomers was developed by ultra-performance convergence chromatography (UPC2). The mobile phase was the mixture of supercritical CO2 and methanol/n-butyl alcohol/acetonitrile (1:1:1, V/V) plus 0.5% NH3·H2O. The separation was carried out on the Daicel CHIRALPAK®IF column (150 mm×4.6 mm, 3 μm) with a flow rate of 2.8 mL/min at 50℃ using 223 nm as detection wavelength. Under the optimized experimental conditions, for R,R-stereoisomer, R,S-stereoisomer and S,R-stereoisomer, the detection limits (LOD, S/N=3) were 0.3, 0.4 and 0.3 mg/L, the linear ranges were 2-300 mg/L, 5-300 mg/L and 2-300 mg/L, the recoveries of spike samples were 103.4%±2.5%, 91.8%±2.5% and 101.7%±1.5%, and the injection repeatabilities were 0.06%, 0.09% and 0.08% (n=6), respectively. The experimental results demonstrate that the UPC2-based method can be used for the analysis and determination of landiolol hydrochloride and its stereoisomers.
2016, 44(9): 1354-1358
doi: 10.11895/j.issn.0253-3820.160245
Abstract:
A novel method based on methylene blue (MB) was established for the rapid determination of acute water toxicity with the P. fluorescens as the test organism and the damage of cell membrane as the toxicity response. In this method, the damaged rather than intact cells could be stained positively by MB. Therefore, in the presence of toxicants that could induce the damage of cell membrane, MB would enter into cells, resulting in a decrease in MB concentration of the solution. The acute water toxicity could thus be determined by measuring the changes optically in the concentration of MB in the solutions. The present results displayed that, the detection limits of the reported method for 3,5-dichlorophenol, As3+ and Hg2+ were 1.6, 12.5 and 3.2 mg/L, respectively. In special, the detection limit of the reported method for 3,5-dichlorophenol (DCP) was lower than that of the commercial equipment, Baroxymeter. The reported method is simple, rapid and reliable, and shows an excellent promise in the determination and monitoring of acute toxicity.
A novel method based on methylene blue (MB) was established for the rapid determination of acute water toxicity with the P. fluorescens as the test organism and the damage of cell membrane as the toxicity response. In this method, the damaged rather than intact cells could be stained positively by MB. Therefore, in the presence of toxicants that could induce the damage of cell membrane, MB would enter into cells, resulting in a decrease in MB concentration of the solution. The acute water toxicity could thus be determined by measuring the changes optically in the concentration of MB in the solutions. The present results displayed that, the detection limits of the reported method for 3,5-dichlorophenol, As3+ and Hg2+ were 1.6, 12.5 and 3.2 mg/L, respectively. In special, the detection limit of the reported method for 3,5-dichlorophenol (DCP) was lower than that of the commercial equipment, Baroxymeter. The reported method is simple, rapid and reliable, and shows an excellent promise in the determination and monitoring of acute toxicity.
2016, 44(9): 1359-1364
doi: 10.11895/j.issn.0253-3820.160348
Abstract:
A new method for accurate determination of 15 rare earth elements including Y-Lu in tea samples by inductively coupled plasma-mass spectrometry(ICP-MS) was proposed. Sample preparation was based on the modified oxygen flask combustion technique. By using quartz cloth coated with glycerol instead of filter paper as the ignition agent, a total amount of 0.1 g sample could be completely burned in a 500-mL flask. Key factors affecting the sample preparation effect were systematically investigated, and it was found that the extraction efficiencies of over 90% for all the analytes could be realized with 5 mL of 4% HNO3 +1% HF (V/V) as the extractant for the combustion residue and the total extraction process could be finished in one minute under sonication, which resulted in a very fast sample preparation procedure that could be completed in less than 3 minutes. The relative standard deviations (RSD) of six parallel determination values were between 2.7% and 5.5%, and the detection limits ranged from 0.001 mg/kg to 0.006 mg/kg. Three tea standard reference materials were analyzed with the method and the detection results agreed well with the standard values. The method was successfully applied to three real samples analysis.
A new method for accurate determination of 15 rare earth elements including Y-Lu in tea samples by inductively coupled plasma-mass spectrometry(ICP-MS) was proposed. Sample preparation was based on the modified oxygen flask combustion technique. By using quartz cloth coated with glycerol instead of filter paper as the ignition agent, a total amount of 0.1 g sample could be completely burned in a 500-mL flask. Key factors affecting the sample preparation effect were systematically investigated, and it was found that the extraction efficiencies of over 90% for all the analytes could be realized with 5 mL of 4% HNO3 +1% HF (V/V) as the extractant for the combustion residue and the total extraction process could be finished in one minute under sonication, which resulted in a very fast sample preparation procedure that could be completed in less than 3 minutes. The relative standard deviations (RSD) of six parallel determination values were between 2.7% and 5.5%, and the detection limits ranged from 0.001 mg/kg to 0.006 mg/kg. Three tea standard reference materials were analyzed with the method and the detection results agreed well with the standard values. The method was successfully applied to three real samples analysis.
2016, 44(9): 1365-1371
doi: 10.11895/j.issn.0253-3820.160277
Abstract:
Aliphatic amines in infant food packaging materials were extracted and concentrated by 0.5 mL of acidified methanol using gas purge microsyringe extraction (GP-MSE). Pre-column fluorescence labeling of amines was achieved in mild conditions with 10-ethyl-acridine-2-sulfonyl chloride (EASC) as labeling reagent. The derivatization was carried out at 60℃ and pH 10. The derivatives were successfully separated on a Hypersil GOLD column with excitation and emission wavelengths of 262 and 430 nm, respectively. The detection limits were in the range of 0.4-0.6 μg/kg, and the quantitation limits were in the range of 1.2-2.1 μg/kg. All analytes were in good linearity in the concentration range of 2.0-2000 μg/L with correlation coefficients of higher than 0.998. The developed method was characterized by celerity, accuracy and high sensitivity. It was successfully applied to the determination of aliphatic amines in infant food packaging materials.
Aliphatic amines in infant food packaging materials were extracted and concentrated by 0.5 mL of acidified methanol using gas purge microsyringe extraction (GP-MSE). Pre-column fluorescence labeling of amines was achieved in mild conditions with 10-ethyl-acridine-2-sulfonyl chloride (EASC) as labeling reagent. The derivatization was carried out at 60℃ and pH 10. The derivatives were successfully separated on a Hypersil GOLD column with excitation and emission wavelengths of 262 and 430 nm, respectively. The detection limits were in the range of 0.4-0.6 μg/kg, and the quantitation limits were in the range of 1.2-2.1 μg/kg. All analytes were in good linearity in the concentration range of 2.0-2000 μg/L with correlation coefficients of higher than 0.998. The developed method was characterized by celerity, accuracy and high sensitivity. It was successfully applied to the determination of aliphatic amines in infant food packaging materials.
2016, 44(9): 1372-1377
doi: 10.11895/j.issn.0253-3820.160080
Abstract:
To investigate the mechanism of lead biosorption and biotransformation in lead-resistant bacteria in microcosmic scale, synchrotron radiation micro X-ray fluorescence (μ-SRXRF) and X-ray absorption near edge structure (XANES) was used to determine the element distribution characteristics and speciation of lead(Pb) in lead-resistant bacteria strain isolated from farmland soil samples taken from a lead-zinc mine in Lanping county, Yunnan province in China. The isolated species was identified to be Arthrobacter sp. The concentration of Pb biosorpted in lead-resistant bacteria was directly determined by μ-SRXRF, and the results showed that the highest concentration was 5925 μg/g and the bioaccumulate factor was 14.8. Speciation of Pb in lead-resistant bacteria B2, LB (Lysogeny Broth) medium and soil were also presented after using Pb LⅢ XANES. Compared with Pb LⅢ XANES peak shape and peak position between standard samples, it was demonstrated that the Pb in lead-resistant bacteria was mainly formed by amorphous forms like PbS (58.0%), (C17H35COO)2Pb (22.2%), Pb5(PO4)3Cl (19.8%) rather than organic Pb speciation which was exist in LB medium. Therefore, the isolated lead-resistant bacteria could biotransform Pb to sulfuric compounds. The biotransformation regular could be of great interest for other investigators as reference in study of bioavailability impact factor of heavy metals.
To investigate the mechanism of lead biosorption and biotransformation in lead-resistant bacteria in microcosmic scale, synchrotron radiation micro X-ray fluorescence (μ-SRXRF) and X-ray absorption near edge structure (XANES) was used to determine the element distribution characteristics and speciation of lead(Pb) in lead-resistant bacteria strain isolated from farmland soil samples taken from a lead-zinc mine in Lanping county, Yunnan province in China. The isolated species was identified to be Arthrobacter sp. The concentration of Pb biosorpted in lead-resistant bacteria was directly determined by μ-SRXRF, and the results showed that the highest concentration was 5925 μg/g and the bioaccumulate factor was 14.8. Speciation of Pb in lead-resistant bacteria B2, LB (Lysogeny Broth) medium and soil were also presented after using Pb LⅢ XANES. Compared with Pb LⅢ XANES peak shape and peak position between standard samples, it was demonstrated that the Pb in lead-resistant bacteria was mainly formed by amorphous forms like PbS (58.0%), (C17H35COO)2Pb (22.2%), Pb5(PO4)3Cl (19.8%) rather than organic Pb speciation which was exist in LB medium. Therefore, the isolated lead-resistant bacteria could biotransform Pb to sulfuric compounds. The biotransformation regular could be of great interest for other investigators as reference in study of bioavailability impact factor of heavy metals.
2016, 44(9): 1378-1384
doi: 10.11895/j.issn.0253-3820.160126
Abstract:
The core-shell nanopaticles of Au@polyvinyl-pyrrolidone (PVP) with uniform size and controllabe shell-thickness were prepared by hydrothermal method. The core-shell nanoparticles could be assembled to be the monolayer array on Si substrate relying on the dispersion of core-shell nanoparticles arising from PVP shell. The malachite green (MG) absorbed by H-bond could be detected on the array under the electromagnetic enhancement of inner-core Au nanoparticles. Under the conditions of the optimum shell-thickness of Au@PVP and the appropriate absorbed time of MG, the detection of MG could be realized in the linear range from 1×10-10 mol/L to 1×10-5 mol/L with the correlation coefficient (R2) of 0.98. The detection limit was 10-12 mol/L. This method was applied to the determination of MG in tilapia fish fillets of Xiagang market. No MG was found in this real sample. The spiked recoveries of the sample ranged from 70.8% to 126.0%.This method is simple and accurate, and can be used for detection of MG in the fish.
The core-shell nanopaticles of Au@polyvinyl-pyrrolidone (PVP) with uniform size and controllabe shell-thickness were prepared by hydrothermal method. The core-shell nanoparticles could be assembled to be the monolayer array on Si substrate relying on the dispersion of core-shell nanoparticles arising from PVP shell. The malachite green (MG) absorbed by H-bond could be detected on the array under the electromagnetic enhancement of inner-core Au nanoparticles. Under the conditions of the optimum shell-thickness of Au@PVP and the appropriate absorbed time of MG, the detection of MG could be realized in the linear range from 1×10-10 mol/L to 1×10-5 mol/L with the correlation coefficient (R2) of 0.98. The detection limit was 10-12 mol/L. This method was applied to the determination of MG in tilapia fish fillets of Xiagang market. No MG was found in this real sample. The spiked recoveries of the sample ranged from 70.8% to 126.0%.This method is simple and accurate, and can be used for detection of MG in the fish.
2016, 44(9): 1385-1393
doi: 10.11895/j.issn.0253-3820.160360
Abstract:
To produce specific antibodies against malachite green (MG), one special hapten was synthesized and characterized, and conjugated to carrier protein as immunogen. The immunogen showed excellent reactogenicity and immunogenicity. One specific monoclonal antibody (mAb, named MG-DA4-C7) with high sensitivity and specificity for MG in indirect competitive enzyme-linked immunoassay (icELISA) was screened. The isotype was IgG1 and the light chain was κ type. After optimization of ELISA conditions, the proposed icELISA showed a 50% inhibition value (IC50) of 0.96 μg/L, a linear range (IC20-IC80) of 0.1-8.1 μg/L and a limit of detection (LOD, IC10) of 0.05 μg/L for determination of MG. The assay showed cross-reactivity of 18.1%, 26.5% with crystal violet and brilliant green, respectively, and negligible cross-reactivity with other metabolites of MG (<0.1%). The average recoveries of MG from spiked fish samples were from 87.3% to 107.3%. Good correlation (R2=0.999) was obtained between the results of icELISA and those of liquid chromatography-tandem mass spectrometry analysis. The proposed icELISA is suitable for the determination of MG in fish samples in a simple and sensitive manner.
To produce specific antibodies against malachite green (MG), one special hapten was synthesized and characterized, and conjugated to carrier protein as immunogen. The immunogen showed excellent reactogenicity and immunogenicity. One specific monoclonal antibody (mAb, named MG-DA4-C7) with high sensitivity and specificity for MG in indirect competitive enzyme-linked immunoassay (icELISA) was screened. The isotype was IgG1 and the light chain was κ type. After optimization of ELISA conditions, the proposed icELISA showed a 50% inhibition value (IC50) of 0.96 μg/L, a linear range (IC20-IC80) of 0.1-8.1 μg/L and a limit of detection (LOD, IC10) of 0.05 μg/L for determination of MG. The assay showed cross-reactivity of 18.1%, 26.5% with crystal violet and brilliant green, respectively, and negligible cross-reactivity with other metabolites of MG (<0.1%). The average recoveries of MG from spiked fish samples were from 87.3% to 107.3%. Good correlation (R2=0.999) was obtained between the results of icELISA and those of liquid chromatography-tandem mass spectrometry analysis. The proposed icELISA is suitable for the determination of MG in fish samples in a simple and sensitive manner.
2016, 44(9): 1394-1401
doi: 10.11895/j.issn.0253-3820.160220
Abstract:
An ordered mesoporous silica (OMS) was synthesized through hydrothermal process. The synthesized material was characterized by different techniques such as X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscope. The electrochemical characteristics of the OMS modified carbon paste electrode (OMS/CPE) were investigated by using cyclic voltammetry and electrochemical impedance spectroscopy. Compared with bare carbon paste electrode (CPE), the OMS/CPE exhibited a larger electrode surface and a faster electron-transfer rate. Electrochemical behaviors and kinetic properties of L-tryptophan (L-Trp) at the OMS/CPE in the presence of sodium dodecylsulphate (SDS) were studied. The results showed that the voltammetric response of L-Trp at OMS/CPE was improved due to the synergistic effect of OMS and SDS. The electrochemical oxidation of L-Trp at OMS/CPE in the presence of SDS was an irreversible process involved two electrons and two protons, and the electrode process was controlled by the adsorption step. Some parameters such as SDS concentration, accumulation time, accumulation potential and pH were optimized. Under optimal conditions, the oxidation peak current was linearly proportional to L-Trp concentration in the range of 8.0×10-8 to 4.0×10-6 mol/L, with a detection limit of 7.0×10-8 mol/L (S/N=3). The proposed method was applied for the determination of L-Trp in oral liquid with the recoveries of 99.6%-102.6%.
An ordered mesoporous silica (OMS) was synthesized through hydrothermal process. The synthesized material was characterized by different techniques such as X-ray diffraction, nitrogen adsorption-desorption and transmission electron microscope. The electrochemical characteristics of the OMS modified carbon paste electrode (OMS/CPE) were investigated by using cyclic voltammetry and electrochemical impedance spectroscopy. Compared with bare carbon paste electrode (CPE), the OMS/CPE exhibited a larger electrode surface and a faster electron-transfer rate. Electrochemical behaviors and kinetic properties of L-tryptophan (L-Trp) at the OMS/CPE in the presence of sodium dodecylsulphate (SDS) were studied. The results showed that the voltammetric response of L-Trp at OMS/CPE was improved due to the synergistic effect of OMS and SDS. The electrochemical oxidation of L-Trp at OMS/CPE in the presence of SDS was an irreversible process involved two electrons and two protons, and the electrode process was controlled by the adsorption step. Some parameters such as SDS concentration, accumulation time, accumulation potential and pH were optimized. Under optimal conditions, the oxidation peak current was linearly proportional to L-Trp concentration in the range of 8.0×10-8 to 4.0×10-6 mol/L, with a detection limit of 7.0×10-8 mol/L (S/N=3). The proposed method was applied for the determination of L-Trp in oral liquid with the recoveries of 99.6%-102.6%.
2016, 44(9): 1402-1409
doi: 10.11895/j.issn.0253-3820.160170
Abstract:
The fourth generation poly(amidoamine) dendrimers (G4.0 PAMAM) functionalized multiwalled carbon nanotube (G4.0-MWCNTs) was prepared by amidation between carboxylated multiwalled carbon nanotube (MWCNTs) and G4.0 PAMAM. Then a novel hydrogen peroxide (H2O2) sensor was fabricated by electrodepositing Pd nanoparticles (NPs) on a glassy carbon electrode (GCE) modified with G4.0-MWCNTs composites. The modified electrode was characterized by field emission scanning electron microscopy (FESEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A large amounts of highly dispersion PdNPs could be well loaded on the surface of the G4.0-MWCNTs, and the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H2O2. Under the optimized conditions, the reduction peak currents of H2O2 were linear to their concentrations in the range from 1.0×10-9 mol/L to 1.0×10-3 mol/L and the limit of detection of 2.3×10-8 mol/L was obtained. The recovery of standard addition for human serum samples was 96.7%-103.1%.
The fourth generation poly(amidoamine) dendrimers (G4.0 PAMAM) functionalized multiwalled carbon nanotube (G4.0-MWCNTs) was prepared by amidation between carboxylated multiwalled carbon nanotube (MWCNTs) and G4.0 PAMAM. Then a novel hydrogen peroxide (H2O2) sensor was fabricated by electrodepositing Pd nanoparticles (NPs) on a glassy carbon electrode (GCE) modified with G4.0-MWCNTs composites. The modified electrode was characterized by field emission scanning electron microscopy (FESEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). A large amounts of highly dispersion PdNPs could be well loaded on the surface of the G4.0-MWCNTs, and the modified electrode exhibited excellent electrocatalytic activity towards the reduction of H2O2. Under the optimized conditions, the reduction peak currents of H2O2 were linear to their concentrations in the range from 1.0×10-9 mol/L to 1.0×10-3 mol/L and the limit of detection of 2.3×10-8 mol/L was obtained. The recovery of standard addition for human serum samples was 96.7%-103.1%.
2016, 44(9): 1410-1418
doi: 10.11895/j.issn.0253-3820.160113
Abstract:
A rapid resolution liquid chromatography quadruple time-of-flight mass spectrometric (RRLC-Q-TOF/MS) method combined with multivariate statistical analysis was applied to investigate the changes of endogenous metabolites in murine urine before and after ultraviolet B(UVB)irradiation for the purpose of discussing the physiological mechanism of acute injury caused by UVB radiation. A narrow-band UVB (NB-UVB) (TL-01, peak value 312nm) was used to establish the acute light damage model. The urine samples were centrifuged before four times dilution treatment, subsequently the diluted urine samples were separated on a Supelco Ascentis Express C18 column using water (0.1% formic acid) and acetonitrile as mobile phase by gradient elution. The differences metabolites with major contribution for grouping were found out based on the metabolic profiling analysis of principal component analysis (PCA) and cluster analysis (CA), which could illustrate their possible mechanism of actions by means of relevant pathways. A prediction model was built to investigate the forecasting ability of the acute photo damage induced by UVB irradiation through the partial least square discriminant analysis (PLS-DA). The results of multivariate statistical analysis showed that the blank control group was separated from UVB model group quite well, 11 endogenous metabolites were identified as the potential biomarkers through comparison with the database, tandem mass spectrum data and standard substance, which indicated the UVB radiation may affect the sphingolipid metabolism, nucleic acid metabolism, linoleic acid metabolism and amino acid metabolism pathways. These different metabolites could be helpful for diagnosing the light damage induced by UVB radiation
A rapid resolution liquid chromatography quadruple time-of-flight mass spectrometric (RRLC-Q-TOF/MS) method combined with multivariate statistical analysis was applied to investigate the changes of endogenous metabolites in murine urine before and after ultraviolet B(UVB)irradiation for the purpose of discussing the physiological mechanism of acute injury caused by UVB radiation. A narrow-band UVB (NB-UVB) (TL-01, peak value 312nm) was used to establish the acute light damage model. The urine samples were centrifuged before four times dilution treatment, subsequently the diluted urine samples were separated on a Supelco Ascentis Express C18 column using water (0.1% formic acid) and acetonitrile as mobile phase by gradient elution. The differences metabolites with major contribution for grouping were found out based on the metabolic profiling analysis of principal component analysis (PCA) and cluster analysis (CA), which could illustrate their possible mechanism of actions by means of relevant pathways. A prediction model was built to investigate the forecasting ability of the acute photo damage induced by UVB irradiation through the partial least square discriminant analysis (PLS-DA). The results of multivariate statistical analysis showed that the blank control group was separated from UVB model group quite well, 11 endogenous metabolites were identified as the potential biomarkers through comparison with the database, tandem mass spectrum data and standard substance, which indicated the UVB radiation may affect the sphingolipid metabolism, nucleic acid metabolism, linoleic acid metabolism and amino acid metabolism pathways. These different metabolites could be helpful for diagnosing the light damage induced by UVB radiation
2016, 44(9): 1419-1424
doi: 10.11895/j.issn.0253-3820.160138
Abstract:
An alternative method based on an off-line solid phase extraction (SPE) combined with programmable temperature vaporizer-based (PTV) large volume injection-gas chromatography-flame ionization detection (LVI-GC-FID) was developed. The goal of this study was to determine mineral oil saturated hydrocarbons (MOSH) in camellia seed oils. The purification condition of SPE columns with silver impregnated the activated silica gel and activated aluminum oxide was optimized. The optimal SPE cartridge was loaded with 10 g of Ag-activated silica gel per 10 g of activated aluminum oxide. The PTV initial temperature was set at 75℃ for 1 min (split 200:1), and heated from 75℃ to 370℃ at 250℃/min. Then the diverter valve was closed for 1 min and opened again with the split flow ratio changing to 50:1. The injection volume was 40 μL. The calibration curve of paraffin oil was liner in the range of 5-500 mg/kg with correlation coefficient of 0.998. The detection limit (LOD) and the quantification limit (LOQ) of paraffin oils in hexane were 0.26 mg/kg and 0.80 mg/kg, respectively. The recoveries from spiked oil samples were between 93.3% and 112.7%, with relative standard deviation (RSD) of 1.8%-5.2%, the RSD of intra-day and inter-day were less than 2.6% . This procedure was applied to analyze the MOSH in 11 commercial camellia seed oils and the contamination was found to range from 6.8 mg/kg to 76.7 mg/kg. The method is simple in operation with high sensitivity, good reproducibility and low cost, and suitable for determination of MOSH in vegetable oils.
An alternative method based on an off-line solid phase extraction (SPE) combined with programmable temperature vaporizer-based (PTV) large volume injection-gas chromatography-flame ionization detection (LVI-GC-FID) was developed. The goal of this study was to determine mineral oil saturated hydrocarbons (MOSH) in camellia seed oils. The purification condition of SPE columns with silver impregnated the activated silica gel and activated aluminum oxide was optimized. The optimal SPE cartridge was loaded with 10 g of Ag-activated silica gel per 10 g of activated aluminum oxide. The PTV initial temperature was set at 75℃ for 1 min (split 200:1), and heated from 75℃ to 370℃ at 250℃/min. Then the diverter valve was closed for 1 min and opened again with the split flow ratio changing to 50:1. The injection volume was 40 μL. The calibration curve of paraffin oil was liner in the range of 5-500 mg/kg with correlation coefficient of 0.998. The detection limit (LOD) and the quantification limit (LOQ) of paraffin oils in hexane were 0.26 mg/kg and 0.80 mg/kg, respectively. The recoveries from spiked oil samples were between 93.3% and 112.7%, with relative standard deviation (RSD) of 1.8%-5.2%, the RSD of intra-day and inter-day were less than 2.6% . This procedure was applied to analyze the MOSH in 11 commercial camellia seed oils and the contamination was found to range from 6.8 mg/kg to 76.7 mg/kg. The method is simple in operation with high sensitivity, good reproducibility and low cost, and suitable for determination of MOSH in vegetable oils.
2016, 44(9): 1425-1431
doi: 10.11895/j.issn.0253-3820.160062
Abstract:
An analytical method was developed for the determination of unsymmetrical dimethylhydrazine (UDMH) in soil samples by gas chromatography-mass spectrometry with the pretreatment of alkaline distillation and ultrasonic derivatization. After pretreated by the alkaline distillation, the quantitative analysis of UDMH was conducted in selected ion monitoring (SIM) mode by using salicylaldehyde as derivatization reagent and ultrasonic to accelerate the derivative reaction. The characteristic ion of the derivative product named salicylaldehyde dimethylhydrazone was m/z 164. Impact factors including types of the alkaline distillation and the derivative conditions with ultrasonic were investigated. The conditions of derivatization were optimized. Under the optimal conditions, linear range of the method was 0.4-30 mg/L. The limit of detection (LOD, S/N=3) was 0.0078 mg/kg. The method was used to detect total UDMH in real soil samples with known concentration. The recoveries ranged from 76% to 108% with relative standard deviations (RSD) of 12%-19% at different spiked concentration levels from 10 mg/kg to 100 mg/kg. In comparison with the methods of spectrophotometry and Soxhlet extraction-ultrasonic derivatization, this method had lower detection limit, and could be used to detect total UDMH in soil samples.
An analytical method was developed for the determination of unsymmetrical dimethylhydrazine (UDMH) in soil samples by gas chromatography-mass spectrometry with the pretreatment of alkaline distillation and ultrasonic derivatization. After pretreated by the alkaline distillation, the quantitative analysis of UDMH was conducted in selected ion monitoring (SIM) mode by using salicylaldehyde as derivatization reagent and ultrasonic to accelerate the derivative reaction. The characteristic ion of the derivative product named salicylaldehyde dimethylhydrazone was m/z 164. Impact factors including types of the alkaline distillation and the derivative conditions with ultrasonic were investigated. The conditions of derivatization were optimized. Under the optimal conditions, linear range of the method was 0.4-30 mg/L. The limit of detection (LOD, S/N=3) was 0.0078 mg/kg. The method was used to detect total UDMH in real soil samples with known concentration. The recoveries ranged from 76% to 108% with relative standard deviations (RSD) of 12%-19% at different spiked concentration levels from 10 mg/kg to 100 mg/kg. In comparison with the methods of spectrophotometry and Soxhlet extraction-ultrasonic derivatization, this method had lower detection limit, and could be used to detect total UDMH in soil samples.
2016, 44(9): 1432-1436
doi: 10.11895/j.issn.0253-3820.150968
Abstract:
In this study, a neutral desorption-extractive electrospray ionization mass spectrometry (ND-EESI-MS) method was developed for the direct and rapid detection of dichlorvos (DDVP) in honey samples without any sample pretreatment procedure. Under the positive ionization mode, the main characteristic parent ion of DDVP was m/z 223 (MW: 222) and daughter ions were m/z 109 and m/z127. Under the optimized working conditions, with the signal intensity of m/z 127 as quantitative index, the quantitative information of DDVP residues in honey was acquired effectively. The results showed that the linear range of DDVP for spiked honey was 5-1000 ng/mL (R2=0.998) with the limit of detection (LOD) of 1.0 ng/mL (n=3) and the recoveries for the DDVP spiked honey samples at the concentration levels of 10, 30 and 400 ng/mL were 93.0%-103.0%, with the relative standard deviations (RSDs, n=6) of less than 4.4%. Meanwhile, for detection of spiked honey with gas chromatography-flame photometric detector (GC-FPD), the linear range was 5-1000 ng/mL (R2=0.999) with the LOD of 1.6 ng/mL(n=3), and the recoveries of DDVP at the spiked honey concentration levels of 10, 30 and 400 ng/mL were 94.9%-110.3%, with the RSDs of less than 7.6%.
In this study, a neutral desorption-extractive electrospray ionization mass spectrometry (ND-EESI-MS) method was developed for the direct and rapid detection of dichlorvos (DDVP) in honey samples without any sample pretreatment procedure. Under the positive ionization mode, the main characteristic parent ion of DDVP was m/z 223 (MW: 222) and daughter ions were m/z 109 and m/z127. Under the optimized working conditions, with the signal intensity of m/z 127 as quantitative index, the quantitative information of DDVP residues in honey was acquired effectively. The results showed that the linear range of DDVP for spiked honey was 5-1000 ng/mL (R2=0.998) with the limit of detection (LOD) of 1.0 ng/mL (n=3) and the recoveries for the DDVP spiked honey samples at the concentration levels of 10, 30 and 400 ng/mL were 93.0%-103.0%, with the relative standard deviations (RSDs, n=6) of less than 4.4%. Meanwhile, for detection of spiked honey with gas chromatography-flame photometric detector (GC-FPD), the linear range was 5-1000 ng/mL (R2=0.999) with the LOD of 1.6 ng/mL(n=3), and the recoveries of DDVP at the spiked honey concentration levels of 10, 30 and 400 ng/mL were 94.9%-110.3%, with the RSDs of less than 7.6%.
2016, 44(9): 1437-1446
doi: 10.11895/j.issn.0253-3820.160201
Abstract:
The single molecule imaging and technologies that developed in 1990s have successfully probed the dynamics of single molecule enzyme catalysis in real time in vitro. Ever since then, single molecule enzymology has entered the golden age of rapid developing. Individual features of each enzyme hidden in the overall average have been discovered, and many new catalytic mechanisms have been proposed. Single molecule enzymology sheds light on the dynamic interactions between enzymes and substrates or products, deepening the understanding of biochemical reactions. This review described the recent research progresses of single molecule protease and ribozyme.
The single molecule imaging and technologies that developed in 1990s have successfully probed the dynamics of single molecule enzyme catalysis in real time in vitro. Ever since then, single molecule enzymology has entered the golden age of rapid developing. Individual features of each enzyme hidden in the overall average have been discovered, and many new catalytic mechanisms have been proposed. Single molecule enzymology sheds light on the dynamic interactions between enzymes and substrates or products, deepening the understanding of biochemical reactions. This review described the recent research progresses of single molecule protease and ribozyme.
2016, 44(9): 1447-1457
doi: 10.11895/j.issn.0253-3820.160341
Abstract:
Hydrogen evolution from water electrolysis is one of the effective ways to obtain clean hydrogen energy in the future. Pt-based materials are the efficient catalysts in hydrogen evolution reaction, but it is expensive, difficult to recycle, which impedes its application in the development of hydrogen energy and economy. Therefore, it is the key trend to develop efficient non-noble metal electrocatalysts with the aim of providing cost-competitive hydrogen energy. In this review, we highlighted the recent research efforts toward the synthesis of noble metal-free electrocatalysts for the hydrogen evolution reaction (HER), mainly focusing on nanomaterial catalysts supported on carbon fiber materials. We reviewed several important kinds of heterogeneous non-noble metal electrocatalysts, including sulfides, selenides, carbides, phosphides, and oxides. In the discussion, emphasis was given to the synthetic methods of these HER electrocatalysts, and the strategies for performance improvement. In addition, this paper also briefly summarized the application of carbon fiber material as substrate in the field of electroanalytical chemistry.
Hydrogen evolution from water electrolysis is one of the effective ways to obtain clean hydrogen energy in the future. Pt-based materials are the efficient catalysts in hydrogen evolution reaction, but it is expensive, difficult to recycle, which impedes its application in the development of hydrogen energy and economy. Therefore, it is the key trend to develop efficient non-noble metal electrocatalysts with the aim of providing cost-competitive hydrogen energy. In this review, we highlighted the recent research efforts toward the synthesis of noble metal-free electrocatalysts for the hydrogen evolution reaction (HER), mainly focusing on nanomaterial catalysts supported on carbon fiber materials. We reviewed several important kinds of heterogeneous non-noble metal electrocatalysts, including sulfides, selenides, carbides, phosphides, and oxides. In the discussion, emphasis was given to the synthetic methods of these HER electrocatalysts, and the strategies for performance improvement. In addition, this paper also briefly summarized the application of carbon fiber material as substrate in the field of electroanalytical chemistry.
2016, 44(9): 1458-1464
doi: 10.11895/j.issn.0253-3820.160108
Abstract:
A dual-mode recording system used for synchronous detection of neuroeletrical and neurochemical signals was developed, and a dual-mode synchronous detection experiment was carried out using the instrument. The device comprised 64-channel neuroelectricity recording module with voltage resolution of 0.3 μV and 4-channel neurochemistry recording module with current resolution of 1 pA. The software had many basic features, including Spike separation and sort, chronoamperometry, cyclic voltammetry, etc. In particular, the software could observe and analyze the dual-mode neural signals synchronously. The performance of the system was demonstrated in the single mode detection experiments. In neuroeletrical experiments, 64-channel simulate neural signals were detected and the signal to noise ratio (S/N) of Spike recorded from cortex of Sprague-Dawley (SD) rat was 6. In the K3[Fe(CN)6] and ascorbic acid measurement experiments, the current response of K3[Fe(CN)6] in the range of 0.1-10 mmol/L was obtained by cyclic voltammetry, with a correlation coefficient of 0.9889, and the current response of ascorbic acid (concentration: 10-800 μmol/L) by chronoamperometry increased linearly with a correlation coefficient of 0.9841. Based on the rat model of global cerebral ischemia, a dual-mode detection experiment was carried out. In the experiment, the neuroelectrical and neurochemical signals were synchronously recorded in the SD rat primary visual cortex. According to the experimental results, we got the conclusion that the concentration of ascorbic acid negatively related to the Spike firing in the SD rat primary visual cortex.
A dual-mode recording system used for synchronous detection of neuroeletrical and neurochemical signals was developed, and a dual-mode synchronous detection experiment was carried out using the instrument. The device comprised 64-channel neuroelectricity recording module with voltage resolution of 0.3 μV and 4-channel neurochemistry recording module with current resolution of 1 pA. The software had many basic features, including Spike separation and sort, chronoamperometry, cyclic voltammetry, etc. In particular, the software could observe and analyze the dual-mode neural signals synchronously. The performance of the system was demonstrated in the single mode detection experiments. In neuroeletrical experiments, 64-channel simulate neural signals were detected and the signal to noise ratio (S/N) of Spike recorded from cortex of Sprague-Dawley (SD) rat was 6. In the K3[Fe(CN)6] and ascorbic acid measurement experiments, the current response of K3[Fe(CN)6] in the range of 0.1-10 mmol/L was obtained by cyclic voltammetry, with a correlation coefficient of 0.9889, and the current response of ascorbic acid (concentration: 10-800 μmol/L) by chronoamperometry increased linearly with a correlation coefficient of 0.9841. Based on the rat model of global cerebral ischemia, a dual-mode detection experiment was carried out. In the experiment, the neuroelectrical and neurochemical signals were synchronously recorded in the SD rat primary visual cortex. According to the experimental results, we got the conclusion that the concentration of ascorbic acid negatively related to the Spike firing in the SD rat primary visual cortex.
2016, 44(9): 1465-1470
doi: 10.11895/j.issn.0253-3820.160234
Abstract:
A new micro embedded telemetry system was developed for the amperometric sensing detection. Its output voltage range was ±0.5 V and resolution was <1 mV. The current acquisition range was ±1 μA and the minimum resolution was 0.2 nA. This telemetry system was designed based on microprocessor ADuCM360, including a potentiostat, a current detection module and a radio module. And the size was only 24 mm×13 mm×11 mm. The computer software written in LabVIEW language was used for data storage and display. In order to verify the accuracy and reliability of this system, an electrical performance test was performed. The current response for ascorbic acid with different concentration was recorded by using the telemetry system. The potential of working electrode was set as 30 mV, and the current response of ascorbic acid electrode had a good linear relationship with its concentration within the concentration range of 50-300 μmol/L. Linear equation was I(nA)=2.98CAA(μmol/L)-137.39, and linear correlation coefficient R2=0.984. Moreover, the applicability of the instrument in the study for living animals was explored by using the cerebral ischemia as model.
A new micro embedded telemetry system was developed for the amperometric sensing detection. Its output voltage range was ±0.5 V and resolution was <1 mV. The current acquisition range was ±1 μA and the minimum resolution was 0.2 nA. This telemetry system was designed based on microprocessor ADuCM360, including a potentiostat, a current detection module and a radio module. And the size was only 24 mm×13 mm×11 mm. The computer software written in LabVIEW language was used for data storage and display. In order to verify the accuracy and reliability of this system, an electrical performance test was performed. The current response for ascorbic acid with different concentration was recorded by using the telemetry system. The potential of working electrode was set as 30 mV, and the current response of ascorbic acid electrode had a good linear relationship with its concentration within the concentration range of 50-300 μmol/L. Linear equation was I(nA)=2.98CAA(μmol/L)-137.39, and linear correlation coefficient R2=0.984. Moreover, the applicability of the instrument in the study for living animals was explored by using the cerebral ischemia as model.
