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2017 Volume 45 Issue 4
2017, 45(4): 465-470
doi: 10.11895/j.issn.0253-3820.160803
Abstract:
Collagen fibrils and hydroxyapatite might recognize each other at the mesoscale by multiple cooperative interactions due to their intrinsically repetitive structured surfaces, and thus effectively directing the biomineralization, a biological process involving regulating the growth of bones, teeth and other organs. In this work, we developed a simple technique to prepare nanowire arrays of biological macromolecules by reversely using the biomineralization mechanism, with results similar to the hot wall epitaxy, a molecular beam deposition technique under vacuum. With this technique, we successfully cultured 5-10 μg/mL rat tail type I collagen monomer solutions into collagen nanowire arrays on the mica (001) lattice plane along one unique direction across the whole cleavage surface. The atomic force microscope experiments indicated that the nanowires in the arrays became more crowded with higher monomer concentration, but their width and height remained unchanged, about 60.0 nm and 1.5 nm, respectively. The collagen nanowire coating enhanced the hydrophilicity of the mica surface, reducing the contact angle from 25.8° to 9.5°. Based on the characterization results of electron back scattering diffraction and transmission electron microscope, the collagen nanowires were most likely to be oriented along the mica [110] direction, which validated the quasiepitaxial growth mechanism in more details.
Collagen fibrils and hydroxyapatite might recognize each other at the mesoscale by multiple cooperative interactions due to their intrinsically repetitive structured surfaces, and thus effectively directing the biomineralization, a biological process involving regulating the growth of bones, teeth and other organs. In this work, we developed a simple technique to prepare nanowire arrays of biological macromolecules by reversely using the biomineralization mechanism, with results similar to the hot wall epitaxy, a molecular beam deposition technique under vacuum. With this technique, we successfully cultured 5-10 μg/mL rat tail type I collagen monomer solutions into collagen nanowire arrays on the mica (001) lattice plane along one unique direction across the whole cleavage surface. The atomic force microscope experiments indicated that the nanowires in the arrays became more crowded with higher monomer concentration, but their width and height remained unchanged, about 60.0 nm and 1.5 nm, respectively. The collagen nanowire coating enhanced the hydrophilicity of the mica surface, reducing the contact angle from 25.8° to 9.5°. Based on the characterization results of electron back scattering diffraction and transmission electron microscope, the collagen nanowires were most likely to be oriented along the mica [110] direction, which validated the quasiepitaxial growth mechanism in more details.
2017, 45(4): 471-476
doi: 10.11895/j.issn.0253-3820.160710
Abstract:
A sensitive colorimetric method for the detection of copper ions (Cu2+) was developed based on the surface modification of silver/platinum nanoclusters (Ag/Pt NCs) and regulation of peroxidase-like activity. It was found that 3-mercaptopropionic acid (MPA) could inhibit the catalytic ability of Ag/Pt NCs; however, it lost the inhibition toward catalytic ability of Ag/Pt NCs after oxidized by oxygen through the catalysis of Cu2+. On the basis of this, a colorimetric method was developed for the detection of Cu2+ through measuring the colorimetric signal variation of the TMB-H2O2 reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions. The linear range was 10-100 nmol/L and the detection limit was 5.0 nmol/L (3σ). The above method was also applied to detect real water samples and spiked samples, and the results demonstrated that this method was simple with low cost.
A sensitive colorimetric method for the detection of copper ions (Cu2+) was developed based on the surface modification of silver/platinum nanoclusters (Ag/Pt NCs) and regulation of peroxidase-like activity. It was found that 3-mercaptopropionic acid (MPA) could inhibit the catalytic ability of Ag/Pt NCs; however, it lost the inhibition toward catalytic ability of Ag/Pt NCs after oxidized by oxygen through the catalysis of Cu2+. On the basis of this, a colorimetric method was developed for the detection of Cu2+ through measuring the colorimetric signal variation of the TMB-H2O2 reaction. This method exhibited high sensitivity and selectivity toward Cu2+ over a panel of other metal ions. The linear range was 10-100 nmol/L and the detection limit was 5.0 nmol/L (3σ). The above method was also applied to detect real water samples and spiked samples, and the results demonstrated that this method was simple with low cost.
2017, 45(4): 477-482
doi: 10.11895/j.issn.0253-3820.170086
Abstract:
A method was developed for determination of thirteen amines including seven aliphatic amines, two heterocyclic amines and four aromatic amines in atmospheric particulate matter (PM) by gas chromatography-mass spectrometry (GC-MS). Samples were ultrasonically extracted with ultra-pure water and derivatized with benzenesulfonyl chloride (BSC) under alkaline conditions. The derivatives were extracted with dichloromethane and then detected by GC-MS using DB-5MS chromatographic column. The method detection limit (S/N=3) and quantitation limit (S/N=10) were 0.00008-0.017 μg/mL and 0.00026-0.0565 μg/mL respectively, and the correlation coefficients were 0.9903-0.9996, which indicated that the standard curve had good linear correlation. In addition, the relative standard deviation was less than 30% and the average recovery was 54.4%-159.7% except for methylamine and benzylamine at spiked level of 1.0 μg/mL, showing high precision and accuracy. 9 kinds of amines were detected in the PM2.5 samples collected in Guangzhou city by this method, among which dimethylamine and butylamine accounted for 90% of the total nine amines, which indicated that they were primary amines in PM2.5; while propylamine exhibited the lowest level in PM2.5 with the concentration less than 1.0 ng/m3.
A method was developed for determination of thirteen amines including seven aliphatic amines, two heterocyclic amines and four aromatic amines in atmospheric particulate matter (PM) by gas chromatography-mass spectrometry (GC-MS). Samples were ultrasonically extracted with ultra-pure water and derivatized with benzenesulfonyl chloride (BSC) under alkaline conditions. The derivatives were extracted with dichloromethane and then detected by GC-MS using DB-5MS chromatographic column. The method detection limit (S/N=3) and quantitation limit (S/N=10) were 0.00008-0.017 μg/mL and 0.00026-0.0565 μg/mL respectively, and the correlation coefficients were 0.9903-0.9996, which indicated that the standard curve had good linear correlation. In addition, the relative standard deviation was less than 30% and the average recovery was 54.4%-159.7% except for methylamine and benzylamine at spiked level of 1.0 μg/mL, showing high precision and accuracy. 9 kinds of amines were detected in the PM2.5 samples collected in Guangzhou city by this method, among which dimethylamine and butylamine accounted for 90% of the total nine amines, which indicated that they were primary amines in PM2.5; while propylamine exhibited the lowest level in PM2.5 with the concentration less than 1.0 ng/m3.
2017, 45(4): 483-488
doi: 10.11895/j.issn.0253-3820.160650
Abstract:
The microfluidic channels integrated with microring resonator were designed. The salt coalescence on chip surface caused by liquid volatilization in open environment was avoided and only 30 μL of reaction solution was consumed. These channels significantly reduced the experiment cost. The design, fabrication and characterization of a highly sensitive and label-free silicon-on-insulator (SOI) microring optical resonator integrated with the microfluidic channels were demonstrated. The radius of the microring was 5 μm and the straight waveguide with a width of 450 nm was employed in the microring resonator. The microring resonator device had many advantages such as high sensitivity, label-free and real-time detection. Using different concentrations of ethanol solution with known refractive indices, the refractive index detection sensitivity was 76.09 nm/RIU and the volume refractive index detection limit was 5.25×10-4 RIU. We also demonstrated the label-free quantitative specific detections of human immunoglobulin G (IgG) solutions using an antibody-modified microring resonator by measuring the resonance wavelength shift resulting from refraction index changes causing by the immobilization of antibodies and specific recognition between antibodies and antigens, respectively. The results showed that the microring optical resonator could real-time monitor the reaction between biological molecules, the resonator could be used in the quantitative detection and biological sensing.
The microfluidic channels integrated with microring resonator were designed. The salt coalescence on chip surface caused by liquid volatilization in open environment was avoided and only 30 μL of reaction solution was consumed. These channels significantly reduced the experiment cost. The design, fabrication and characterization of a highly sensitive and label-free silicon-on-insulator (SOI) microring optical resonator integrated with the microfluidic channels were demonstrated. The radius of the microring was 5 μm and the straight waveguide with a width of 450 nm was employed in the microring resonator. The microring resonator device had many advantages such as high sensitivity, label-free and real-time detection. Using different concentrations of ethanol solution with known refractive indices, the refractive index detection sensitivity was 76.09 nm/RIU and the volume refractive index detection limit was 5.25×10-4 RIU. We also demonstrated the label-free quantitative specific detections of human immunoglobulin G (IgG) solutions using an antibody-modified microring resonator by measuring the resonance wavelength shift resulting from refraction index changes causing by the immobilization of antibodies and specific recognition between antibodies and antigens, respectively. The results showed that the microring optical resonator could real-time monitor the reaction between biological molecules, the resonator could be used in the quantitative detection and biological sensing.
2017, 45(4): 489-494
doi: 10.11895/j.issn.0253-3820.160714
Abstract:
A method of qualitative and quantitative analysis on fluid catalytic cracking (FCC) full range gasoline by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF MS) was established. The results showed that paraffins, olefins, naphthenes and aromatics in FCC gasoline had regional and zonal distribution in two-dimensional contour plots. The distinctions of boiling points and polarity between different compounds were used to achieve the accurate separation and determination in GC×GC-TOF MS analysis, and consequently the co-current flow which was often present in the conventional GC analysis was greatly suppressed. The difference of ionizing efficiency between different compounds was modified by response factors, and moreover, a good quantitative dependency was found between the analysis results of GC and GC×GC-TOF MS on FCC gasoline. Due to the high separation resolution, GC×GC-TOF MS gave more accurate results about the group compositions of FCC gasoline. GC×GC-TOF MS provided an effective way with high precision for the characterization of FCC gasoline.
A method of qualitative and quantitative analysis on fluid catalytic cracking (FCC) full range gasoline by comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GC×GC-TOF MS) was established. The results showed that paraffins, olefins, naphthenes and aromatics in FCC gasoline had regional and zonal distribution in two-dimensional contour plots. The distinctions of boiling points and polarity between different compounds were used to achieve the accurate separation and determination in GC×GC-TOF MS analysis, and consequently the co-current flow which was often present in the conventional GC analysis was greatly suppressed. The difference of ionizing efficiency between different compounds was modified by response factors, and moreover, a good quantitative dependency was found between the analysis results of GC and GC×GC-TOF MS on FCC gasoline. Due to the high separation resolution, GC×GC-TOF MS gave more accurate results about the group compositions of FCC gasoline. GC×GC-TOF MS provided an effective way with high precision for the characterization of FCC gasoline.
2017, 45(4): 495-501
doi: 10.11895/j.issn.0253-3820.160831
Abstract:
A novel solid-phase extraction (SPE) adsorbent for simultaneous extraction of atrazine (ATZ) and its metabolites, deisopropylatrazine (DIA) and deethylatrazine (DEA) from environmental water samples was prepared. Polyacrylonitrile nanofibers (PAN NFs) mat was prepared via electrospinning, and was further functionalized to obtain polypyrrole modified polyacrylonitrile nanofibers (PPy-PAN NFs) mat, hydrazine modified polyacrylonitrile nanofibers (NH2-PAN NFs) mat and carboxyl modified polyacrylonitrile (COOH-PAN NFs) mat. The results showed that the adsorption capacity of COOH-PAN NFs mat was better than other three NFs mats in both static (2.0 mg/g) and dynamic (0.19 mg/g) experiments. Meanwhile, the runoff ratios of COOH-PAN NFs mat were the lowest (less than 30.0%) in the adsorption of three analytes, especially for high polar analytes, which showed that the hydrogen bond between carboxyl groups and analytes was the main interactive force. A combination of mat-based SPE and high performance liquid chromatography-diode array detection was further established for determination of 3 analytes in environmental water samples. The recoveries were 81.4%-120.3% and the limits of detection were 0.12 ng/mL for DIA, 0.09 ng/mL for DEA and ATZ, respectively.
A novel solid-phase extraction (SPE) adsorbent for simultaneous extraction of atrazine (ATZ) and its metabolites, deisopropylatrazine (DIA) and deethylatrazine (DEA) from environmental water samples was prepared. Polyacrylonitrile nanofibers (PAN NFs) mat was prepared via electrospinning, and was further functionalized to obtain polypyrrole modified polyacrylonitrile nanofibers (PPy-PAN NFs) mat, hydrazine modified polyacrylonitrile nanofibers (NH2-PAN NFs) mat and carboxyl modified polyacrylonitrile (COOH-PAN NFs) mat. The results showed that the adsorption capacity of COOH-PAN NFs mat was better than other three NFs mats in both static (2.0 mg/g) and dynamic (0.19 mg/g) experiments. Meanwhile, the runoff ratios of COOH-PAN NFs mat were the lowest (less than 30.0%) in the adsorption of three analytes, especially for high polar analytes, which showed that the hydrogen bond between carboxyl groups and analytes was the main interactive force. A combination of mat-based SPE and high performance liquid chromatography-diode array detection was further established for determination of 3 analytes in environmental water samples. The recoveries were 81.4%-120.3% and the limits of detection were 0.12 ng/mL for DIA, 0.09 ng/mL for DEA and ATZ, respectively.
2017, 45(4): 502-507
doi: 10.11895/j.issn.0253-3820.160775
Abstract:
A nitrite electrochemical sensor based on electrodeposition of zirconium dioxide nanoparticles on reduced graphene oxide modified electrode was successfully constructed for the detection of nitrite. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry and amperometric i-t curve. Under the optimal conditions, the amperometric i-t curve response of the electrode showed a linear relationship with nitrite concentration in the range of 3.0×10-7-1.0×10-6 mol/L and 1.0×10-6-6.0×10-6 mol/L, and the detection limit was 1.0×10-7 mol/L (S/N=3). The fabricated sensor exhibited high sensitivity, good stability and high reproducibility. This sensor was applied for the detection of nitrite in sausage samples with favorable recoveries of 93.7%-110.4% and relative standard deviation (RSD) of 1.6%-2.1%.
A nitrite electrochemical sensor based on electrodeposition of zirconium dioxide nanoparticles on reduced graphene oxide modified electrode was successfully constructed for the detection of nitrite. The electrochemical behavior of the modified electrode was investigated by cyclic voltammetry and amperometric i-t curve. Under the optimal conditions, the amperometric i-t curve response of the electrode showed a linear relationship with nitrite concentration in the range of 3.0×10-7-1.0×10-6 mol/L and 1.0×10-6-6.0×10-6 mol/L, and the detection limit was 1.0×10-7 mol/L (S/N=3). The fabricated sensor exhibited high sensitivity, good stability and high reproducibility. This sensor was applied for the detection of nitrite in sausage samples with favorable recoveries of 93.7%-110.4% and relative standard deviation (RSD) of 1.6%-2.1%.
2017, 45(4): 508-513
doi: 10.11895/j.issn.0253-3820.160875
Abstract:
A simple colorimetric method for detection of isocarbophos was developed based on the enhanced peroxidase-like activity of hemin. Hemin could catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2, which made TMB to lose one electron and caused reaction solution color changing from initial transparent to blue-green. Adding isocarbophos improved hemin affinity to substrates, which further enhanced peroxidase-like activity of hemin and made TMB to lose two electrons. The color of TMB solution was further changed from blue-green to yellow, and the degree of color change was proportional to the concentration of isocarbophos. Under the optimal conditions, the present analytical method for isocarbophos detection had a dynamic range from 2 μg/L to 100 μg/L with a detection limit of 1.2 μg/L (3σ). The selectivity assay demonstrated that other organophosphorus pesticides exhibited negligible interferences for isocarbophos detection. The application of the proposed method in the practical samples showed that the mean recovery of isocarbophos was in the range of 94.4%-113.0%, thus it could be widely applied to rapidly and sensitively detect isocarbophos in the agricultural products.
A simple colorimetric method for detection of isocarbophos was developed based on the enhanced peroxidase-like activity of hemin. Hemin could catalyze the oxidation of peroxidase substrate 3,3',5,5'-tetramethylbenzidine (TMB) by H2O2, which made TMB to lose one electron and caused reaction solution color changing from initial transparent to blue-green. Adding isocarbophos improved hemin affinity to substrates, which further enhanced peroxidase-like activity of hemin and made TMB to lose two electrons. The color of TMB solution was further changed from blue-green to yellow, and the degree of color change was proportional to the concentration of isocarbophos. Under the optimal conditions, the present analytical method for isocarbophos detection had a dynamic range from 2 μg/L to 100 μg/L with a detection limit of 1.2 μg/L (3σ). The selectivity assay demonstrated that other organophosphorus pesticides exhibited negligible interferences for isocarbophos detection. The application of the proposed method in the practical samples showed that the mean recovery of isocarbophos was in the range of 94.4%-113.0%, thus it could be widely applied to rapidly and sensitively detect isocarbophos in the agricultural products.
2017, 45(4): 514-520
doi: 10.11895/j.issn.0253-3820.160828
Abstract:
An offline silver-impregnated silica gel solid-phase extraction (Ag-SPE) approach combined with a programmed temperature vaporization-gas chromatography-flame ionization detector (PTV-GC-FID) was proposed for routine analysis of mineral oil saturated hydrocarbons (MOSH) in chocolates. The MOSH in chocolates were extracted by n-hexane and 1 mL of extract was purified by offline Ag-SPE column. The SPE columns packed with 0.3% Ag-activated silica gel were used to separate MOSH from triglycerides and olefins in chocolates. The eluent of MOSH fraction was only 5 mL and then concentrated to 0.2 mL through nitrogen blowing with little evaporation loss. The PTV parameters were as follows: the initial temperature was set at 45℃ and held for 1 min (split ratio was 200:1), then warmed up to 360℃ at linear gradient of 250℃ min-1 and held for 27 min (split valve was closed for 2 min followed by split ratio of 100:1). The GC injection volume was 40 μL. The GC column was heated from 35℃ (3 min) to 350℃ at 25℃/min, and then raised to 370℃ (10 min) at 5℃/min. The flow rate of the carrier gas was 1.3 mL/min (and pressure was 60 kPa), FID temperature was set at 380℃. The limit of quantification (LOQ) and the recoveries of the method were 0.5 mg/kg and 84.9%-108.6%, respectively, with the relative standard deviations (RSD) of 0.2%-1.5%. Twenty-five commercial chocolate samples were analyzed with the proposed method, and it was found that the MOSH in three samples were not detected, and the concentrations of MOSH in other 22 samples were 1.09-8.15 mg/kg (the concentrations of MOSH with C16-C35 component were 0.56-4.43 mg/kg). The results suggested that it was necessary to routinely detect mineral oil contamination in chocolates for food safety.
An offline silver-impregnated silica gel solid-phase extraction (Ag-SPE) approach combined with a programmed temperature vaporization-gas chromatography-flame ionization detector (PTV-GC-FID) was proposed for routine analysis of mineral oil saturated hydrocarbons (MOSH) in chocolates. The MOSH in chocolates were extracted by n-hexane and 1 mL of extract was purified by offline Ag-SPE column. The SPE columns packed with 0.3% Ag-activated silica gel were used to separate MOSH from triglycerides and olefins in chocolates. The eluent of MOSH fraction was only 5 mL and then concentrated to 0.2 mL through nitrogen blowing with little evaporation loss. The PTV parameters were as follows: the initial temperature was set at 45℃ and held for 1 min (split ratio was 200:1), then warmed up to 360℃ at linear gradient of 250℃ min-1 and held for 27 min (split valve was closed for 2 min followed by split ratio of 100:1). The GC injection volume was 40 μL. The GC column was heated from 35℃ (3 min) to 350℃ at 25℃/min, and then raised to 370℃ (10 min) at 5℃/min. The flow rate of the carrier gas was 1.3 mL/min (and pressure was 60 kPa), FID temperature was set at 380℃. The limit of quantification (LOQ) and the recoveries of the method were 0.5 mg/kg and 84.9%-108.6%, respectively, with the relative standard deviations (RSD) of 0.2%-1.5%. Twenty-five commercial chocolate samples were analyzed with the proposed method, and it was found that the MOSH in three samples were not detected, and the concentrations of MOSH in other 22 samples were 1.09-8.15 mg/kg (the concentrations of MOSH with C16-C35 component were 0.56-4.43 mg/kg). The results suggested that it was necessary to routinely detect mineral oil contamination in chocolates for food safety.
2017, 45(4): 521-528
doi: 10.11895/j.issn.0253-3820.160849
Abstract:
The magnetic molecularly imprinted polymers (MMIPs), based on the surface of magnetic nanoparticles being modified by surface grafting, have been successfully synthesized, with dibutyl phthalate (DBP) as template molecule, ethylene glycol dimethacrylate (EGDMA) as cross-linking agent and azobisisobutyronitrile (AIBN) as initiator. Scanning electron microscopy (SEM), transmission electron microscope (TEM), and elemental analysis were employed to characterize the MMIPs. The structure and magnetic properties of the MMIPs were investigated by means of X-ray diffraction and vibrating sample magnetometer. The BET surface area shows that MMIPs is 380 m2/g and MNIPs is 324 m2/g. A series of static adsorption experiments were conducted to analyze its adsorption performance, which followed pseudo-second-order model by the kinetic analysis with correlation coefficient (R2) 0.9797, and Sips equation with correlation coefficient (R2) 0.999 by the isothermal analysis. The imprinting factors of diallyl phthalate (DAP), DBP and di-2-ethylhexyl phthalate (DEHP) were 1.53, 2.21 and 1.39 respectively, showing that MMIPs had better recognition performance for DBP. The experiment of regeneration recycles with five times showed the regeneration ability of DBP was only reduced by 12.3%.
The magnetic molecularly imprinted polymers (MMIPs), based on the surface of magnetic nanoparticles being modified by surface grafting, have been successfully synthesized, with dibutyl phthalate (DBP) as template molecule, ethylene glycol dimethacrylate (EGDMA) as cross-linking agent and azobisisobutyronitrile (AIBN) as initiator. Scanning electron microscopy (SEM), transmission electron microscope (TEM), and elemental analysis were employed to characterize the MMIPs. The structure and magnetic properties of the MMIPs were investigated by means of X-ray diffraction and vibrating sample magnetometer. The BET surface area shows that MMIPs is 380 m2/g and MNIPs is 324 m2/g. A series of static adsorption experiments were conducted to analyze its adsorption performance, which followed pseudo-second-order model by the kinetic analysis with correlation coefficient (R2) 0.9797, and Sips equation with correlation coefficient (R2) 0.999 by the isothermal analysis. The imprinting factors of diallyl phthalate (DAP), DBP and di-2-ethylhexyl phthalate (DEHP) were 1.53, 2.21 and 1.39 respectively, showing that MMIPs had better recognition performance for DBP. The experiment of regeneration recycles with five times showed the regeneration ability of DBP was only reduced by 12.3%.
2017, 45(4): 529-536
doi: 10.11895/j.issn.0253-3820.160808
Abstract:
An efficient method for the analysis of multiclass plant growth regulators and pesticide (imidacloprid, acetamiprid) residues in tea was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with acetonitrile/formic acid (99:1, V/V) solution, cleaned up with four sorbents including C18, strong anion exchanger (SAX), primary secondary amine (PSA) and anhydrous MgSO4. The compounds were separated on a HSS T3 column under positive/negative electrospray ionization mode, detected by scheduled multiple reaction monitoring (SMRM), and quantified by matrix-matched external standard curves. All pesticide residues showed good linearity in the concentration range of 1-200 μg/L (6-benzylaminopurine, paclobutrazol, uniconazole, forchlorfenuron, mepiquat chloride, imidacloprid, acetamiprid) or 5-1000 μg/L (2,4-dichlor-ophenoxyacetic acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, gibberellic acid, 1-naphthaleneacetic acid, indole-3-butyric acid) , with correlation coefficient (R2≥0.99). Limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) were 0.18-9.68 μg/kg and 0.61-32.26 μg/kg, respectively. In addition, the spiked recoveries of tea samples were 73.1%-108.9%, and RSDs were 0.6%-8.0%. This method was applied to commercial samples, and all the detections were confirmed by acquiring transitions for each pesticide in the samples.
An efficient method for the analysis of multiclass plant growth regulators and pesticide (imidacloprid, acetamiprid) residues in tea was developed based on ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The samples were extracted with acetonitrile/formic acid (99:1, V/V) solution, cleaned up with four sorbents including C18, strong anion exchanger (SAX), primary secondary amine (PSA) and anhydrous MgSO4. The compounds were separated on a HSS T3 column under positive/negative electrospray ionization mode, detected by scheduled multiple reaction monitoring (SMRM), and quantified by matrix-matched external standard curves. All pesticide residues showed good linearity in the concentration range of 1-200 μg/L (6-benzylaminopurine, paclobutrazol, uniconazole, forchlorfenuron, mepiquat chloride, imidacloprid, acetamiprid) or 5-1000 μg/L (2,4-dichlor-ophenoxyacetic acid, 4-chlorophenoxyacetic acid, indole-3-acetic acid, gibberellic acid, 1-naphthaleneacetic acid, indole-3-butyric acid) , with correlation coefficient (R2≥0.99). Limits of detection (LOD, S/N=3) and limits of quantitation (LOQ, S/N=10) were 0.18-9.68 μg/kg and 0.61-32.26 μg/kg, respectively. In addition, the spiked recoveries of tea samples were 73.1%-108.9%, and RSDs were 0.6%-8.0%. This method was applied to commercial samples, and all the detections were confirmed by acquiring transitions for each pesticide in the samples.
2017, 45(4): 537-544
doi: 10.11895/j.issn.0253-3820.160740
Abstract:
A method of high performance liquid chromatography coupled with time-of-flight mass spectrometry was used to detect the endogenous metabolites changes in plasma of normal rats, rats of dampness stagnancy due to spleen deficiency and Astragalus flavone component intervention rats. Metabolism map of rat plasma was obtained and the mechanism of Astragalus flavonoids on dampness stagnancy due to spleen deficiency was studied. Rat model with dampness stagnancy due to spleen deficiency was established by high fat and low protein diet plus load swimming. Liquid chromatography tandem mass spectrometry was used for the analysis of rat plasma sample, and 0.05% formic acid water with 0.05% formic acid acetonitrile as the mobile phase was applied in gradient elution with Halo C18 chromatographic column. In this study, partial least squares discriminant analysis and variance analysis were used to screen the potential biomarkers, it was found that the metabolic profile of the Astragalus flavonoids was different from that of the model group, which was close to that of the normal group. A total of 11 potential biomarkers were identified, including glycerol phospholipids, sphingolipids, amino acids, and so on. The metabolic pathways of biomarkers including three tricarboxylic acid cycle, glycerol phospholipid metabolism, fatty acid metabolism, amino acid metabolism and so on, which mainly related to energy metabolism and fat metabolism in the body. Related indexes of rats with syndrome of spleen deficiency of water and dampness were significantly callback after Astragalus flavone intervention, including macro indicators such as body weight, independent activities and micro indicators such as metabolic markers, blood lipids and others. The result showed that Astragalus flavonoids played the role of strengthening the spleen and draining the water mainly through regulating the energy metabolism, fat metabolism and so on.
A method of high performance liquid chromatography coupled with time-of-flight mass spectrometry was used to detect the endogenous metabolites changes in plasma of normal rats, rats of dampness stagnancy due to spleen deficiency and Astragalus flavone component intervention rats. Metabolism map of rat plasma was obtained and the mechanism of Astragalus flavonoids on dampness stagnancy due to spleen deficiency was studied. Rat model with dampness stagnancy due to spleen deficiency was established by high fat and low protein diet plus load swimming. Liquid chromatography tandem mass spectrometry was used for the analysis of rat plasma sample, and 0.05% formic acid water with 0.05% formic acid acetonitrile as the mobile phase was applied in gradient elution with Halo C18 chromatographic column. In this study, partial least squares discriminant analysis and variance analysis were used to screen the potential biomarkers, it was found that the metabolic profile of the Astragalus flavonoids was different from that of the model group, which was close to that of the normal group. A total of 11 potential biomarkers were identified, including glycerol phospholipids, sphingolipids, amino acids, and so on. The metabolic pathways of biomarkers including three tricarboxylic acid cycle, glycerol phospholipid metabolism, fatty acid metabolism, amino acid metabolism and so on, which mainly related to energy metabolism and fat metabolism in the body. Related indexes of rats with syndrome of spleen deficiency of water and dampness were significantly callback after Astragalus flavone intervention, including macro indicators such as body weight, independent activities and micro indicators such as metabolic markers, blood lipids and others. The result showed that Astragalus flavonoids played the role of strengthening the spleen and draining the water mainly through regulating the energy metabolism, fat metabolism and so on.
2017, 45(4): 545-552
doi: 10.11895/j.issn.0253-3820.160493
Abstract:
A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of bistrifluron, cyantraniliprole and SYP9080 residues in fruits and vegetables. The analytes were extracted from samples with acetonitrile, and purified by dispersion solid phase extraction using C18 and primary secondary amine (PSA) as solid phase adsorbent, then analyzed by LC-MS/MS. Bistrifluron and SYP9080 were analyzed with negative ion multiple-reaction monitoring (MRM), cyantraniliprole was analyzed with positive ion MRM. The matrix-induced weakening effect was observed in the analysis of cyantraniliprole and SYP9080 in several samples including cucumber, apple and onion, and the weakening extent of the matrix-induced effect depended on the sample properties. But no matrix effect was found in the analysis of bistrifluron in several samples. The interference of matrix was reduced by using the matrix-matched calibration standards curve in the analysis of cyantraniliprole and SYP9080. Bistrifluron could be quantified by an external standard of the matrix-matched calibration standards or the pure solvent calibration standards. The linear range was from 0.2 μg/L to 100 μg/L for bistrifluron, cyantraniliprole and SYP9080 with the good correlation coefficients (r≥0.9990). The recoveries of cucumber, grape, apple and scallion added bistrifluron at 0.005-2 mg/kg were 79.8%-99.9%, with relative standard deviations (RSD) of 3.6%-9.8%. The limits of quantification (S/N=10) were 0.210 μg/kg, 0.160 μg/kg and 0.004 μg/kg, and limits of detection (S/N=3) were 0.064 μg/kg, 0.048 μg/kg and 0.001 μg/kg for bistrifluron, cyantraniliprole and SYP9080, respectively.
A liquid chromatography-tandem mass spectrometric (LC-MS/MS) method was developed for the determination of bistrifluron, cyantraniliprole and SYP9080 residues in fruits and vegetables. The analytes were extracted from samples with acetonitrile, and purified by dispersion solid phase extraction using C18 and primary secondary amine (PSA) as solid phase adsorbent, then analyzed by LC-MS/MS. Bistrifluron and SYP9080 were analyzed with negative ion multiple-reaction monitoring (MRM), cyantraniliprole was analyzed with positive ion MRM. The matrix-induced weakening effect was observed in the analysis of cyantraniliprole and SYP9080 in several samples including cucumber, apple and onion, and the weakening extent of the matrix-induced effect depended on the sample properties. But no matrix effect was found in the analysis of bistrifluron in several samples. The interference of matrix was reduced by using the matrix-matched calibration standards curve in the analysis of cyantraniliprole and SYP9080. Bistrifluron could be quantified by an external standard of the matrix-matched calibration standards or the pure solvent calibration standards. The linear range was from 0.2 μg/L to 100 μg/L for bistrifluron, cyantraniliprole and SYP9080 with the good correlation coefficients (r≥0.9990). The recoveries of cucumber, grape, apple and scallion added bistrifluron at 0.005-2 mg/kg were 79.8%-99.9%, with relative standard deviations (RSD) of 3.6%-9.8%. The limits of quantification (S/N=10) were 0.210 μg/kg, 0.160 μg/kg and 0.004 μg/kg, and limits of detection (S/N=3) were 0.064 μg/kg, 0.048 μg/kg and 0.001 μg/kg for bistrifluron, cyantraniliprole and SYP9080, respectively.
2017, 45(4): 553-559
doi: 10.11895/j.issn.0253-3820.160833
Abstract:
A method was developed for the determination of imidacloprid and its metabolites imidacloprid olefin, imidacloprid urea and 6-chloronicotinic acid in honey and bee pollen by liquid chromatography tandem mass spectrometry (LC-MS/MS). On the basis of typical QuEChERS method, the pH and times of extraction solvent, sorbents were optimized to ensure the extraction efficiency and the purification of extraction. Finally, the method was developed as follows: matrix was extracted with 5% formic acid-acetonitrile twice, and the extraction was cleaned with enhanced matrix removal-lipid (EMR), detected with LC-MS/MS and quantified with external matrix standards. The results indicated that the average spiked recoveries of imidacloprid, imidacloprid olefin, imidacloprid urea and 6-chloronicotinic acid in honey and pollen samples were 86.0%-111.5% with relative standard deviations (RSDs) of 1.7%-9.6%, the LODs were 0.20, 3.50, 0.40 and 14.00 μg/kg, and the LOQs were 0.60, 11.64, 1.20 and 45.00 μg/kg. The method was rapid and simple with high sensitivity and good reproducibility, and suitable for the determination of imidacloprid and its three metabolites residues in honey and bee pollen.
A method was developed for the determination of imidacloprid and its metabolites imidacloprid olefin, imidacloprid urea and 6-chloronicotinic acid in honey and bee pollen by liquid chromatography tandem mass spectrometry (LC-MS/MS). On the basis of typical QuEChERS method, the pH and times of extraction solvent, sorbents were optimized to ensure the extraction efficiency and the purification of extraction. Finally, the method was developed as follows: matrix was extracted with 5% formic acid-acetonitrile twice, and the extraction was cleaned with enhanced matrix removal-lipid (EMR), detected with LC-MS/MS and quantified with external matrix standards. The results indicated that the average spiked recoveries of imidacloprid, imidacloprid olefin, imidacloprid urea and 6-chloronicotinic acid in honey and pollen samples were 86.0%-111.5% with relative standard deviations (RSDs) of 1.7%-9.6%, the LODs were 0.20, 3.50, 0.40 and 14.00 μg/kg, and the LOQs were 0.60, 11.64, 1.20 and 45.00 μg/kg. The method was rapid and simple with high sensitivity and good reproducibility, and suitable for the determination of imidacloprid and its three metabolites residues in honey and bee pollen.
2017, 45(4): 560-564
doi: 10.11895/j.issn.0253-3820.160599
Abstract:
The mesoporous manganese dioxide (MnO2) materials were synthesized by the calcinations of manganese carbonate (MnCO3) precursors in air atmosphere at 300, 350 and 400℃. The slurries of MnO2 and binder were sprayed on the quartz electrodes. Quartz crystal microbalance (QCM) was conducted with cyclic voltammetry to analyze the electrochemical behaviors of the three MnO2 samples in 0.1 mol/L sodium sulfate (Na2SO4). The mass of the three samples were generally increased during potential cycling, especially in the first stage, which suggested that an irreversible reaction process occurred. The as-synthesized MnO2 at 300℃ had the better electrochemical stability and capacity retentivity. The three materials were assembled to (-) active carbon/MnO2 (+) supercapacitors and the charge-discharge tests were conducted. The results showed that 35%-40% capacity loss was occurred in the initial cycling, and the total discharge capacities of MnO2 formed at 300℃, 350℃, 400℃ were 15.9, 12.9, 11.7 mA h/g, respectively. The detection results of QCM method were consistent with that of the charge-discharge tests, suggesting that this QCM method could be used for distinguishing the electrochemical performance of mesoporous MnO2 materials.
The mesoporous manganese dioxide (MnO2) materials were synthesized by the calcinations of manganese carbonate (MnCO3) precursors in air atmosphere at 300, 350 and 400℃. The slurries of MnO2 and binder were sprayed on the quartz electrodes. Quartz crystal microbalance (QCM) was conducted with cyclic voltammetry to analyze the electrochemical behaviors of the three MnO2 samples in 0.1 mol/L sodium sulfate (Na2SO4). The mass of the three samples were generally increased during potential cycling, especially in the first stage, which suggested that an irreversible reaction process occurred. The as-synthesized MnO2 at 300℃ had the better electrochemical stability and capacity retentivity. The three materials were assembled to (-) active carbon/MnO2 (+) supercapacitors and the charge-discharge tests were conducted. The results showed that 35%-40% capacity loss was occurred in the initial cycling, and the total discharge capacities of MnO2 formed at 300℃, 350℃, 400℃ were 15.9, 12.9, 11.7 mA h/g, respectively. The detection results of QCM method were consistent with that of the charge-discharge tests, suggesting that this QCM method could be used for distinguishing the electrochemical performance of mesoporous MnO2 materials.
2017, 45(4): 565-573
doi: 10.11895/j.issn.0253-3820.160800
Abstract:
A liquid chromatography-quadrupole-time-of-flight mass spectrometer(LC-Q/TOF-MS) based urinary metabolomic approach was employed to assess the toxicity-alleviation effect of Huangqi oral solution(HOs) on cisplatin-exposed rats and explore its possible mechanisms. Rat toxicity model was developed by multiple intraperitoneal injection of low-dose cisplatin, while HOs was orally administrated to rats simultaneously for 16 consecutive days to attenuate or reduce the cisplatin-induced toxicity. 24-hour urine samples on day 18 were collected and analyzed using LC-Q/TOF-MS to obtain the dataset of urinary metabolites. Principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were employed to assess the quality of the dataset and screen the potential toxicity-alleviation biomarkers. The serum level of rat creatinine and urea nitrogen on day 20 was determined, and the results showed that successive administration of HOs significantly reduced the cisplatin-induced increase of creatinine and urea nitrogen. PCA cluster analysis clearly demonstrated that HOs could partly improve the CDDP-induced abnormality of metabolic profiling. 35 urinary metabolites were finally screened as the potential biomarkers associated with the toxicity-attenuation effect of HOs, according to the combination of the analysis results of OPLS-DA, t-test and fold change analysis. Further metabolic pathway analysis revealed that HOs could restore the metabolic disorders of amino acid, energy and nucleotide, thereby exerted its toxicity-alleviation effect.
A liquid chromatography-quadrupole-time-of-flight mass spectrometer(LC-Q/TOF-MS) based urinary metabolomic approach was employed to assess the toxicity-alleviation effect of Huangqi oral solution(HOs) on cisplatin-exposed rats and explore its possible mechanisms. Rat toxicity model was developed by multiple intraperitoneal injection of low-dose cisplatin, while HOs was orally administrated to rats simultaneously for 16 consecutive days to attenuate or reduce the cisplatin-induced toxicity. 24-hour urine samples on day 18 were collected and analyzed using LC-Q/TOF-MS to obtain the dataset of urinary metabolites. Principal component analysis(PCA) and orthogonal partial least squares-discriminant analysis(OPLS-DA) were employed to assess the quality of the dataset and screen the potential toxicity-alleviation biomarkers. The serum level of rat creatinine and urea nitrogen on day 20 was determined, and the results showed that successive administration of HOs significantly reduced the cisplatin-induced increase of creatinine and urea nitrogen. PCA cluster analysis clearly demonstrated that HOs could partly improve the CDDP-induced abnormality of metabolic profiling. 35 urinary metabolites were finally screened as the potential biomarkers associated with the toxicity-attenuation effect of HOs, according to the combination of the analysis results of OPLS-DA, t-test and fold change analysis. Further metabolic pathway analysis revealed that HOs could restore the metabolic disorders of amino acid, energy and nucleotide, thereby exerted its toxicity-alleviation effect.
2017, 45(4): 574-578
doi: 10.11895/j.issn.0253-3820.160707
Abstract:
Phenylketonuria (PKU) is a newborn inherited metabolic disorder caused by the genetic deficiency of hepatic enzyme phenylalanine hydroxylase (PAH) which thus in metabolic disorder of phenylalanine. In this study, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was used to analyze the accurate amount of coenzyme Q10 (CoQ10) and the relative amount of CoQ9 in newborn dried blood spot (DBS) collected from 5 PKU newborns (3 and 30 days after birth, respectively) and 20 healthy newborns. The content of CoQ10 was (122.1±24.9 ng/mL) and (59.0±12.0 ng/mL) in DBS from healthy newborns and PKU newborns, respectively. The relative contents of cholesterol and glucose in the DBS were determined by gas chromatography-mass spectrometry (GC-MS). In comparison with healthy newborn group, the levels of CoQ10, CoQ9, cholesterol and glucose were all significantly decreased in PKU newborns. The increased content of Phe and the decreased content of CoQ10 showed significant inverse correlation in the DBS from PKU. This study provides references for diet therapy of PKU newborns.
Phenylketonuria (PKU) is a newborn inherited metabolic disorder caused by the genetic deficiency of hepatic enzyme phenylalanine hydroxylase (PAH) which thus in metabolic disorder of phenylalanine. In this study, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was used to analyze the accurate amount of coenzyme Q10 (CoQ10) and the relative amount of CoQ9 in newborn dried blood spot (DBS) collected from 5 PKU newborns (3 and 30 days after birth, respectively) and 20 healthy newborns. The content of CoQ10 was (122.1±24.9 ng/mL) and (59.0±12.0 ng/mL) in DBS from healthy newborns and PKU newborns, respectively. The relative contents of cholesterol and glucose in the DBS were determined by gas chromatography-mass spectrometry (GC-MS). In comparison with healthy newborn group, the levels of CoQ10, CoQ9, cholesterol and glucose were all significantly decreased in PKU newborns. The increased content of Phe and the decreased content of CoQ10 showed significant inverse correlation in the DBS from PKU. This study provides references for diet therapy of PKU newborns.
2017, 45(4): 579-586
doi: 10.11895/j.issn.0253-3820.160752
Abstract:
Ultrafiltration technology and spectrum technology were used to study the compositional and structural evolution of size-fractionated dissolved organic matter (DOM) during chicken manure composting. Electrochemical method was used to measure electron transfer capacity. The results showed that most of protein-like components were exist in DOM (MW< 1 kDa) and it was the main components in DOM (MW< 1 kDa) during initial composting. The protein-like components were persistently degraded and the humic-like components were persistently generated during composting process. The protein-like components didn't exist in DOM (MW< 1 kDa) and the fulvic-like components were the main components in the end of composting process. The humic-like substances were the main fluoresence components of DOM (MW=1-3 kDa, MW=3-5 kDa, MW>5 kDa). Though the changes of humic-like components with different molecular weight of DOM were different during composting, the content of humic-like components in the end of composting process was higher than that in the initial composting process. The electron donating capacity was persistently reducing and electron accepting capacity was persistently increasing for DOM with MW< 1 kDa in the process of composting. In contrast, for the DOM with MW>1 kDa, the electron donating capacity was persistently increasing and the electron accepting capacity was irregular in the process of composting process. Meanwhile, the change of electron transfer capacity was irregular for DOM with MW = 1-3 kDa and MW=3-5 kDa. In a word, EAC of compost-derived DOM with size-fractionation was controlled by the aromatic carbon content which was derived from lignin degradation, but not related to spectrum parameter.
Ultrafiltration technology and spectrum technology were used to study the compositional and structural evolution of size-fractionated dissolved organic matter (DOM) during chicken manure composting. Electrochemical method was used to measure electron transfer capacity. The results showed that most of protein-like components were exist in DOM (MW< 1 kDa) and it was the main components in DOM (MW< 1 kDa) during initial composting. The protein-like components were persistently degraded and the humic-like components were persistently generated during composting process. The protein-like components didn't exist in DOM (MW< 1 kDa) and the fulvic-like components were the main components in the end of composting process. The humic-like substances were the main fluoresence components of DOM (MW=1-3 kDa, MW=3-5 kDa, MW>5 kDa). Though the changes of humic-like components with different molecular weight of DOM were different during composting, the content of humic-like components in the end of composting process was higher than that in the initial composting process. The electron donating capacity was persistently reducing and electron accepting capacity was persistently increasing for DOM with MW< 1 kDa in the process of composting. In contrast, for the DOM with MW>1 kDa, the electron donating capacity was persistently increasing and the electron accepting capacity was irregular in the process of composting process. Meanwhile, the change of electron transfer capacity was irregular for DOM with MW = 1-3 kDa and MW=3-5 kDa. In a word, EAC of compost-derived DOM with size-fractionation was controlled by the aromatic carbon content which was derived from lignin degradation, but not related to spectrum parameter.
2017, 45(4): 587-592
doi: 10.11895/j.issn.0253-3820.160826
Abstract:
Ion trap performances are investigated based on digital ion trap technique with different collision gases at different pressures. Collision gases of helium (4 amu), nitrogen (28 amu) and argon (40 amu) with various pressures are adopted in ion excitation and dissociation stages to investigate the ion trap performances, including mass resolution, signal intensity, tandem mass spectrometric analysis ability and low-mass cut off (LMCO) effect. It is found that when heavy gas of argon is used, energy can be efficiently transferred and LMCO effect is decreased with higher ion capture and dissociation efficiencies but with low mass resolution. Higher mass resolution is realized with helium as collision gas. Furthermore, at the same gas pressure, heavy gas is beneficial to abundant fragment ions and structural information of precursor ion.
Ion trap performances are investigated based on digital ion trap technique with different collision gases at different pressures. Collision gases of helium (4 amu), nitrogen (28 amu) and argon (40 amu) with various pressures are adopted in ion excitation and dissociation stages to investigate the ion trap performances, including mass resolution, signal intensity, tandem mass spectrometric analysis ability and low-mass cut off (LMCO) effect. It is found that when heavy gas of argon is used, energy can be efficiently transferred and LMCO effect is decreased with higher ion capture and dissociation efficiencies but with low mass resolution. Higher mass resolution is realized with helium as collision gas. Furthermore, at the same gas pressure, heavy gas is beneficial to abundant fragment ions and structural information of precursor ion.
2017, 45(4): 593-600
doi: 10.11895/j.issn.0253-3820.160735
Abstract:
A method was developed for simultaneous determination of multiple persistent organic pollutants (POPs) such as hexabromocyclododecanes (HBCDs), polybrominateddiphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in human breast milk. The sample pretreatment procedures included liquid-liquid extraction, gel permeation chromatography (GPC), and solid-phase extraction (SPE) clean-up. Gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) were applied in analysis of the target compounds. By using GPC to remove high-molecular mass lipids and SPE for further clean-up and separation of target compounds, the interferences of biological matrix were greatly reduced. The developed sample pretreatment procedure was suitable for the multi-component analysis of POPs in human samples which had very lower POPs concentrations and smaller sample volumes. The simultaneous determination of PCBs and OCPs by GC-MS/MS exhibited excellent sensitivity and selectivity. The method recoveries were tested by spiked target compounds into fetal bovine serum samples. The recoveries were 88.7%-98.8% for PBDEs, 88.5%-92.5% for HBCDs, 67.9%-82.3% for PCBs, and 81.7%-116.1% for OCPs, respectively. Limits of detection of the method were in the range of 0.13-1.8 ng/L for PBDEs, 0.31-1.2 ng/L for HBCDs, 0.22-1.4 ng/L for PCBs, and 0.20-1.5 ng/L for OCPs, respectively. Finally, the developed method was applied in POPs analysis of 20 human breast milk samples from Weifang city. The results showed that the median concentrations of HBCDs, PBDEs, PCB, HCHS and DDTs were 2.86, 7.76, 8.84, 140 and 503 ng/g lipid weight, respectively. Levels of the target compounds were comparable to those reported in human breast milk for general population from other regions in China.
A method was developed for simultaneous determination of multiple persistent organic pollutants (POPs) such as hexabromocyclododecanes (HBCDs), polybrominateddiphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), and organochlorine pesticides (OCPs) in human breast milk. The sample pretreatment procedures included liquid-liquid extraction, gel permeation chromatography (GPC), and solid-phase extraction (SPE) clean-up. Gas chromatography coupled with mass spectrometry (GC-MS), liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS), and gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) were applied in analysis of the target compounds. By using GPC to remove high-molecular mass lipids and SPE for further clean-up and separation of target compounds, the interferences of biological matrix were greatly reduced. The developed sample pretreatment procedure was suitable for the multi-component analysis of POPs in human samples which had very lower POPs concentrations and smaller sample volumes. The simultaneous determination of PCBs and OCPs by GC-MS/MS exhibited excellent sensitivity and selectivity. The method recoveries were tested by spiked target compounds into fetal bovine serum samples. The recoveries were 88.7%-98.8% for PBDEs, 88.5%-92.5% for HBCDs, 67.9%-82.3% for PCBs, and 81.7%-116.1% for OCPs, respectively. Limits of detection of the method were in the range of 0.13-1.8 ng/L for PBDEs, 0.31-1.2 ng/L for HBCDs, 0.22-1.4 ng/L for PCBs, and 0.20-1.5 ng/L for OCPs, respectively. Finally, the developed method was applied in POPs analysis of 20 human breast milk samples from Weifang city. The results showed that the median concentrations of HBCDs, PBDEs, PCB, HCHS and DDTs were 2.86, 7.76, 8.84, 140 and 503 ng/g lipid weight, respectively. Levels of the target compounds were comparable to those reported in human breast milk for general population from other regions in China.
2017, 45(4): 601-610
doi: 10.11895/j.issn.0253-3820.160817
Abstract:
Perfluorinated compounds (PFCs), a group of persistent organic pollutants, have been widely detected in environmental media and posed great threat to human health. The researches on environmental pollution and health concern of PFCs are the hotspot areas. Because PFCs contain lots of homologs and isomers which are detected at trace levels (ng/g or μg/L) in environment, advanced and reliable analytical methods for determination of PFCs in environment are urgently needed. At present, studies on analytical methods of trace PFCs in environmental samples have been widely carried out in China and abroad. However, systematic review on the sample pretreatment, analytical method, and matrix effect of PFCs determination in complex environmental matrixes is relatively scarce. Therefore, this paper reviews the pretreatment methods, martix effects, and detection techniques (especailly isomers) of PFCs in environment samples (water, sediment/sluge, soil and plant). We hope that this review may provide valuable reference for the enviromental researches on PFCs.
Perfluorinated compounds (PFCs), a group of persistent organic pollutants, have been widely detected in environmental media and posed great threat to human health. The researches on environmental pollution and health concern of PFCs are the hotspot areas. Because PFCs contain lots of homologs and isomers which are detected at trace levels (ng/g or μg/L) in environment, advanced and reliable analytical methods for determination of PFCs in environment are urgently needed. At present, studies on analytical methods of trace PFCs in environmental samples have been widely carried out in China and abroad. However, systematic review on the sample pretreatment, analytical method, and matrix effect of PFCs determination in complex environmental matrixes is relatively scarce. Therefore, this paper reviews the pretreatment methods, martix effects, and detection techniques (especailly isomers) of PFCs in environment samples (water, sediment/sluge, soil and plant). We hope that this review may provide valuable reference for the enviromental researches on PFCs.
2017, 45(4): 611-619
doi: 10.11895/j.issn.0253-3820.160908
Abstract:
A 8-channel neural signal's simultaneous transducer detection micro system was developed to research the neural loop located at the brain hippocampus zone. The components of the system contained the neural probe manufactured with the Micro-electro-mechanical-systems (MEMS) technique based on silicon-on-insulator (SOI) substrate, biological low noise chopper-stabilization amplifier, low noise and intermediate speed SAR-ADC converter, reduced and low power ASK/FSK modulation radio transmitter. The micro system was applicable with the characters of small volume, interferences free, neural electrophysiology and neurotransmitter simultaneous detection, high sensitivity, high linearity, etc. The electrode resistance was optimized to 35.0 kΩ after depositing nanometer platinum black on the 4 electrophysiological sites on the Pt electrode. With the modification enzyme technique, nanomaterial enzyme membrane (Pt-mPD-GluOx) was directly fixed on the glutamate detection locus for selectively detecting special neural neurotransmitter matter. In addition, the electrochemistry measurement results indicated that the linear range of glutamate was 6-35 μmol/L with correlation coefficient of 0.97, the sensitivity was 0.0069 pA/(μmol/L). The current response error was less than 3.0 pA, which showed that the neural needle satisfied differential selection. Also, the logic/analog mixed signal 180-nm Application specific integrated circuit (ASIC) technique (SmicRF180 nm 1Poly6M) was used to manufacture the transducer back-end disposing IC chip, and the test results provided some key parameters such as chopper-stabilization amplifier (equivalent in putting noise voltage ≤0.7 μV rms@1 kHz, gain of 71-82 dB, CMRR/PSRR>100 dB), SAR-ADC (ENOB is 12 bits, power consumption is 1.2 mW when maxmium conversion speed is 1 Msps, signal-noise-ratio is 60.9 dB, etc), and ASK/FSK modulation radio transmitter (the PA's outputting power of 4-5 dBm, the radiation range of 10 meters). The micro neural transducer integrated system was convenient and wireless wearable for the research of brain hippocampus region.
A 8-channel neural signal's simultaneous transducer detection micro system was developed to research the neural loop located at the brain hippocampus zone. The components of the system contained the neural probe manufactured with the Micro-electro-mechanical-systems (MEMS) technique based on silicon-on-insulator (SOI) substrate, biological low noise chopper-stabilization amplifier, low noise and intermediate speed SAR-ADC converter, reduced and low power ASK/FSK modulation radio transmitter. The micro system was applicable with the characters of small volume, interferences free, neural electrophysiology and neurotransmitter simultaneous detection, high sensitivity, high linearity, etc. The electrode resistance was optimized to 35.0 kΩ after depositing nanometer platinum black on the 4 electrophysiological sites on the Pt electrode. With the modification enzyme technique, nanomaterial enzyme membrane (Pt-mPD-GluOx) was directly fixed on the glutamate detection locus for selectively detecting special neural neurotransmitter matter. In addition, the electrochemistry measurement results indicated that the linear range of glutamate was 6-35 μmol/L with correlation coefficient of 0.97, the sensitivity was 0.0069 pA/(μmol/L). The current response error was less than 3.0 pA, which showed that the neural needle satisfied differential selection. Also, the logic/analog mixed signal 180-nm Application specific integrated circuit (ASIC) technique (SmicRF180 nm 1Poly6M) was used to manufacture the transducer back-end disposing IC chip, and the test results provided some key parameters such as chopper-stabilization amplifier (equivalent in putting noise voltage ≤0.7 μV rms@1 kHz, gain of 71-82 dB, CMRR/PSRR>100 dB), SAR-ADC (ENOB is 12 bits, power consumption is 1.2 mW when maxmium conversion speed is 1 Msps, signal-noise-ratio is 60.9 dB, etc), and ASK/FSK modulation radio transmitter (the PA's outputting power of 4-5 dBm, the radiation range of 10 meters). The micro neural transducer integrated system was convenient and wireless wearable for the research of brain hippocampus region.
2017, 45(4): 620-625
doi: 10.11895/j.issn.0253-3820.160928
Abstract:
A new type of piezoelectric oscillation-based non-contact spotting mode has been developed to overcome the disadvantages of traditional non-contact spotting modes including complicated operation procedure, cleaning difficulty of spotting needle, large sample consumption of electromagnetic microvalve and high spotting cost of piezoelectric inkjet based non-contact spotting mode. In the device, the capillary spotting needle and the piezoelectric driving device are two independent units used for replacing and cleaning capillary spotting needle. The glass capillary spotting needle is prepared by the laser melting method with adjustable diameter and low cost. The sample spotting volume of the device can be easily adjusted in the range of 10-10-10-9 by changing the amplitude and frequency of piezoelectric ceramic. A microarray spotting system is developed by the combination of the piezoelectric oscillation-based non-contact spotting mode and three dimensional precision displacement control technology. The multiple parameters of as-prepared microarray spotting system have been tested including spotting volume, density of spot and spotting precision. The experimental results indicate that the minimum volume of single spot with 320 pL and the highest density of spot with 4000 spots/cm2 can be achieved by the as-prepared microarray spotting system. Furthermore, the as-prepared microarray spotting system can also be employed to fabricate patterned interface.
A new type of piezoelectric oscillation-based non-contact spotting mode has been developed to overcome the disadvantages of traditional non-contact spotting modes including complicated operation procedure, cleaning difficulty of spotting needle, large sample consumption of electromagnetic microvalve and high spotting cost of piezoelectric inkjet based non-contact spotting mode. In the device, the capillary spotting needle and the piezoelectric driving device are two independent units used for replacing and cleaning capillary spotting needle. The glass capillary spotting needle is prepared by the laser melting method with adjustable diameter and low cost. The sample spotting volume of the device can be easily adjusted in the range of 10-10-10-9 by changing the amplitude and frequency of piezoelectric ceramic. A microarray spotting system is developed by the combination of the piezoelectric oscillation-based non-contact spotting mode and three dimensional precision displacement control technology. The multiple parameters of as-prepared microarray spotting system have been tested including spotting volume, density of spot and spotting precision. The experimental results indicate that the minimum volume of single spot with 320 pL and the highest density of spot with 4000 spots/cm2 can be achieved by the as-prepared microarray spotting system. Furthermore, the as-prepared microarray spotting system can also be employed to fabricate patterned interface.
