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2016 Volume 44 Issue 5
2016, 44(5): 671-677
doi: 10.11895/j.issn.0253-3820.150821
Abstract:
A method was established for the determination of 10 polybrominated diphenyl ethers (PBDEs) in soil using accelerated solvent extraction (ASE), solid phase extraction (SPE) and gas chromatography with electron capture detector (GC-ECD). ASE was used to obtain 10 PBDEs in soil and a good extraction system was investigated by comparison of kinds of extraction systems (n-hexane, n-hexane:acetone (4:1, V/V), n-hexane:acetone (1:1, V/V), and n-hexane:dichloromethane (1:1, V/V)). Besides, 10 kinds of SPE columns with different filters were applied to the purification of 10 PBDEs in soil solution. The optimized conditions were acquired by using the mixture of n-hexane and acetone (4:1, V/V) as extract and acidic silica gel column for the purification. Under the optimized conditions, the average recoveries of 10 PBDEs in soil ranged from 74.4% to 125.2% with the RSDs of 4.4%-14.4%. Method detection limits (MDLs) were 0.04-0.22 ng/mL. The method is simple, rapid and efficient, which has been successfully applied to determine 10 PBDEs in contaminated soil.
A method was established for the determination of 10 polybrominated diphenyl ethers (PBDEs) in soil using accelerated solvent extraction (ASE), solid phase extraction (SPE) and gas chromatography with electron capture detector (GC-ECD). ASE was used to obtain 10 PBDEs in soil and a good extraction system was investigated by comparison of kinds of extraction systems (n-hexane, n-hexane:acetone (4:1, V/V), n-hexane:acetone (1:1, V/V), and n-hexane:dichloromethane (1:1, V/V)). Besides, 10 kinds of SPE columns with different filters were applied to the purification of 10 PBDEs in soil solution. The optimized conditions were acquired by using the mixture of n-hexane and acetone (4:1, V/V) as extract and acidic silica gel column for the purification. Under the optimized conditions, the average recoveries of 10 PBDEs in soil ranged from 74.4% to 125.2% with the RSDs of 4.4%-14.4%. Method detection limits (MDLs) were 0.04-0.22 ng/mL. The method is simple, rapid and efficient, which has been successfully applied to determine 10 PBDEs in contaminated soil.
2016, 44(5): 678-684
doi: 10.11895/j.issn.0253-3820.150789
Abstract:
A derivatization-free method for chloropropanols determination in food using online gel permeation chromatography-gas chromatography-triple quadrupole mass spectrometry (Online GPC-GC-MS/MS) with free of derivatization was established. The target compounds were 3-monochloropropane-1,2-diol (3-MCPD), 2-monochloro-propane-1,3-diol (2-MCPD), 1,3-dichloropropan-2-ol (1,3-DCP) and 2,3-dichloropropan-1-ol (2,3-DCP). Samples were spiked with isotope internal standards, and extracted by matrix solid-supported liquid-liquid extraction on the ExtrelutTM NT absorbent. Hexane was added to wash away the apolar matrix interferences and then ethyl acetate was used to extract the target compounds. The concentrated extracts were directly injected into Online GPC-GC-MS/MS. The good linear relationships for the four types of analytes were obtained in the concentration range of 0.005-1.000 mg/L with correlation coefficients not less than 0.999. The limits of detection and quantitation for chloropropanols in the food samples were in the ranges of 0.002-0.005 mg/kg, and 0.005-0.01 mg/kg respectively. The recoveries and the relative standard deviations (RSD, n=6) for the spiked blank samples at the levels of 0.02, 0.1, 0.5 mg/kg were in the ranges of 94.8%-106.3% (2.2%-10.3%), 91.8%-108.8% (2.1%-10.6%) and 83.1%-109.4% (1.3%-9.4%), respectively. The established method was applied to the samples of soy sauce, hydrolyzed vegetables protein solution and powder, cooking wine, chicken powder, bread and cake, and satisfactory results were acquired.
A derivatization-free method for chloropropanols determination in food using online gel permeation chromatography-gas chromatography-triple quadrupole mass spectrometry (Online GPC-GC-MS/MS) with free of derivatization was established. The target compounds were 3-monochloropropane-1,2-diol (3-MCPD), 2-monochloro-propane-1,3-diol (2-MCPD), 1,3-dichloropropan-2-ol (1,3-DCP) and 2,3-dichloropropan-1-ol (2,3-DCP). Samples were spiked with isotope internal standards, and extracted by matrix solid-supported liquid-liquid extraction on the ExtrelutTM NT absorbent. Hexane was added to wash away the apolar matrix interferences and then ethyl acetate was used to extract the target compounds. The concentrated extracts were directly injected into Online GPC-GC-MS/MS. The good linear relationships for the four types of analytes were obtained in the concentration range of 0.005-1.000 mg/L with correlation coefficients not less than 0.999. The limits of detection and quantitation for chloropropanols in the food samples were in the ranges of 0.002-0.005 mg/kg, and 0.005-0.01 mg/kg respectively. The recoveries and the relative standard deviations (RSD, n=6) for the spiked blank samples at the levels of 0.02, 0.1, 0.5 mg/kg were in the ranges of 94.8%-106.3% (2.2%-10.3%), 91.8%-108.8% (2.1%-10.6%) and 83.1%-109.4% (1.3%-9.4%), respectively. The established method was applied to the samples of soy sauce, hydrolyzed vegetables protein solution and powder, cooking wine, chicken powder, bread and cake, and satisfactory results were acquired.
2016, 44(5): 685-692
doi: 10.11895/j.issn.0253-3820.150948
Abstract:
A metabonomics method based on gas chromatography-mass spectrometry (GC-MS) was established to analyze the changes of intracellular metabolites and study the mechanism of ammonium sulfate enhancing unsaturated fatty acids accumulation in Schizochytrium sp. Metabolites of cells cultivated at 0, 1.5, 2.5 and 3.5 g/L (NH4)2SO4 were analyzed at different times. Heat map was obtained with K-Means algorithm for data clustering analysis. Principal component analysis (PCA) and partial least-squares discrimination analysis (OPLS-DA) were employed for pattern recognition, and an obvious distinction among different conditions was achieved. According to the LS-DA load diagram and variable important factor (VIP) value, 7 biomarkers were determined with significant differences between four different conditions, which were identified as glucose, inositol, mannitol, fructose, phosphoric acid, ethylamine and ethanolamine by searching in NIST and Wiley database. Metabolic pathway analysis indicated that the metabolic flux toward the Embden-Meyerh of-Parnas (EMP) pathway and acetic acid synthesis branch were weakened by ammonium sulfate. Meanwhile, malic enzyme activity increased and the accumulation of NADPH was also enhanced. These might be the reason for the improvement of polyunsaturated fatty acids.
A metabonomics method based on gas chromatography-mass spectrometry (GC-MS) was established to analyze the changes of intracellular metabolites and study the mechanism of ammonium sulfate enhancing unsaturated fatty acids accumulation in Schizochytrium sp. Metabolites of cells cultivated at 0, 1.5, 2.5 and 3.5 g/L (NH4)2SO4 were analyzed at different times. Heat map was obtained with K-Means algorithm for data clustering analysis. Principal component analysis (PCA) and partial least-squares discrimination analysis (OPLS-DA) were employed for pattern recognition, and an obvious distinction among different conditions was achieved. According to the LS-DA load diagram and variable important factor (VIP) value, 7 biomarkers were determined with significant differences between four different conditions, which were identified as glucose, inositol, mannitol, fructose, phosphoric acid, ethylamine and ethanolamine by searching in NIST and Wiley database. Metabolic pathway analysis indicated that the metabolic flux toward the Embden-Meyerh of-Parnas (EMP) pathway and acetic acid synthesis branch were weakened by ammonium sulfate. Meanwhile, malic enzyme activity increased and the accumulation of NADPH was also enhanced. These might be the reason for the improvement of polyunsaturated fatty acids.
2016, 44(5): 693-697
doi: 10.11895/j.issn.0253-3820.150643
Abstract:
A new method for polymorphism detection of rs9263726 site on Psoriasis Susceptibility1 Candidate1(PSORS1C1) was established based on the pyrosequencing technology and the improved method of genomic DNA extraction from whole blood. The detection limit of the method was 0.4 ng/μL genomic DNA. A total of 20 samples were detected by pyrosequencing, and the results were consistent with those of Sanger sequencing. A total of 683 clinical samples were analyzed with pyrosequencing method. The polymorphism distribution of rs9263726 in Chinese populations was summarized as GG (87.6%), GA (11.7%) and AA (0.7%). 46 clinical samples were detected to analyze the relationship between rs9263726 genotype and human leukocyte antigen gene HLA-B*58:01 genotype. The results showed that the genotype of HLA-B*58:01 could be predicted by polymorphism detection of rs9263726 site sequence. The sensitivity of the proposed method was 100%, and the specificity was 91.3%. This study demonstrated a new method for HLA-B*58:01 genotyping.
A new method for polymorphism detection of rs9263726 site on Psoriasis Susceptibility1 Candidate1(PSORS1C1) was established based on the pyrosequencing technology and the improved method of genomic DNA extraction from whole blood. The detection limit of the method was 0.4 ng/μL genomic DNA. A total of 20 samples were detected by pyrosequencing, and the results were consistent with those of Sanger sequencing. A total of 683 clinical samples were analyzed with pyrosequencing method. The polymorphism distribution of rs9263726 in Chinese populations was summarized as GG (87.6%), GA (11.7%) and AA (0.7%). 46 clinical samples were detected to analyze the relationship between rs9263726 genotype and human leukocyte antigen gene HLA-B*58:01 genotype. The results showed that the genotype of HLA-B*58:01 could be predicted by polymorphism detection of rs9263726 site sequence. The sensitivity of the proposed method was 100%, and the specificity was 91.3%. This study demonstrated a new method for HLA-B*58:01 genotyping.
2016, 44(5): 698-706
doi: 10.11895/j.issn.0253-3820.150805
Abstract:
A rapid and sensitive analytical method for the simultaneous determination of 15 organochlorine pesticides (OCPs) and 82 polychlorinated biphenyls (PCBs) in water using accelerate solvent extraction (ASE) and silica gel solid phase extraction (SPE) cleanup followed by gas chromatography-mass spectrometry (GC-MS) analysis was developed. The main potential influence parameters which affected the recoveries of OCPs and PCBs were investigated for the optimum ASE efficiency. Finally, 3 static extraction cycles, 100℃ of extraction temperature, mixture of acetone and hexane (1:1, V/V) as extraction solvent, and 10 min of static extraction time were used. Under the optimized conditions, the recoveries of 15 OCPs and 82 PCBs in spiked water were 70.9%-130% and 52.5%-89.1%, respectively. The intra-day and inter-day relative standard deviation was 1.7%-16.1% and 2.4%-33.3%, respectively. The correlation coefficients (R2) for OCPs and PCBs were above 0.995 in the range of 10-800 μg/L. And the method detection limits were characterized as 0.13-0.38 ng/L for OCPs and 0.10-0.32 ng/L for PCBs. Compared to the traditional methods, the developed method had the advantages of higher recoveries and less consumption of extraction time and toxic solvent. Subsequently, the developed method was applied to measure the concentrations of OCPs and PCBs in the surface water of Beijing. The concentrations of OCPs and PCBs were in the range of not detected (n.d.)-3.45 ng/L and n.d.-4.88 ng/L, respectively.
A rapid and sensitive analytical method for the simultaneous determination of 15 organochlorine pesticides (OCPs) and 82 polychlorinated biphenyls (PCBs) in water using accelerate solvent extraction (ASE) and silica gel solid phase extraction (SPE) cleanup followed by gas chromatography-mass spectrometry (GC-MS) analysis was developed. The main potential influence parameters which affected the recoveries of OCPs and PCBs were investigated for the optimum ASE efficiency. Finally, 3 static extraction cycles, 100℃ of extraction temperature, mixture of acetone and hexane (1:1, V/V) as extraction solvent, and 10 min of static extraction time were used. Under the optimized conditions, the recoveries of 15 OCPs and 82 PCBs in spiked water were 70.9%-130% and 52.5%-89.1%, respectively. The intra-day and inter-day relative standard deviation was 1.7%-16.1% and 2.4%-33.3%, respectively. The correlation coefficients (R2) for OCPs and PCBs were above 0.995 in the range of 10-800 μg/L. And the method detection limits were characterized as 0.13-0.38 ng/L for OCPs and 0.10-0.32 ng/L for PCBs. Compared to the traditional methods, the developed method had the advantages of higher recoveries and less consumption of extraction time and toxic solvent. Subsequently, the developed method was applied to measure the concentrations of OCPs and PCBs in the surface water of Beijing. The concentrations of OCPs and PCBs were in the range of not detected (n.d.)-3.45 ng/L and n.d.-4.88 ng/L, respectively.
Preparation of Poly(Acrylate-Acrylamide) Hydrogel and Its Adsorption Performance to Heavy Metal Ions
2016, 44(5): 707-715
doi: 10.11895/j.issn.0253-3820.150916
Abstract:
By using potassium sulfate and N,N'-methylenebisacrylamide as initiator and acrosslinker, the poly(acrylate-acrylamide) (P(AA-AM)) hydrogel was optimized through orthogonal test and prepared by aqueous polymerization of sodium acrylate and acrylamide. The results of SEM and XPS experiments indicated that the P(AA-AM) hydrogel had three-dimensional network structure with carboxyl and acylamino residues. The carboxyl and acylamino residues could efficiently interact with heavy metal ions to form chelates. The adsorption isotherm and kinetic behavior of Cu2+, Pb2+, Zn2+ and Cd2+ on P(AA-AM) hydrogel were discussed. And the effects of particle size, the temperature, the pH value and the initial concentration of metal ions in solution on the adsorption capacity were investigated. The results showed that the particle size of the P(AA-AM) hydrogel, the pH value and the adsorption temperature of the solution could influence the adsorption reaction. The maximum absorption amounts of 0.097-0.15 mm P(AA-AM) hydrogel to Cu2+, Pb2+, Zn2+ and Cd2+ were 186, 588, 208 and 403 mg/g, respectively under the optimal conditions such as 35℃ and pH 5. The adsorption kinetic followed the pseudo-second-order kinetic mode (R2>0.98) and the adsorption isotherm fit the Langmuir equation (R2>0.95).The interfering ions experiment showed that the P(AA-AM) hydrogel had good selective adsorption to Pb2+.
By using potassium sulfate and N,N'-methylenebisacrylamide as initiator and acrosslinker, the poly(acrylate-acrylamide) (P(AA-AM)) hydrogel was optimized through orthogonal test and prepared by aqueous polymerization of sodium acrylate and acrylamide. The results of SEM and XPS experiments indicated that the P(AA-AM) hydrogel had three-dimensional network structure with carboxyl and acylamino residues. The carboxyl and acylamino residues could efficiently interact with heavy metal ions to form chelates. The adsorption isotherm and kinetic behavior of Cu2+, Pb2+, Zn2+ and Cd2+ on P(AA-AM) hydrogel were discussed. And the effects of particle size, the temperature, the pH value and the initial concentration of metal ions in solution on the adsorption capacity were investigated. The results showed that the particle size of the P(AA-AM) hydrogel, the pH value and the adsorption temperature of the solution could influence the adsorption reaction. The maximum absorption amounts of 0.097-0.15 mm P(AA-AM) hydrogel to Cu2+, Pb2+, Zn2+ and Cd2+ were 186, 588, 208 and 403 mg/g, respectively under the optimal conditions such as 35℃ and pH 5. The adsorption kinetic followed the pseudo-second-order kinetic mode (R2>0.98) and the adsorption isotherm fit the Langmuir equation (R2>0.95).The interfering ions experiment showed that the P(AA-AM) hydrogel had good selective adsorption to Pb2+.
2016, 44(5): 716-722
doi: 10.11895/j.issn.0253-3820.150809
Abstract:
Peptidomics is an emerging field branching from proteomincs that targets endogenous peptides of a whole organism or a subsystem. Many peptides in body fluids including urine are biomarkers with higher clinical sensitivity and specificity. In this study, we separated and enriched these peptides in human urine by the graphene oxide-lanthanum phosphate composite nanomaterial (LaGM), then identified and analyzed by nano liquid chromatography-high resolution tandem mass spectrometry. In single urine sample, 790 peptides which belong to 123 proteins were identified, and some post-translational modifications including oxidation, phosphorylation, deamidated etc, were also identified. There existed a series of peptide ladders in urine peptidomic. At last, the string analysis on protein level revealed strong interaction among the proteins which the identified peptides belonged. This method can provide support for finding the biomarkers of disease in urine.
Peptidomics is an emerging field branching from proteomincs that targets endogenous peptides of a whole organism or a subsystem. Many peptides in body fluids including urine are biomarkers with higher clinical sensitivity and specificity. In this study, we separated and enriched these peptides in human urine by the graphene oxide-lanthanum phosphate composite nanomaterial (LaGM), then identified and analyzed by nano liquid chromatography-high resolution tandem mass spectrometry. In single urine sample, 790 peptides which belong to 123 proteins were identified, and some post-translational modifications including oxidation, phosphorylation, deamidated etc, were also identified. There existed a series of peptide ladders in urine peptidomic. At last, the string analysis on protein level revealed strong interaction among the proteins which the identified peptides belonged. This method can provide support for finding the biomarkers of disease in urine.
2016, 44(5): 723-730
doi: 10.11895/j.issn.0253-3820.150932
Abstract:
A method for quantifying four urinary metabolites of organophosphorus pesticides using gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The metabolites were extracted and enriched from urine samples with WCX solid phase extraction (SPE) cartridges, followed by liquid-liquid extraction with ethyl acetate-acetonitrile (70:30, V/V). The analytes were chemically derivatized with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide after the derivatives were concentrated by drying and dissolved in phenylmethane. The separation was performed on a HP-5MS capillary column (30 m×0.25 mm×0.25 μm) with temperature programming and the detection was performed in multiple reaction monitoring (MRM) mode using GC-MS/MS. The internal standard method was used for quantification. The extraction solvents, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The result showed that the calibration curves of four metabolites were linear in the range of 0.2-200 μg/L (R2 ≥ 0.992). The limits of detection (LODs) and the limits of quantification (LOQs) of the four metabolites were 0.083-0.667 μg/L and 0.2-2.0 μg/L, respectively. The recoveries of four metabolites ranged from 54.1% to 68.6% (RSD<8.5%, n=6). The established method whichs avoid using large amount of organic solvents in liquid-liquid extraction is stable, reliable and efficient, and is suitable for the analysis of large amounts of samples. Therefore, the method can be applied to assess the exposure level of organophosphorus pesticide in general population.
A method for quantifying four urinary metabolites of organophosphorus pesticides using gas chromatography-tandem mass spectrometry (GC-MS/MS) was developed. The metabolites were extracted and enriched from urine samples with WCX solid phase extraction (SPE) cartridges, followed by liquid-liquid extraction with ethyl acetate-acetonitrile (70:30, V/V). The analytes were chemically derivatized with N-tert-butyldimethylsilyl-N-methyltrifluoroacetamide after the derivatives were concentrated by drying and dissolved in phenylmethane. The separation was performed on a HP-5MS capillary column (30 m×0.25 mm×0.25 μm) with temperature programming and the detection was performed in multiple reaction monitoring (MRM) mode using GC-MS/MS. The internal standard method was used for quantification. The extraction solvents, types of SPE cartridges and eluents were optimized by comparing the sample recoveries under different conditions. The result showed that the calibration curves of four metabolites were linear in the range of 0.2-200 μg/L (R2 ≥ 0.992). The limits of detection (LODs) and the limits of quantification (LOQs) of the four metabolites were 0.083-0.667 μg/L and 0.2-2.0 μg/L, respectively. The recoveries of four metabolites ranged from 54.1% to 68.6% (RSD<8.5%, n=6). The established method whichs avoid using large amount of organic solvents in liquid-liquid extraction is stable, reliable and efficient, and is suitable for the analysis of large amounts of samples. Therefore, the method can be applied to assess the exposure level of organophosphorus pesticide in general population.
2016, 44(5): 731-739
doi: 10.11895/j.issn.0253-3820.150788
Abstract:
A method was developed for the rapid separation and determination of 5 kinds flavonoids (calycosin, calycosin-7-O-β-D-glucoside, ononin, medicarpin and formononetin) in Astragali Radix based on ultra-performance convergence chromatography. After extracting by 80% ethanol, the flavonoids were separated on a Waters Acquity UPC2 CSH (100 mm×3.0 mm i.d., 1.8 μm) column at 40℃ by using supercritical CO2-methanol (contain 0.2% H3PO4) acetonitrile as the mobile phase at a flow rate of 0.4 mL/min, and then analyzed by a UV detector at wavelength of 280 nm, the whole analysis progress was only 15 min. The results showed that the limits of detection (LOD) and the limits of quantitation (LOQ) of five flavonoids were between 0.3 and 0.5 mg/kg, and 1.0 and 2.0 mg/kg, respectively. The spiked recoveries were more than 99.7%, and the relative standard deviations (RSD) were less than 2.2% (n=6). Under the optimal conditions, 13 groups of Astragali Radix from different producing areas were detected. The contents of calycosin, calycosin-7-O-β-D-glucoside, medicarpin, ononin and formononetin were 4.8-102 mg/kg, 14-277 mg/kg, 0-135 mg/kg, and 5.3-119 mg/kg, 2.8-41 mg/kg, respectively. This method is simple, fast, accurate and reproducible, and the result is reliable. The method is applicable for the determination of 5 flavonoids in Astragali Radix.
A method was developed for the rapid separation and determination of 5 kinds flavonoids (calycosin, calycosin-7-O-β-D-glucoside, ononin, medicarpin and formononetin) in Astragali Radix based on ultra-performance convergence chromatography. After extracting by 80% ethanol, the flavonoids were separated on a Waters Acquity UPC2 CSH (100 mm×3.0 mm i.d., 1.8 μm) column at 40℃ by using supercritical CO2-methanol (contain 0.2% H3PO4) acetonitrile as the mobile phase at a flow rate of 0.4 mL/min, and then analyzed by a UV detector at wavelength of 280 nm, the whole analysis progress was only 15 min. The results showed that the limits of detection (LOD) and the limits of quantitation (LOQ) of five flavonoids were between 0.3 and 0.5 mg/kg, and 1.0 and 2.0 mg/kg, respectively. The spiked recoveries were more than 99.7%, and the relative standard deviations (RSD) were less than 2.2% (n=6). Under the optimal conditions, 13 groups of Astragali Radix from different producing areas were detected. The contents of calycosin, calycosin-7-O-β-D-glucoside, medicarpin, ononin and formononetin were 4.8-102 mg/kg, 14-277 mg/kg, 0-135 mg/kg, and 5.3-119 mg/kg, 2.8-41 mg/kg, respectively. This method is simple, fast, accurate and reproducible, and the result is reliable. The method is applicable for the determination of 5 flavonoids in Astragali Radix.
2016, 44(5): 740-746
doi: 10.11895/j.issn.0253-3820.150783
Abstract:
A rapid analytical method was developed for the determination of 4 sterols in atmospheric particles by ultrasonic extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After extraction by methanol and enrichment, sterols were separated on an Atlantis C18 column (100 mm×2.1 mm, 3 μm) with acetonitrile and water served as mobile phase in gradient elution, then determined by HPLC-MS/MS using atmospheric pressure chemical positive ionization (APCI+) and multiple reaction monitoring (MRM). Parameters of chromatography and mass spectrometry, as well as conditions of ultrasonic extraction were optimized. The developed method provided good linearity (R>0.99) and high recoveries (80.3%-97.7%) for 4 sterols. Low detection limits were obtained as 0.015 ng/m3, with RSD less than 15% (n=6). Comparing with GC/MS, this method was more rapid, sensitive and economical because the derivation was eliminated from the procedure, thus saving a lot of resources. Samples of atmospheric particles were detected using this method, and the results indicated that this method could meet the requirements for quantitative analysis of sterols in atmosphere.
A rapid analytical method was developed for the determination of 4 sterols in atmospheric particles by ultrasonic extraction coupled with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). After extraction by methanol and enrichment, sterols were separated on an Atlantis C18 column (100 mm×2.1 mm, 3 μm) with acetonitrile and water served as mobile phase in gradient elution, then determined by HPLC-MS/MS using atmospheric pressure chemical positive ionization (APCI+) and multiple reaction monitoring (MRM). Parameters of chromatography and mass spectrometry, as well as conditions of ultrasonic extraction were optimized. The developed method provided good linearity (R>0.99) and high recoveries (80.3%-97.7%) for 4 sterols. Low detection limits were obtained as 0.015 ng/m3, with RSD less than 15% (n=6). Comparing with GC/MS, this method was more rapid, sensitive and economical because the derivation was eliminated from the procedure, thus saving a lot of resources. Samples of atmospheric particles were detected using this method, and the results indicated that this method could meet the requirements for quantitative analysis of sterols in atmosphere.
2016, 44(5): 747-753
doi: 10.11895/j.issn.0253-3820.150854
Abstract:
Based on sulfonamides inhibited the chemiluminescence (CL) intensities of the system consisting of Ag(Ⅲ) complexes with Luminol (Lu) in basic medium, a method for capillary electrophoresis (CE)-CL separation and determination of sulfamethoxazole (SMZ), sulfadimethoxine (SDM) and sulfathiazole (ST) was established. The three kinds of sulfonamides were separated by capillary electrophoresis, and reacted with Ag(Ⅲ) complexes-Luminol CL system, respectively. In the relative migration time, the relative CL intensity was quantitative and the standard curve method was used to determine the content of the analytes in the sample. The conditions for the separation and chemiluminescence detection system were all optimized. Under the optimized conditions, the linear ranges for the determination of SMZ, SDM and ST were 2.0-200.0 μg/mL (r>0.9977), with detection limits (S/N=3) of 0.33, 0.20 and 0.034 μg/mL, respectively. Relative standard deviation (RSD) values for the peak height were 1.3% to 1.9% (n=7). The proposed method was applied to the determinations of sulfonamides residues in pork, chicken, milk samples with satisfactory results.
Based on sulfonamides inhibited the chemiluminescence (CL) intensities of the system consisting of Ag(Ⅲ) complexes with Luminol (Lu) in basic medium, a method for capillary electrophoresis (CE)-CL separation and determination of sulfamethoxazole (SMZ), sulfadimethoxine (SDM) and sulfathiazole (ST) was established. The three kinds of sulfonamides were separated by capillary electrophoresis, and reacted with Ag(Ⅲ) complexes-Luminol CL system, respectively. In the relative migration time, the relative CL intensity was quantitative and the standard curve method was used to determine the content of the analytes in the sample. The conditions for the separation and chemiluminescence detection system were all optimized. Under the optimized conditions, the linear ranges for the determination of SMZ, SDM and ST were 2.0-200.0 μg/mL (r>0.9977), with detection limits (S/N=3) of 0.33, 0.20 and 0.034 μg/mL, respectively. Relative standard deviation (RSD) values for the peak height were 1.3% to 1.9% (n=7). The proposed method was applied to the determinations of sulfonamides residues in pork, chicken, milk samples with satisfactory results.
2016, 44(5): 754-759
doi: 10.11895/j.issn.0253-3820.150800
Abstract:
Poly (ethylene glycol-ran-propylene glycol) monobutyl ether/phosphate aqueous two-phase system (ATPS) coupled with high performance liquid chromatography (HPLC) was developed for the separation of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) in whey protein isolate (WPI). The main parameters relating to this method were investigated and optimized. The effects of pH value, volume ratio of polymer and KH2PO4 solutions, concentration of NaCl and WPI on the partition of α-LA and β-LG in WPI were investigated. The results showed that efficient separation of both proteins in WPI could be achieved by using the ATPS with 4 mL poly (ethylene glycol-ran-propylene glycol) monobutyl ether solution (40%, m/m) and 4 mL KH2PO4 solution (15.5%, m/m), 0.40 g/10 mL NaCl, while the concentration of WPI was 1 mg/mL, at pH 4.0. Under the optimized conditions, α-LA was separated to the upper phase while β-LG to the bottom phase with the yield of 98.2% and 96.6% respectivelon
Poly (ethylene glycol-ran-propylene glycol) monobutyl ether/phosphate aqueous two-phase system (ATPS) coupled with high performance liquid chromatography (HPLC) was developed for the separation of α-lactalbumin (α-LA) and β-lactoglobulin (β-LG) in whey protein isolate (WPI). The main parameters relating to this method were investigated and optimized. The effects of pH value, volume ratio of polymer and KH2PO4 solutions, concentration of NaCl and WPI on the partition of α-LA and β-LG in WPI were investigated. The results showed that efficient separation of both proteins in WPI could be achieved by using the ATPS with 4 mL poly (ethylene glycol-ran-propylene glycol) monobutyl ether solution (40%, m/m) and 4 mL KH2PO4 solution (15.5%, m/m), 0.40 g/10 mL NaCl, while the concentration of WPI was 1 mg/mL, at pH 4.0. Under the optimized conditions, α-LA was separated to the upper phase while β-LG to the bottom phase with the yield of 98.2% and 96.6% respectivelon
2016, 44(5): 760-766
doi: 10.11895/j.issn.0253-3820.141067
Abstract:
An immunosensor for detection of microcystin-(leucine-arginine) (MCLR) was constructed. Chemical co-precipitation method was used to synthesize ferriferrous oxide magnetic nanoparticles (Fe3O4 MNPs). The Fe3O4 MNPs were modified with 3-aminopropyltriethoxysilane (APTS) and succinic anhydride (SAH) in turn to generate carboxyl-functionalized core-shell MNPs (Fe3O4@APTS·SAH MNPs), which were characterized by transmission electron microscope (TEM), hysteresis loop, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), respectively. The Fe3O4@APTS·SAH MNPs were modified onto the surface of a home-made magnetic glassy carbon electrode (MGCE). Anti-MCLR antibody (anti-MCLR) was immobilized on the modified MGCE by coupling reaction with ethyl-3-(dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Subsequently, bovine serum albumin (BSA) was used to block the non-specific adsorption sites of the electrode. Direct competitive immunoassay format was adopted. In the presence of horseradish peroxidase-conjugated MCLR (MCLR-HRP), MCLR in solution was determined by differential pulse voltammetry (DPV). Under the optimized conditions, MCLR could be detected within a wide linear range of 0.05-100 μg/L with a detection limit of 0.01 μg/L (S/N=3). Moreover, the immunosnssoe exhibited good reproducibility, stability and selectivity. The immunosensor was applied for the determination of MCLR in real water samples with the recoveries from 94.3% to 99.5%.
An immunosensor for detection of microcystin-(leucine-arginine) (MCLR) was constructed. Chemical co-precipitation method was used to synthesize ferriferrous oxide magnetic nanoparticles (Fe3O4 MNPs). The Fe3O4 MNPs were modified with 3-aminopropyltriethoxysilane (APTS) and succinic anhydride (SAH) in turn to generate carboxyl-functionalized core-shell MNPs (Fe3O4@APTS·SAH MNPs), which were characterized by transmission electron microscope (TEM), hysteresis loop, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR), respectively. The Fe3O4@APTS·SAH MNPs were modified onto the surface of a home-made magnetic glassy carbon electrode (MGCE). Anti-MCLR antibody (anti-MCLR) was immobilized on the modified MGCE by coupling reaction with ethyl-3-(dimethyl aminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS). Subsequently, bovine serum albumin (BSA) was used to block the non-specific adsorption sites of the electrode. Direct competitive immunoassay format was adopted. In the presence of horseradish peroxidase-conjugated MCLR (MCLR-HRP), MCLR in solution was determined by differential pulse voltammetry (DPV). Under the optimized conditions, MCLR could be detected within a wide linear range of 0.05-100 μg/L with a detection limit of 0.01 μg/L (S/N=3). Moreover, the immunosnssoe exhibited good reproducibility, stability and selectivity. The immunosensor was applied for the determination of MCLR in real water samples with the recoveries from 94.3% to 99.5%.
2016, 44(5): 767-772
doi: 10.11895/j.issn.0253-3820.150942
Abstract:
Arsenic is a toxic metalloid that is abundant in many marine species, including Antartic krill. Krill oil is being developed for the health-food and dietary supplement because it possesses of omega-3 fatty acids and phospholipid-derived fatty acids; however, it was limited due to its multiple arsenic species residues. Here, we presented a high performance liquid chromatography-inductively coupled plasma mass spectrometric (HPLC-ICP-MS) method for the simultaneous, sensitive, and rapid quantification of five arsenic metabolites including organic and inorganic forms, then the method was applied to the analysis of arsenic species in krill oil. The analytes were separated on a hydroxide-selective anion-exchange column with sodium carbonate (38 mmol/L) and sodium acetate (15 mmol/L) as mobile phase at a flow rate of 0.6 mL/min for 15 min. Arsenic analytes were monitored with a triple quadrupole ICP mass spectrometer. Validation revealed that the method had a linear range from 0.5 to 500 μg/L with R>0.9993. The LOD was 0.1-0.2 μg/L and LOQ was 1.5-2.6 μg/L with RSD<5%. The standard addition method displayed a recovery range from 88.9% to 106.3%. Application of the method to arsenic species analysis in krill oil indicated that krill oil was a safe food or diet supplement.
Arsenic is a toxic metalloid that is abundant in many marine species, including Antartic krill. Krill oil is being developed for the health-food and dietary supplement because it possesses of omega-3 fatty acids and phospholipid-derived fatty acids; however, it was limited due to its multiple arsenic species residues. Here, we presented a high performance liquid chromatography-inductively coupled plasma mass spectrometric (HPLC-ICP-MS) method for the simultaneous, sensitive, and rapid quantification of five arsenic metabolites including organic and inorganic forms, then the method was applied to the analysis of arsenic species in krill oil. The analytes were separated on a hydroxide-selective anion-exchange column with sodium carbonate (38 mmol/L) and sodium acetate (15 mmol/L) as mobile phase at a flow rate of 0.6 mL/min for 15 min. Arsenic analytes were monitored with a triple quadrupole ICP mass spectrometer. Validation revealed that the method had a linear range from 0.5 to 500 μg/L with R>0.9993. The LOD was 0.1-0.2 μg/L and LOQ was 1.5-2.6 μg/L with RSD<5%. The standard addition method displayed a recovery range from 88.9% to 106.3%. Application of the method to arsenic species analysis in krill oil indicated that krill oil was a safe food or diet supplement.
2016, 44(5): 773-778
doi: 10.11895/j.issn.0253-3820.150894
Abstract:
Chromium(Ⅵ) is one of the forbidden heavy metals in the ecological textiles. It is vitally important to develop methods for the sensitive and selective detection of Cr(Ⅵ) in textile samples. In this work, gold nano-particles-sodium alginate clusters (AuNPs-SA) was prepared with sodium alginate in one-step synthesis route and its fluorescent property was investigated. The strongest fluorescence intensity of AuNPs-SA clusters located at the max emission wavelength λem=415 nm under the excitation wavelength of λex=360 nm. A fluorimetric method was developed based on the fluorescent AuNPs-SA nanocomposites selectively quenched in the presence of Cr(Ⅵ). The possible quenching mechanism was discussed on the basis of the interaction of positive AuNPs-SA with negative Cr (Ⅵ). Under the optimized experimental conditions, The ratiometric fluorescence was linearly proportional to the concentration of Cr(Ⅵ) ranging from 1.0×10-8 mol/L to 9.0×10-8 mol/L. The limit of determination (LOD) was estimated at 5.0×10-9 mol/L based on the regression calculations. This method was used for the determination of chromium (Ⅵ) in textile samples, and the obtained result had no significant difference compare to the results based on the National Standard of the People's Republic of China (GB/T 17593.3-2006).
Chromium(Ⅵ) is one of the forbidden heavy metals in the ecological textiles. It is vitally important to develop methods for the sensitive and selective detection of Cr(Ⅵ) in textile samples. In this work, gold nano-particles-sodium alginate clusters (AuNPs-SA) was prepared with sodium alginate in one-step synthesis route and its fluorescent property was investigated. The strongest fluorescence intensity of AuNPs-SA clusters located at the max emission wavelength λem=415 nm under the excitation wavelength of λex=360 nm. A fluorimetric method was developed based on the fluorescent AuNPs-SA nanocomposites selectively quenched in the presence of Cr(Ⅵ). The possible quenching mechanism was discussed on the basis of the interaction of positive AuNPs-SA with negative Cr (Ⅵ). Under the optimized experimental conditions, The ratiometric fluorescence was linearly proportional to the concentration of Cr(Ⅵ) ranging from 1.0×10-8 mol/L to 9.0×10-8 mol/L. The limit of determination (LOD) was estimated at 5.0×10-9 mol/L based on the regression calculations. This method was used for the determination of chromium (Ⅵ) in textile samples, and the obtained result had no significant difference compare to the results based on the National Standard of the People's Republic of China (GB/T 17593.3-2006).
2016, 44(5): 779-786
doi: 10.11895/j.issn.0253-3820.150742
Abstract:
A novel electrochemiluminescence (ECL) DNA biosensor based on nicking endonuclease and the efficient ECL property of quantum dots(QDs) assisted signal amplification was developed. The capture probe DNA(c-DNA) was self-assembled on gold electrode via AuS bond, and then hybridized with target DNA (t-DNA) to form double-stranded DNA. Then nicking endonuclease Nt.BstNBI recognized a cutting site (5'-GAGTC-3') in the double chain and cleaved c-DNA strand at 4 bases away from the 3' end of its recognition site, thus releasing the t-DNA and achieving a recycle of t-DNA in the next hybridization and signal amplification. Finally, carboxyl groups on the surface of CdTe QDs were activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and then reacted with amino groups at the terminal of residual c-DNA on the electrode surface. So the QDs were fabricated and the t-DNA concentration could be determined by measuring the ECL signal of the CdTe QDs. The experimental conditions were optimized and 1 μmol/L c-DNA, 60 min of hybridization time, 0.5 U/μL Nt.BstNBI and 4 h of endonuclease reaction time were chosen. The experimental results showed that under optimal conditions, t-DNA could be specifically assayed with a linear relationship between the ECL signal intensity and the logarithm of t-DNA concentration in the range of 2.0×10-13-2.0×10-11 mol/L, with a limit of detection of 7.3×10-14 mol/L. The biosensor was successfully applied to determine t-DNA concentration in human blood sample with recoveries of 96.4%-108.0%.
A novel electrochemiluminescence (ECL) DNA biosensor based on nicking endonuclease and the efficient ECL property of quantum dots(QDs) assisted signal amplification was developed. The capture probe DNA(c-DNA) was self-assembled on gold electrode via AuS bond, and then hybridized with target DNA (t-DNA) to form double-stranded DNA. Then nicking endonuclease Nt.BstNBI recognized a cutting site (5'-GAGTC-3') in the double chain and cleaved c-DNA strand at 4 bases away from the 3' end of its recognition site, thus releasing the t-DNA and achieving a recycle of t-DNA in the next hybridization and signal amplification. Finally, carboxyl groups on the surface of CdTe QDs were activated with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and N-hydroxysuccinimide (NHS), and then reacted with amino groups at the terminal of residual c-DNA on the electrode surface. So the QDs were fabricated and the t-DNA concentration could be determined by measuring the ECL signal of the CdTe QDs. The experimental conditions were optimized and 1 μmol/L c-DNA, 60 min of hybridization time, 0.5 U/μL Nt.BstNBI and 4 h of endonuclease reaction time were chosen. The experimental results showed that under optimal conditions, t-DNA could be specifically assayed with a linear relationship between the ECL signal intensity and the logarithm of t-DNA concentration in the range of 2.0×10-13-2.0×10-11 mol/L, with a limit of detection of 7.3×10-14 mol/L. The biosensor was successfully applied to determine t-DNA concentration in human blood sample with recoveries of 96.4%-108.0%.
2016, 44(5): 787-791
doi: 10.11895/j.issn.0253-3820.150775
Abstract:
Major cation Mg2+ was presented in enamel as major substituted species. The quantity of Mg and the Mg isotopic ratio in tooth can provide information on the environment, dietary habits, and oral health of individuals. As a result, a method was developed for the determination of Mg isotope based on high-precision multiple collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). The samples were dissolved using a microwave digestion system. Separation of Mg was achieved by cation exchange chromatography of AG50W-X8. The sample solutions were loaded on the resin with 1 mol/L HNO3, the other ions such as Na+ were eluted with 40 mL of HNO3 (1 mol/L), and then the Mg was eluted with 30 mL of HNO3 (1 mol/L), finally the resin was washed with 60 mL of HNO3 (1 mol/L). The Mg isotope was measured using multiple collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). The "sample-standard" bracketing technique was used to correct the instrumental mass bias. The results show that the fast and effective method can be used for the separation, pre-concentration and determination of Mg isotope in calcium-rich tooth samples. Giving values of 26Mg were from -1.38‰ to 4.59‰. The established method for Mg isotope determination provides an important scientific basis for ancient population migration, ancient diet analysis and disease by Mg isotope of ancient human teeth.
Major cation Mg2+ was presented in enamel as major substituted species. The quantity of Mg and the Mg isotopic ratio in tooth can provide information on the environment, dietary habits, and oral health of individuals. As a result, a method was developed for the determination of Mg isotope based on high-precision multiple collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). The samples were dissolved using a microwave digestion system. Separation of Mg was achieved by cation exchange chromatography of AG50W-X8. The sample solutions were loaded on the resin with 1 mol/L HNO3, the other ions such as Na+ were eluted with 40 mL of HNO3 (1 mol/L), and then the Mg was eluted with 30 mL of HNO3 (1 mol/L), finally the resin was washed with 60 mL of HNO3 (1 mol/L). The Mg isotope was measured using multiple collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS). The "sample-standard" bracketing technique was used to correct the instrumental mass bias. The results show that the fast and effective method can be used for the separation, pre-concentration and determination of Mg isotope in calcium-rich tooth samples. Giving values of 26Mg were from -1.38‰ to 4.59‰. The established method for Mg isotope determination provides an important scientific basis for ancient population migration, ancient diet analysis and disease by Mg isotope of ancient human teeth.
2016, 44(5): 792-798
doi: 10.11895/j.issn.0253-3820.150801
Abstract:
To study the accumulation and storage mechanism of heavy metals in earthworms, synchrotron radiation micro X-ray fluorescence (μ-SRXRF) was used to determine element distribution characteristics of K, Ca, Cu, Zn and Pb in earthworms living in garden around Qixiashan lead-zinc mine of Nanjing. The imaging of these elements showed that Pb primarily accumulated in the region around the posterior alimentary canal. There were also Zn and Cu signals in the anterior and posterior part of earthworm, besides the distribution characters of Zn and Cu in the posterior part of earthworm were the same as that of Pb. The findings indicated that the distribution characters in the region around the posterior alimentary canal was a special accumulation and storage mechanism in earthworms for cutting the threat of toxic heavy metals. The high relationship between Pb and Zn distribution indicated that the two elements had a very similar pathway. In this study, we proved that μ-SRXRF had a great advantage in spatial distribution analysis of elements in earthworm samples. A further research focusing on Pb speciation in soil and earthworms is needed for understanding the detoxification mechanism in earthworms under heavy metal stress.
To study the accumulation and storage mechanism of heavy metals in earthworms, synchrotron radiation micro X-ray fluorescence (μ-SRXRF) was used to determine element distribution characteristics of K, Ca, Cu, Zn and Pb in earthworms living in garden around Qixiashan lead-zinc mine of Nanjing. The imaging of these elements showed that Pb primarily accumulated in the region around the posterior alimentary canal. There were also Zn and Cu signals in the anterior and posterior part of earthworm, besides the distribution characters of Zn and Cu in the posterior part of earthworm were the same as that of Pb. The findings indicated that the distribution characters in the region around the posterior alimentary canal was a special accumulation and storage mechanism in earthworms for cutting the threat of toxic heavy metals. The high relationship between Pb and Zn distribution indicated that the two elements had a very similar pathway. In this study, we proved that μ-SRXRF had a great advantage in spatial distribution analysis of elements in earthworm samples. A further research focusing on Pb speciation in soil and earthworms is needed for understanding the detoxification mechanism in earthworms under heavy metal stress.
2016, 44(5): 799-803
doi: 10.11895/j.issn.0253-3820.150601
Abstract:
A fluorescence method for detection of isocarbophos and profenofos was established based on the specific recognition of aptamer. The aptamer recognizing isocarbophos and profenofos was labeled with fluorescent label FAM at 5' end (F-ssDNA). When it bound to complementary DNA chain labeled with quenching group DABCYL at 3' end (Q-ssDNA), the double-stranded structure would be formed and the fluorescence signals became very weak due to the effect of fluorescence resonance energy transfer. While the Q-ssDNA would be released from the double-stranded structure when the aptamer specifically recognized and bound the targets, and the fluorescence signals of the system would recover. Based on this, isocarbophos and profenofos could be quantitatively detected. The optimized experimental conditions were as follows:firstly, 25 nmol/L F-ssDNA and 50 nmol/L Q-ssDNA-2 were incubated for 20 min at 25℃, then an equal volume of pesticide was added and incubated for another 60 min, then the fluorescence intensity of the system was determined. Under the optimal conditions, the change of the fluorescence intensity of the system (ΔI) showed a linear relationship with the isocarbophos or profenofos concentration in the range of 50 to 500 μmol/L. The limit of detection (LOD, σ) was 11.4 μmol/L for isocarbophos with the relative standard deviation (RSD) of 5.8% (n=10). The LOD was 14.0 μmol/L for profenofos with RSD of 4.9% (n=10). The recovery ranged from 85.8% to 95.3% when this method was applied to detect isocarbophos and profenofos in real water samples.
A fluorescence method for detection of isocarbophos and profenofos was established based on the specific recognition of aptamer. The aptamer recognizing isocarbophos and profenofos was labeled with fluorescent label FAM at 5' end (F-ssDNA). When it bound to complementary DNA chain labeled with quenching group DABCYL at 3' end (Q-ssDNA), the double-stranded structure would be formed and the fluorescence signals became very weak due to the effect of fluorescence resonance energy transfer. While the Q-ssDNA would be released from the double-stranded structure when the aptamer specifically recognized and bound the targets, and the fluorescence signals of the system would recover. Based on this, isocarbophos and profenofos could be quantitatively detected. The optimized experimental conditions were as follows:firstly, 25 nmol/L F-ssDNA and 50 nmol/L Q-ssDNA-2 were incubated for 20 min at 25℃, then an equal volume of pesticide was added and incubated for another 60 min, then the fluorescence intensity of the system was determined. Under the optimal conditions, the change of the fluorescence intensity of the system (ΔI) showed a linear relationship with the isocarbophos or profenofos concentration in the range of 50 to 500 μmol/L. The limit of detection (LOD, σ) was 11.4 μmol/L for isocarbophos with the relative standard deviation (RSD) of 5.8% (n=10). The LOD was 14.0 μmol/L for profenofos with RSD of 4.9% (n=10). The recovery ranged from 85.8% to 95.3% when this method was applied to detect isocarbophos and profenofos in real water samples.
2016, 44(5): 804-808
doi: 10.11895/j.issn.0253-3820.150885
Abstract:
The water soluble carbon dots with high stability and excellent photoluminescent properties were synthesized by one-step hydrothermal treatment of glycerol. Based on the significant quenching effect of ferric ion on the fluorescence of carbon dots, a method with high sensitivity and good selectivity for the determination of ferric ion was established. The ratio of fluorescence intensities (F0/F1) had a linear relationship with the concentration of ferric ion in the range of 0.005-1.2 mmol/L (R2=0.995) and the 3-s detection limit was 2.2 μmol/L. Furthermore, the standard deviation and the recovery of the method for determination of iron in Iron tablets were 0.41 mg/tablet and 95.5%-101.0%, respectively. The detection result of this method for Fe3+ ions was in agreement with that 1,10-phenanthroline spectrophotometry.
The water soluble carbon dots with high stability and excellent photoluminescent properties were synthesized by one-step hydrothermal treatment of glycerol. Based on the significant quenching effect of ferric ion on the fluorescence of carbon dots, a method with high sensitivity and good selectivity for the determination of ferric ion was established. The ratio of fluorescence intensities (F0/F1) had a linear relationship with the concentration of ferric ion in the range of 0.005-1.2 mmol/L (R2=0.995) and the 3-s detection limit was 2.2 μmol/L. Furthermore, the standard deviation and the recovery of the method for determination of iron in Iron tablets were 0.41 mg/tablet and 95.5%-101.0%, respectively. The detection result of this method for Fe3+ ions was in agreement with that 1,10-phenanthroline spectrophotometry.
2016, 44(5): 809-815
doi: 10.11895/j.issn.0253-3820.150840
Abstract:
When clay sediments were dissolved by hydrochloric acid, there will form large amounts of water insoluble hydroxide precipitation of Al, Fe and rare earth elements which can absorb boron strongly in high pH solutions. The hydroxide precipitation will greatly affect the extraction of boron and the determination of boron isotope. In this experiment, a new three-step ion-exchange method for the separation and purification of boron was proposed. Firstly, all the Al, Fe and rare earth elements which can generate water insoluble hydroxide, were removed by cation resin column with AG 50 W×8. Next, boron in the sample solutions without Al, Fe and rare earth elements was extracted by boron special resin column with Amberlite IRA 743. Finally, the boron solutions were further purified by anion and cation resin mixed with Ion-exchanger Ⅱand AG 50 W×8. The experimental results showed that the recovery of boron was more than 90% and no obvious boron isotope fractionation could be achieved using this three-step ion-exchange method. Therefore, this method could meet the needs of the high-precision determination of boron isotope of clay sediments.
When clay sediments were dissolved by hydrochloric acid, there will form large amounts of water insoluble hydroxide precipitation of Al, Fe and rare earth elements which can absorb boron strongly in high pH solutions. The hydroxide precipitation will greatly affect the extraction of boron and the determination of boron isotope. In this experiment, a new three-step ion-exchange method for the separation and purification of boron was proposed. Firstly, all the Al, Fe and rare earth elements which can generate water insoluble hydroxide, were removed by cation resin column with AG 50 W×8. Next, boron in the sample solutions without Al, Fe and rare earth elements was extracted by boron special resin column with Amberlite IRA 743. Finally, the boron solutions were further purified by anion and cation resin mixed with Ion-exchanger Ⅱand AG 50 W×8. The experimental results showed that the recovery of boron was more than 90% and no obvious boron isotope fractionation could be achieved using this three-step ion-exchange method. Therefore, this method could meet the needs of the high-precision determination of boron isotope of clay sediments.
2016, 44(5): 816-821
doi: 10.11895/j.issn.0253-3820.150847
Abstract:
A method was developed for the determination of 4-methylimidazole (4-MeI) and 2-methylimidazole (2-MeI) in drinks by surface-enhanced Raman spectroscopy with Au nanoparticle as substrate, and the detection conditions were optimized. Under the optimum conditions, by using sodium sulfate aqueous solution as agglomeration solution, and 250 or 200 μL of Au nanoparticle as substrate, the linear ranges of 4-MeI and 2-MeI were 0.05-5.00 mg/L and 1.0-20.0 mg/L with detection limits of 1.70 μg/L and 0.210 mg/L, respectively. While applied in the determination of 4-MeI and 2-MeI in drink with lift caramel, the concentration of 4-MeI was determined to be 0.093-0.110 mg/L and 2-MeI was not detected. The average recoveries of 4-MeI and 2-MeI were in the range of 80.2%-82.7% and 78.1%-93.5% with relative standard deviations <7.1%. Above all, this method was turned out to be simple, rapid and sensitive, providing a new method for rapid analysis of 4-MeI and 2-MeI in drink with lift caramel.
A method was developed for the determination of 4-methylimidazole (4-MeI) and 2-methylimidazole (2-MeI) in drinks by surface-enhanced Raman spectroscopy with Au nanoparticle as substrate, and the detection conditions were optimized. Under the optimum conditions, by using sodium sulfate aqueous solution as agglomeration solution, and 250 or 200 μL of Au nanoparticle as substrate, the linear ranges of 4-MeI and 2-MeI were 0.05-5.00 mg/L and 1.0-20.0 mg/L with detection limits of 1.70 μg/L and 0.210 mg/L, respectively. While applied in the determination of 4-MeI and 2-MeI in drink with lift caramel, the concentration of 4-MeI was determined to be 0.093-0.110 mg/L and 2-MeI was not detected. The average recoveries of 4-MeI and 2-MeI were in the range of 80.2%-82.7% and 78.1%-93.5% with relative standard deviations <7.1%. Above all, this method was turned out to be simple, rapid and sensitive, providing a new method for rapid analysis of 4-MeI and 2-MeI in drink with lift caramel.
2016, 44(5): 822-827
doi: 10.11895/j.issn.0253-3820.150617
Abstract:
A highly sensitive amperometric glucose biosensor was fabricated by using the synthesized nano-cube copper (Ⅰ) oxide (Cu2O). The synthesized nano-Cu2O and the modified electrode were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM). The results showed that the obtained samples were nano-cube Cu2O. The electrochemical properties of the modified electrode were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). The CV behavior of nano-cube Cu2O modified sensor was examined in 0.1 mol/L PBS (pH 7.4) containing 0.1 mmol/L glucose. The experimental results showed the prepared sensor presented remarkably enhanced electrocatalytic activity towards glucose detection. Linear responses of the sensor to glucose were observed for gulcose concentrations ranging from 5.0×10-6 mol/L to 4.0×10-3 mol/L (r2=0.9983), with a detection limit of 6.8×10-7 mol/L (S/N=3). The CA results showed that the interference from potential interfering species such as uric acid, ascorbic acid, and D fructose could be ignored. In addition, the developed sensor exhibited good repeatability and stability, and was successfully applied to the determination of glucose in real urea samples from diabetics.
A highly sensitive amperometric glucose biosensor was fabricated by using the synthesized nano-cube copper (Ⅰ) oxide (Cu2O). The synthesized nano-Cu2O and the modified electrode were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM). The results showed that the obtained samples were nano-cube Cu2O. The electrochemical properties of the modified electrode were investigated by cyclic voltammetry (CV), differential pulse voltammetry (DPV), electrochemical impedance spectroscopy (EIS), and chronoamperometry (CA). The CV behavior of nano-cube Cu2O modified sensor was examined in 0.1 mol/L PBS (pH 7.4) containing 0.1 mmol/L glucose. The experimental results showed the prepared sensor presented remarkably enhanced electrocatalytic activity towards glucose detection. Linear responses of the sensor to glucose were observed for gulcose concentrations ranging from 5.0×10-6 mol/L to 4.0×10-3 mol/L (r2=0.9983), with a detection limit of 6.8×10-7 mol/L (S/N=3). The CA results showed that the interference from potential interfering species such as uric acid, ascorbic acid, and D fructose could be ignored. In addition, the developed sensor exhibited good repeatability and stability, and was successfully applied to the determination of glucose in real urea samples from diabetics.
2016, 44(5): 828-832
doi: 10.11895/j.issn.0253-3820.150780
Abstract:
An online Two-dimensional column switching ultra performance liquid chromatography (2D-UPLC) method was established for simultaneous quantification of morroniside, loganin, peoniflorin, paeonol in Mingmudihuang Pill. The first-dimensional column was Thermo Accucore XL C18 (250 mm×2.1 mm, 4 μm) while the second-dimensional column was DIONEX Acclaim phenyl-1 (150 mm×4.6 mm, 3 μm). Acetonitrile and water were used as mobile phase with a gradient elution in the first-dimensional analysis and the second-dimensional analysis used acetonitrile-water as mobile phase with a isocratic elution. The valve switching time was 14.5 min, the detection wavelength was set at 240 nm in 0-14.5 min and 275 nm in 14.5-30 min. The flow rate was 0.5 mL/min, and the column temperature was 30℃. The determination of four compounds in Mingmudihuang Pill was completed in 30 min and it could effectually segregate the isomer of morroniside. The linear ranges of morroniside, loganin, peoniflorin and paeonol were 7.6-377 mg/L, 9.2-459 mg/L, 8.4-419 mg/L and 8.2-409 mg/L, respectively, and all the correlation coefficients (r) were>0.9999. The recoveries of the four compounds were 98.3%-100.2%. It was proved that this method could greatly improve the sufficiency of sample analysis and could control the quality of Mingmudihaung Pill efficiently.
An online Two-dimensional column switching ultra performance liquid chromatography (2D-UPLC) method was established for simultaneous quantification of morroniside, loganin, peoniflorin, paeonol in Mingmudihuang Pill. The first-dimensional column was Thermo Accucore XL C18 (250 mm×2.1 mm, 4 μm) while the second-dimensional column was DIONEX Acclaim phenyl-1 (150 mm×4.6 mm, 3 μm). Acetonitrile and water were used as mobile phase with a gradient elution in the first-dimensional analysis and the second-dimensional analysis used acetonitrile-water as mobile phase with a isocratic elution. The valve switching time was 14.5 min, the detection wavelength was set at 240 nm in 0-14.5 min and 275 nm in 14.5-30 min. The flow rate was 0.5 mL/min, and the column temperature was 30℃. The determination of four compounds in Mingmudihuang Pill was completed in 30 min and it could effectually segregate the isomer of morroniside. The linear ranges of morroniside, loganin, peoniflorin and paeonol were 7.6-377 mg/L, 9.2-459 mg/L, 8.4-419 mg/L and 8.2-409 mg/L, respectively, and all the correlation coefficients (r) were>0.9999. The recoveries of the four compounds were 98.3%-100.2%. It was proved that this method could greatly improve the sufficiency of sample analysis and could control the quality of Mingmudihaung Pill efficiently.
