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2016 Volume 44 Issue 6
2016, 44(6): 835-841
doi: 10.11895/j.issn.0253-3820.150945
Abstract:
Graphene oxide (GO) modified stationary phase for open tubular capillary (3 m × 25 μm i.d.) of liquid chromatography (OT-CLC) was fabricated by coating GO sheets onto poly(vinylbenzyl chloride-divinylbenzene) porous composite layer via covalent coupling, which was prepared by in-situ polymerization. Scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM) were used to characterize the structure of the stationary phase. The results demonstrated that poly(vinylbenzyl chloride-divinylbenzene) porous composite layer had decentralized globular structure, and the GO sheets covered on the porous layer homogenously. The phase ratio and sample capacity were greatly improved due to the spherical polymer layer and the coverage of GO. Thus, alkyl benzenes, neutral polycyclic aromatic hydrocarbons, acidic and basic compounds could be well separated by using acetonitrile-water as eluent, while four nucleobases were completely separated by using acetonitrile-0.02 mol/L ammonium acetate as mobile phase. The run-to-run, day-to-day, and column-to-column reproducibilities were evaluated by calculating the relative standard deviations (RSDs, n=6) of the retention time of o-phenylenediamine, aniline and 2, 4, 6-trifluoroaniline, respectively. These RSD values were all in the range of 0.3%-2.0%.
Graphene oxide (GO) modified stationary phase for open tubular capillary (3 m × 25 μm i.d.) of liquid chromatography (OT-CLC) was fabricated by coating GO sheets onto poly(vinylbenzyl chloride-divinylbenzene) porous composite layer via covalent coupling, which was prepared by in-situ polymerization. Scanning electron microscopy (SEM), Raman spectroscopy and transmission electron microscopy (TEM) were used to characterize the structure of the stationary phase. The results demonstrated that poly(vinylbenzyl chloride-divinylbenzene) porous composite layer had decentralized globular structure, and the GO sheets covered on the porous layer homogenously. The phase ratio and sample capacity were greatly improved due to the spherical polymer layer and the coverage of GO. Thus, alkyl benzenes, neutral polycyclic aromatic hydrocarbons, acidic and basic compounds could be well separated by using acetonitrile-water as eluent, while four nucleobases were completely separated by using acetonitrile-0.02 mol/L ammonium acetate as mobile phase. The run-to-run, day-to-day, and column-to-column reproducibilities were evaluated by calculating the relative standard deviations (RSDs, n=6) of the retention time of o-phenylenediamine, aniline and 2, 4, 6-trifluoroaniline, respectively. These RSD values were all in the range of 0.3%-2.0%.
2016, 44(6): 842-849
doi: 10.11895/j.issn.0253-3820.150951
Abstract:
A polyimide coated stir bar for sorptive extraction (SBSE) was prepared by immersion precipitation method, and evaluated by using 5 phenols and chlorinated phenols as model samples. The extraction efficiency of the prepared stir bar was the highest compared with commercial extraction phases of SBSE. Experimental parameters including stir speed, ionic strength, extraction temperature, extraction time, desorption temperature and time were optimized. Under the optimal conditions such as 100 mL of sample, 30 g of NaCl, extraction time of 30 min, stirring speed of 800 r/min and at 25℃, the target compounds were recovered by thermal desorption at 300℃ for 4 min, more than two orders of magnitude of linearity was obtained (R≥0.9995), LOQs (S/N=10) were 0.028-0.123 μg/L, and RSDs were in the range of 1.6%-9.7%. The polyimide SBSE coupled with gas chromatography-mass spectrometry was applied to the extraction/enrichment and analysis of phenols in real samples, including tap water, sea water, and waste water. It was found that the polyimide SBSE showed high selectivity towards polar compounds and high thermostability up to 350℃.
A polyimide coated stir bar for sorptive extraction (SBSE) was prepared by immersion precipitation method, and evaluated by using 5 phenols and chlorinated phenols as model samples. The extraction efficiency of the prepared stir bar was the highest compared with commercial extraction phases of SBSE. Experimental parameters including stir speed, ionic strength, extraction temperature, extraction time, desorption temperature and time were optimized. Under the optimal conditions such as 100 mL of sample, 30 g of NaCl, extraction time of 30 min, stirring speed of 800 r/min and at 25℃, the target compounds were recovered by thermal desorption at 300℃ for 4 min, more than two orders of magnitude of linearity was obtained (R≥0.9995), LOQs (S/N=10) were 0.028-0.123 μg/L, and RSDs were in the range of 1.6%-9.7%. The polyimide SBSE coupled with gas chromatography-mass spectrometry was applied to the extraction/enrichment and analysis of phenols in real samples, including tap water, sea water, and waste water. It was found that the polyimide SBSE showed high selectivity towards polar compounds and high thermostability up to 350℃.
2016, 44(6): 850-856
doi: 10.11895/j.issn.0253-3820.151011
Abstract:
Interferon stimulated gene 15 kDa protein (ISG15) is the first ubiquitin-like protein identified, which plays vital roles in a variety of fields including viral infection and immunological regulation. In this study, liquid chromatography-tandem mass spectrometry was used to analyze ISG15-modified proteins in A549 cells in response to infection by influenza virus, which was enriched by immunoprecipitation. A total of 22 cellular host proteins were identified in A549 cells infected by influenza virus, including ubiquitin-like ISG15 protein, cyclin-T1, heat shock protein 71 kDa, caldesmon, eukaryotic translation initiation factor, and so on. Besides, non-structural protein (NS1) from influenza virus was also identified. Among the 22 host proteins identified, 6 proteins were also identified in the control non-infected A549 cells, including annexin A1, fructose-bisphosphate aldolase A, ATP synthase subunit g, enolase, actin, and tubulin. Bioinformatics analysis revealed that the identified ISG15-modified host proteins induced by influenza virus infection could be classified into 9 protein classes: chaperone, oxidoreductase, enzyme modulator, transferase, nucleic acid binding, transcription factor, kinase, cytoskeletal protein, and structural protein. This study provided a specific and effective tool for analyzing ISG15-modified proteins in proteome level.
Interferon stimulated gene 15 kDa protein (ISG15) is the first ubiquitin-like protein identified, which plays vital roles in a variety of fields including viral infection and immunological regulation. In this study, liquid chromatography-tandem mass spectrometry was used to analyze ISG15-modified proteins in A549 cells in response to infection by influenza virus, which was enriched by immunoprecipitation. A total of 22 cellular host proteins were identified in A549 cells infected by influenza virus, including ubiquitin-like ISG15 protein, cyclin-T1, heat shock protein 71 kDa, caldesmon, eukaryotic translation initiation factor, and so on. Besides, non-structural protein (NS1) from influenza virus was also identified. Among the 22 host proteins identified, 6 proteins were also identified in the control non-infected A549 cells, including annexin A1, fructose-bisphosphate aldolase A, ATP synthase subunit g, enolase, actin, and tubulin. Bioinformatics analysis revealed that the identified ISG15-modified host proteins induced by influenza virus infection could be classified into 9 protein classes: chaperone, oxidoreductase, enzyme modulator, transferase, nucleic acid binding, transcription factor, kinase, cytoskeletal protein, and structural protein. This study provided a specific and effective tool for analyzing ISG15-modified proteins in proteome level.
2016, 44(6): 857-963
doi: 10.11895/j.issn.0253-3820.150934
Abstract:
Wistar rats were intragastrically administered with different doses (2, 5 and 10 g/kg body weight) of haematitum. 1H NMR-based metabonomic analysis coupled with multivariate statistical analysis (principal component analysis and partial least squares-discriminant analysis) was used to analyze the metabolic profiles of the urine samples collected from the treated rats. Univariate analysis on the 1H NMR spectra of urine (1 d before administration, 1-5 d post administration) was used to screen out the potential features of haematitum. Significant treatment related changes were observed for the levels of citrate, tuarine, creatinine, α-ketoglutarate, succinate and dimethylglycine, which could be used as potential features of haematitum. A trend of recovery in connection with dose levels was observed overtime. Such biochemical changes indicated that haematitum treatment at the dose of 2, 5 and 10 g/kg body weight affected the Krebs cycle and glucose metabolism, energy metabolism, choline metabolism and dimethylglycine metabolism in rats. These changes may attribute to the disturbances of hepatic function in 10 g/kg body weight group.
Wistar rats were intragastrically administered with different doses (2, 5 and 10 g/kg body weight) of haematitum. 1H NMR-based metabonomic analysis coupled with multivariate statistical analysis (principal component analysis and partial least squares-discriminant analysis) was used to analyze the metabolic profiles of the urine samples collected from the treated rats. Univariate analysis on the 1H NMR spectra of urine (1 d before administration, 1-5 d post administration) was used to screen out the potential features of haematitum. Significant treatment related changes were observed for the levels of citrate, tuarine, creatinine, α-ketoglutarate, succinate and dimethylglycine, which could be used as potential features of haematitum. A trend of recovery in connection with dose levels was observed overtime. Such biochemical changes indicated that haematitum treatment at the dose of 2, 5 and 10 g/kg body weight affected the Krebs cycle and glucose metabolism, energy metabolism, choline metabolism and dimethylglycine metabolism in rats. These changes may attribute to the disturbances of hepatic function in 10 g/kg body weight group.
2016, 44(6): 864-869
doi: 10.11895/j.issn.0253-3820.150895
Abstract:
A method for rapid determination of semicarbazide in water by hydrophilic interaction chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry was developed. The sample was extracted with acetonitrile after 0.1 mol/L NaOH was added in the sample and then excessive amounts of Na2SO4 was added to stratify acetonitrile from the mix solution. The acetonitrile extraction solution was dehydrated with anhydrous sodium sulfate. The preparation was separated by an amide column using as hydrophilic interaction column, and gradient elution program was employed by using water and acetonitrile containing 0.1% formic acid as mobile phase, then it was detected in positive and selected ion monitoring mode by a quadrupole/electrostatic field orbitrap high resolution mass spectrometry. Internal standard method was used for quantitative analysis. The linear correlation coefficient of semicarbazide was 0.997 in the concentration range of 0.2-20 μg/L under the optimal conditions. The limit of detection was 0.09 μg/L, while the limit of quantitation was 0.30 μg/L. The recoveries were 82.3% to 92.0%, and the relatively standard deviations were less than 7.6% at the spiked levels of 0.5, 1.0 and 5.0 μg/L using river water and sea water as blank samples. The developed method is suitable for the analysis of trace semicarbazide in environment water samples.
A method for rapid determination of semicarbazide in water by hydrophilic interaction chromatography-quadrupole/electrostatic field orbitrap high resolution mass spectrometry was developed. The sample was extracted with acetonitrile after 0.1 mol/L NaOH was added in the sample and then excessive amounts of Na2SO4 was added to stratify acetonitrile from the mix solution. The acetonitrile extraction solution was dehydrated with anhydrous sodium sulfate. The preparation was separated by an amide column using as hydrophilic interaction column, and gradient elution program was employed by using water and acetonitrile containing 0.1% formic acid as mobile phase, then it was detected in positive and selected ion monitoring mode by a quadrupole/electrostatic field orbitrap high resolution mass spectrometry. Internal standard method was used for quantitative analysis. The linear correlation coefficient of semicarbazide was 0.997 in the concentration range of 0.2-20 μg/L under the optimal conditions. The limit of detection was 0.09 μg/L, while the limit of quantitation was 0.30 μg/L. The recoveries were 82.3% to 92.0%, and the relatively standard deviations were less than 7.6% at the spiked levels of 0.5, 1.0 and 5.0 μg/L using river water and sea water as blank samples. The developed method is suitable for the analysis of trace semicarbazide in environment water samples.
2016, 44(6): 870-875
doi: 10.11895/j.issn.0253-3820.150838
Abstract:
A new method for the determination of peptide antibiotics in sediment from aquaculture environment by high performance liquid chromatography-tandem mass spectrometry was developed. The target analytes in sediments were ultrasonically extracted twice with citrate buffer solution and methol mixture (3:4, V/V), followed by complexation with 0.5 g of Na2EDTA, purification with 5 mL of methyl isobutyl ketone, and clean-up with HLB-SPE column. The analytes were separated on a MGII C18 column by gradient elution with 0.1% formaic acid-0.1% formaic acid acetonitrile as mobile phase, detected in multiple reaction monitoring (MRM) with electrospray ionization (ESI) under positive ion mode, and quantified by external standard method. The calibration curves were linear (R2>0.999) over a concentration range of 10-10000 μg/L for colistin and bacitracin and 4-4000 μg/L for virginiamycin M1. The limits of detection (S/N＝3) were 5 μg/kg for colistin and bacitracin and 2 μg/kg for virginiamycin M1. The limits of quantification (S/N＝10) was 10 μg/kg for colistin and bacitracin and 4 μg/kg for virginiamycin M1. At three spiked levels, the recoveries ranged from 79.7% to 91.6% (RSD=1.9%-10.8%), showing high sensitivity, good reproducibility and wide applicability.
A new method for the determination of peptide antibiotics in sediment from aquaculture environment by high performance liquid chromatography-tandem mass spectrometry was developed. The target analytes in sediments were ultrasonically extracted twice with citrate buffer solution and methol mixture (3:4, V/V), followed by complexation with 0.5 g of Na2EDTA, purification with 5 mL of methyl isobutyl ketone, and clean-up with HLB-SPE column. The analytes were separated on a MGII C18 column by gradient elution with 0.1% formaic acid-0.1% formaic acid acetonitrile as mobile phase, detected in multiple reaction monitoring (MRM) with electrospray ionization (ESI) under positive ion mode, and quantified by external standard method. The calibration curves were linear (R2>0.999) over a concentration range of 10-10000 μg/L for colistin and bacitracin and 4-4000 μg/L for virginiamycin M1. The limits of detection (S/N＝3) were 5 μg/kg for colistin and bacitracin and 2 μg/kg for virginiamycin M1. The limits of quantification (S/N＝10) was 10 μg/kg for colistin and bacitracin and 4 μg/kg for virginiamycin M1. At three spiked levels, the recoveries ranged from 79.7% to 91.6% (RSD=1.9%-10.8%), showing high sensitivity, good reproducibility and wide applicability.
2016, 44(6): 876-881
doi: 10.11895/j.issn.0253-3820.150851
Abstract:
In order to evaluate the pharmacokinetic profile of cefotiam hexetil hydrochloride tablet in Chinese healthy volunteers, a sensitive, specific and rapid "protein precipitation-liquid chromatography-tandem mass spectrometry" method was developed and validated in human plasma. Chromatographic separation was achieved on a Waters Symmtry-C18 column (50 mm ×4.6 mm, 5 μm), using a gradient mobile phase consisting of methanol and 1 mmol/L ammonium acetate in water at a flow rate of 1.0 mL/min. Cefotiam and diazepam (internal standard) were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The calibration curve was linear from 5.0 ng/mL to 5000 ng/mL (r>0.99) with limit of quantitation of 5.0 ng/mL. The assay met the published acceptance criteria. This rapid, sensitive and reproducible method was successfully applied to the pharmacokinetic study of cefotiam hexetil hydrochloride tablet in healthy Chinese volunteers and therefore provided a considerable mirror for quantification of other cephalosporins in human matrix.
In order to evaluate the pharmacokinetic profile of cefotiam hexetil hydrochloride tablet in Chinese healthy volunteers, a sensitive, specific and rapid "protein precipitation-liquid chromatography-tandem mass spectrometry" method was developed and validated in human plasma. Chromatographic separation was achieved on a Waters Symmtry-C18 column (50 mm ×4.6 mm, 5 μm), using a gradient mobile phase consisting of methanol and 1 mmol/L ammonium acetate in water at a flow rate of 1.0 mL/min. Cefotiam and diazepam (internal standard) were detected without interference in the multiple reaction monitoring (MRM) mode with positive electrospray ionization. The calibration curve was linear from 5.0 ng/mL to 5000 ng/mL (r>0.99) with limit of quantitation of 5.0 ng/mL. The assay met the published acceptance criteria. This rapid, sensitive and reproducible method was successfully applied to the pharmacokinetic study of cefotiam hexetil hydrochloride tablet in healthy Chinese volunteers and therefore provided a considerable mirror for quantification of other cephalosporins in human matrix.
2016, 44(6): 882-887
doi: 10.11895/j.issn.0253-3820.150853
Abstract:
A highly stable multilayer film modified glassy carbon electrode (GCE) containing polydopamine (PDA) and Cu microparticles was fabricated by layer-by-layer self-assembly technique. The fabrication process was based on the self-polymerization of dopamine and electroless deposition of Cu microparticles on PDA coating. The fabrication process of multilayer films was characterized by UV-Vis spectra. The electrochemical performance of GCE/(PDA/Cu)n modified electrode for glucose detection was investigated by cyclic voltammetry and amperometric current-time curve under alkaline conditions. At detection potential of 0.35 V, the GCE/(PDA/Cu)4 modified electrode presented a linear range of 0.5-9.0 mmol/L with a detection limit of 5.8 μmol/L (S/N=3). Moreover, the sensitivity of the modified electrode was tunable by controlling the number of bilayers of the multilayer films. The modified electrode showed highly selective, stable and fast amperometric sensing of glucose. It was applied to determine glucose in human blood serum with satisfactory results.
A highly stable multilayer film modified glassy carbon electrode (GCE) containing polydopamine (PDA) and Cu microparticles was fabricated by layer-by-layer self-assembly technique. The fabrication process was based on the self-polymerization of dopamine and electroless deposition of Cu microparticles on PDA coating. The fabrication process of multilayer films was characterized by UV-Vis spectra. The electrochemical performance of GCE/(PDA/Cu)n modified electrode for glucose detection was investigated by cyclic voltammetry and amperometric current-time curve under alkaline conditions. At detection potential of 0.35 V, the GCE/(PDA/Cu)4 modified electrode presented a linear range of 0.5-9.0 mmol/L with a detection limit of 5.8 μmol/L (S/N=3). Moreover, the sensitivity of the modified electrode was tunable by controlling the number of bilayers of the multilayer films. The modified electrode showed highly selective, stable and fast amperometric sensing of glucose. It was applied to determine glucose in human blood serum with satisfactory results.
2016, 44(6): 888-892
doi: 10.11895/j.issn.0253-3820.150314
Abstract:
A new strategy for constructing electrochemical aptasensor for lead ion (Pb2+) analysis with extremely high sensitivity was proposed based on the formation of G-quadruplex (G4) when Pb2+ reacting with G-rich aptamers, and the gate-controlled effect was achieved through the controllable channels of probe. SH-β-cyclodextrins were firstly self-assembled on the surface of gold electrode to form an ordered monomolecular layer containing interspaces among β-CD units. When the G-rich aptamer was linked to the self-assembled β-CD and the sensor was immersed into the Pb2+ solution, the aptamers would combine with Pb2+ and then form G-quadruplex structures, which would cover the interspaces and then block the channels for probe entrance. The whole process reduced the oxidative current of probe, which provided a fundamental basis of Pb2+ determination in a quantitative way. Gate-controlled effect enhanced signal-to-noise ratio as well as sensitivity simultaneously. The differential pulse voltammetry response current showed a good linear relationship with the negative logarithm of Pb2+ concentration in the range from 1×10-13 mol/L to 5×10-11 mol/L, with a detection limit of 3.6×10-14 mol/L(DL=3δb/K). The aptasensor was successfully applied to the detection of Pb2+ in real water samples with recoveries of 97.5%-103.3%.
A new strategy for constructing electrochemical aptasensor for lead ion (Pb2+) analysis with extremely high sensitivity was proposed based on the formation of G-quadruplex (G4) when Pb2+ reacting with G-rich aptamers, and the gate-controlled effect was achieved through the controllable channels of probe. SH-β-cyclodextrins were firstly self-assembled on the surface of gold electrode to form an ordered monomolecular layer containing interspaces among β-CD units. When the G-rich aptamer was linked to the self-assembled β-CD and the sensor was immersed into the Pb2+ solution, the aptamers would combine with Pb2+ and then form G-quadruplex structures, which would cover the interspaces and then block the channels for probe entrance. The whole process reduced the oxidative current of probe, which provided a fundamental basis of Pb2+ determination in a quantitative way. Gate-controlled effect enhanced signal-to-noise ratio as well as sensitivity simultaneously. The differential pulse voltammetry response current showed a good linear relationship with the negative logarithm of Pb2+ concentration in the range from 1×10-13 mol/L to 5×10-11 mol/L, with a detection limit of 3.6×10-14 mol/L(DL=3δb/K). The aptasensor was successfully applied to the detection of Pb2+ in real water samples with recoveries of 97.5%-103.3%.
2016, 44(6): 893-900
doi: 10.11895/j.issn.0253-3820.150718
Abstract:
A method was established for the simultaneous determination of the total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry combined with isotope dilution technology. The samples were hydrolyzed with sodium methylate-methanol, and then purified by diatomite cartridge. After being derivatized with heptafluorobutyrylimidazole (HFBI), the target analytes were determined by GC-MS with the deuteriumchloropropanols esters as the internal standards. An excellent linear correlation in the range of 0.050-2.000 mg/L was acquired for 3-monochloropropane-1,2-diol (3-MCPD) esters, 2-MCPD esters, dichloropropan-2-ol (1,3-DCP) esters and 2,3-dichloropropan-1-ol (2,3-DCP) esters, with all the correlation coefficients (r) higher than 0.9995. The limits of detection (LODs) for 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters were 0.015, 0.015, 0.030, and 0.030 mg/kg, respectively, and the limits of quantitation (LOQ) were 0.050, 0.050, 0.100, and 0.100 mg/kg, respectively. The average spike recoveries of the four kinds of chloropropanols esters in blank extra virgin olive oil matrix were typically in a range of 87.0%-110.5% with the relative standard deviations (RSDs) less than 10.1%. The detection rates of 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters in 74 edible oil samples were 94.6%, 63.5%, 5.4%, and 0%, respectively. The contamination levels of 3-MCPD esters, 2-MCPD esters and 1,3-DCP esters were in the range of not detected (ND) to 10.646 mg/kg, ND to 3.617 mg/kg and ND to 0.089 mg/kg, respectively. This method is accurate and rugged for the simultaneous determination of total fatty acid esters of chloropropanols in edible vegetable oils.
A method was established for the simultaneous determination of the total fatty acid esters of chloropropanols in edible oils by gas chromatography-mass spectrometry combined with isotope dilution technology. The samples were hydrolyzed with sodium methylate-methanol, and then purified by diatomite cartridge. After being derivatized with heptafluorobutyrylimidazole (HFBI), the target analytes were determined by GC-MS with the deuteriumchloropropanols esters as the internal standards. An excellent linear correlation in the range of 0.050-2.000 mg/L was acquired for 3-monochloropropane-1,2-diol (3-MCPD) esters, 2-MCPD esters, dichloropropan-2-ol (1,3-DCP) esters and 2,3-dichloropropan-1-ol (2,3-DCP) esters, with all the correlation coefficients (r) higher than 0.9995. The limits of detection (LODs) for 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters were 0.015, 0.015, 0.030, and 0.030 mg/kg, respectively, and the limits of quantitation (LOQ) were 0.050, 0.050, 0.100, and 0.100 mg/kg, respectively. The average spike recoveries of the four kinds of chloropropanols esters in blank extra virgin olive oil matrix were typically in a range of 87.0%-110.5% with the relative standard deviations (RSDs) less than 10.1%. The detection rates of 3-MCPD esters, 2-MCPD esters, 1,3-DCP esters and 2,3-DCP esters in 74 edible oil samples were 94.6%, 63.5%, 5.4%, and 0%, respectively. The contamination levels of 3-MCPD esters, 2-MCPD esters and 1,3-DCP esters were in the range of not detected (ND) to 10.646 mg/kg, ND to 3.617 mg/kg and ND to 0.089 mg/kg, respectively. This method is accurate and rugged for the simultaneous determination of total fatty acid esters of chloropropanols in edible vegetable oils.
2016, 44(6): 901-907
doi: 10.11895/j.issn.0253-3820.150734
Abstract:
A new method for the rapid determination of total phthalates (PAEs) in edible oils was developed. The PAEs in edible oils all were hydrolyzed to phthalic acid with tetrabutylammonium chloride (TBAC) as catalyst. Then phthalic acid was extracted by the supramolecular solvent (SUPRAS) made up of octanol, tetrahydrofuran and aqueous solution, and detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). As a result, hydrolysis time was 10 min. The linear range of phthalic acid was 0.05-2.0 mg/L with a good correlation coefficients (r>0.999). The limits of detection (LOD) and quantification (LOQ) were 5.41 and 18.05 μg/kg, respectively. The recoveries of target analyte at three spiked levels were in the range of 84.6%-104.5%. The repeatability, expressed as relative standard deviation (RSD), was 2.6% for intra-day and 3.7% for inter-day. The total PAEs content of 12 edible oils was found in the range of 0.30-1.09 mg/kg.
A new method for the rapid determination of total phthalates (PAEs) in edible oils was developed. The PAEs in edible oils all were hydrolyzed to phthalic acid with tetrabutylammonium chloride (TBAC) as catalyst. Then phthalic acid was extracted by the supramolecular solvent (SUPRAS) made up of octanol, tetrahydrofuran and aqueous solution, and detected by high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). As a result, hydrolysis time was 10 min. The linear range of phthalic acid was 0.05-2.0 mg/L with a good correlation coefficients (r>0.999). The limits of detection (LOD) and quantification (LOQ) were 5.41 and 18.05 μg/kg, respectively. The recoveries of target analyte at three spiked levels were in the range of 84.6%-104.5%. The repeatability, expressed as relative standard deviation (RSD), was 2.6% for intra-day and 3.7% for inter-day. The total PAEs content of 12 edible oils was found in the range of 0.30-1.09 mg/kg.
2016, 44(6): 908-914
doi: 10.11895/j.issn.0253-3820.160016
Abstract:
A novel magnetic imprinted electrochemical sensor was prepared based on magnetic graphene modified carbon electrode with 4-octylphenol (4-OP) as the template molecule and dopamine as the functional monomer. The morphology of the imprinted sensor based on magnetic graphene was characterized with scanning electron microscopy. The electrochemical performances of the molecularly imprinted sensor were characterized with cyclic voltammetry and differential pulse voltammetry (DPV). The results showed that the imprinted electrochemical sensor had special recognition ability toward 4-OP. The magnetic imprinted electrochemical sensor performance was optimized by using DPV method. The results showed that the response current of the imprinted electrochemical sensor revealed a linear relationship with the negative logarithm of 4-OP concentrations range of 5.0×10-6 -5.0×10-9 mol/L with the detection limit of 3.64×10-10 mol/L (S/N=3). The molecularly imprinted electrochemical sensor was successfully used to detect 4-OP in water samples with the recoveries of 96.0%-104.0%.
A novel magnetic imprinted electrochemical sensor was prepared based on magnetic graphene modified carbon electrode with 4-octylphenol (4-OP) as the template molecule and dopamine as the functional monomer. The morphology of the imprinted sensor based on magnetic graphene was characterized with scanning electron microscopy. The electrochemical performances of the molecularly imprinted sensor were characterized with cyclic voltammetry and differential pulse voltammetry (DPV). The results showed that the imprinted electrochemical sensor had special recognition ability toward 4-OP. The magnetic imprinted electrochemical sensor performance was optimized by using DPV method. The results showed that the response current of the imprinted electrochemical sensor revealed a linear relationship with the negative logarithm of 4-OP concentrations range of 5.0×10-6 -5.0×10-9 mol/L with the detection limit of 3.64×10-10 mol/L (S/N=3). The molecularly imprinted electrochemical sensor was successfully used to detect 4-OP in water samples with the recoveries of 96.0%-104.0%.
2016, 44(6): 915-922
doi: 10.11895/j.issn.0253-3820.150820
Abstract:
The magnetic Illite (MILT) was firstly prepared by an effective polyol-medium solvothermal method. Based on these 3-(methacryloyloxy)propyl trimethoxysilane (MILT-MPS), magnetic molecularly imprinted polymers (MMIPs) were further synthesized via atom transfer radical polymerization in a mixture solution of methanol and deionized water. The as-prepared MMIIPs were characterized by FT-IR, TEM), XRD, TGA and vibrating sample magnetometer (VSM), and the results indicated that the MMIIPs exhibited magnetic sensitivity (Ms=3.866 emu/g), thermal stability and a larger specific surface area (109.58 m2/g). The batch mode adsorption studies were carried out to investigate the recognition specificity and selective capacity. The Langmuir isotherm model was fitted to the equilibrium data, and the monolayer adsorption capacity of MMIPs at 25℃ was 86.58 mg/g. The selective recognition experiments demonstrated high affinity and selectivity of MMIPs towards ciprofloxacin (CIP) over competitive compounds. Combined with high performance liquid chromatographic analysis technology, the prepared MMIIPs were successfully applied to extract and enrich trace CIP in environmental samples with the CIP recoveries from 93.4% to 98.3% and the limit of detection of 0.01 mg/L.
The magnetic Illite (MILT) was firstly prepared by an effective polyol-medium solvothermal method. Based on these 3-(methacryloyloxy)propyl trimethoxysilane (MILT-MPS), magnetic molecularly imprinted polymers (MMIPs) were further synthesized via atom transfer radical polymerization in a mixture solution of methanol and deionized water. The as-prepared MMIIPs were characterized by FT-IR, TEM), XRD, TGA and vibrating sample magnetometer (VSM), and the results indicated that the MMIIPs exhibited magnetic sensitivity (Ms=3.866 emu/g), thermal stability and a larger specific surface area (109.58 m2/g). The batch mode adsorption studies were carried out to investigate the recognition specificity and selective capacity. The Langmuir isotherm model was fitted to the equilibrium data, and the monolayer adsorption capacity of MMIPs at 25℃ was 86.58 mg/g. The selective recognition experiments demonstrated high affinity and selectivity of MMIPs towards ciprofloxacin (CIP) over competitive compounds. Combined with high performance liquid chromatographic analysis technology, the prepared MMIIPs were successfully applied to extract and enrich trace CIP in environmental samples with the CIP recoveries from 93.4% to 98.3% and the limit of detection of 0.01 mg/L.
2016, 44(6): 923-928
doi: 10.11895/j.issn.0253-3820.150925
Abstract:
A rapid and convenient ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method for analysis of ribavirin and its two main kinds of metabolites, 1,2,4-triazole-3-carboxamide (TCONH2) and 1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxylic acid (RTCOOH), in fresh eggs has been developed and validated. The sample was extracted with acetonitrile water (9:1, V/V), added N-hexane to move liposoluble substances, after centrifugation, the upper solvent was cleaned-up by C18 and GCB, then determined by UPLC-MS/MS coupled with Agilent ZORBAX SB-Aq column (100 mm×3.0 mm, 1.8 μm). Over the concentration range of 2.0-200.0 μg/L (0.5-200.0 μg/L and 5.0-200.0 μg/L) for ribavirin (TCONH2 and RTCOOH) in fresh egg matrix, the correlation coefficients (R2) of the calibration curves were above 0.99, and the limits of detection (LODs) were 0.54 μg/L (0.09 and 1.54 μg/L). The limits of quantitation (LOQs) were 1.79, 0.31 and 5.13 μg/L, respectively. At three spiked concentration levels of 5.0, 10.0 and 50.0 μg/L, the recoveries of ribavirin and RTCOOH ranged from 96.1% to 99.6% and 42.9% to 58.3%. And at three spiked concentration levels of 0.5, 2.0 and 5.0 μg/L, the recoveries of TCONH2 ranged from 75.9% to 106.7%. The results of the determination in various real samples showed that the method is simple, accurate, rapid and suitable determination of ribavirin and its two main kinds of metabolites in fresh eggs.
A rapid and convenient ultra high performance liquid chromatography-tandem mass spectrometry(UPLC-MS/MS) method for analysis of ribavirin and its two main kinds of metabolites, 1,2,4-triazole-3-carboxamide (TCONH2) and 1-β-D-ribofuranosyl-1,2,4-triazole-3-carboxylic acid (RTCOOH), in fresh eggs has been developed and validated. The sample was extracted with acetonitrile water (9:1, V/V), added N-hexane to move liposoluble substances, after centrifugation, the upper solvent was cleaned-up by C18 and GCB, then determined by UPLC-MS/MS coupled with Agilent ZORBAX SB-Aq column (100 mm×3.0 mm, 1.8 μm). Over the concentration range of 2.0-200.0 μg/L (0.5-200.0 μg/L and 5.0-200.0 μg/L) for ribavirin (TCONH2 and RTCOOH) in fresh egg matrix, the correlation coefficients (R2) of the calibration curves were above 0.99, and the limits of detection (LODs) were 0.54 μg/L (0.09 and 1.54 μg/L). The limits of quantitation (LOQs) were 1.79, 0.31 and 5.13 μg/L, respectively. At three spiked concentration levels of 5.0, 10.0 and 50.0 μg/L, the recoveries of ribavirin and RTCOOH ranged from 96.1% to 99.6% and 42.9% to 58.3%. And at three spiked concentration levels of 0.5, 2.0 and 5.0 μg/L, the recoveries of TCONH2 ranged from 75.9% to 106.7%. The results of the determination in various real samples showed that the method is simple, accurate, rapid and suitable determination of ribavirin and its two main kinds of metabolites in fresh eggs.
2016, 44(6): 929-934
doi: 10.11895/j.issn.0253-3820.150876
Abstract:
A new approach based on online coupled liquid chromatography-gas chromatography-mass spectrometry (LC-GC/MS) was developed for the rapid determination of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mainstream cigarette smoke, in which a switching valve was employed to online switching between two-dimensional chromatography. The online LC-GC/MS system used in this study was built by using online gel permeation chromatography-gas chromatography-mass spectrometry except that the micro gel column was replaced by micro alkaline alumina column which was prepared by ourselves before. The NNK in mainstream cigarette smoke was collected by a Cambridge filter pad, then the pad was extracted with dichloromethane, and the extract was quantitatively analyzed by online LC-GC/MS with D4-NNK as an internal standard. Online LC-GC/MS allowed online pretreatment purification, and the sample was subjected to online LC-GC/MS without any prior purification, which reduced human error in analysis process. The injection volume of the present online LC-GC/MS could reach 40 μL, which was 20 times of that of the conventional GC/MS (2.0 μL of injection volume), and thus significantly improved the sensitivity. Under the optimum conditions, good linearity (r=0.9998) was obtained over the range of 1.2-120 ng/mL. The recoveries at three spiked levels ranged from 93.9% to 96.0%, and the limits of detection for qualitative and quantitative detection were 0.25 ng/mL and 0.9 ng/mL, respectively. All the results obtained by the present method are comparable to those of standard method recommend by China National Tobacco Company.
A new approach based on online coupled liquid chromatography-gas chromatography-mass spectrometry (LC-GC/MS) was developed for the rapid determination of 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) in mainstream cigarette smoke, in which a switching valve was employed to online switching between two-dimensional chromatography. The online LC-GC/MS system used in this study was built by using online gel permeation chromatography-gas chromatography-mass spectrometry except that the micro gel column was replaced by micro alkaline alumina column which was prepared by ourselves before. The NNK in mainstream cigarette smoke was collected by a Cambridge filter pad, then the pad was extracted with dichloromethane, and the extract was quantitatively analyzed by online LC-GC/MS with D4-NNK as an internal standard. Online LC-GC/MS allowed online pretreatment purification, and the sample was subjected to online LC-GC/MS without any prior purification, which reduced human error in analysis process. The injection volume of the present online LC-GC/MS could reach 40 μL, which was 20 times of that of the conventional GC/MS (2.0 μL of injection volume), and thus significantly improved the sensitivity. Under the optimum conditions, good linearity (r=0.9998) was obtained over the range of 1.2-120 ng/mL. The recoveries at three spiked levels ranged from 93.9% to 96.0%, and the limits of detection for qualitative and quantitative detection were 0.25 ng/mL and 0.9 ng/mL, respectively. All the results obtained by the present method are comparable to those of standard method recommend by China National Tobacco Company.
2016, 44(6): 935-941
doi: 10.11895/j.issn.0253-3820.150850
Abstract:
A method of direct injection and liquid chromatography coupled with tandem mass spectrometric (LC-MS/MS) was developed for simultaneous determination of 5 aniline compounds including aniline, 3-nitroaniline, 4-nitroaniline, 2,6-dichloro-4-nitroaniline and hexanitrodiphenylamine in drinking water and source water. The samples were filtered using a 0.22-μm polyethersulfone membrane prior to HPLC analysis. Five target compounds were chromatographically separated on an HSS T3 column with gradient elution. Chromatographic data were acquired by tandem mass spectrometric detection in multiple reaction monitoring (MRM) mode, and thus favorable resolutions of all target compounds were achieved within 4 min. Under the optimal analytical conditions, the peak area of each analyte and its concentration had a good correlation within the linear range (R≥0.995). The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.773-1.88 μg/L (S/N=3) and 2.58-6.27 μg/L (S/N=10), respectively. The intra-and inter-day relative standard deviations (RSDs) of the mix standard solution were 0.8%-1.9% and 3.3%-4.9%, respectively. The spiked recoveries of the analytes were 84.1%-105% and the RSDs of the spiked samples were 1.0%-3.1%. This proposed method was applied in the analysis of 35 samples from drinking water, source water and surface water, which indicated that the novel LC-MS／MS method could detect 5 aniline compounds in water without any complicated sample pretreatment in an accurate, sensitive and rapid way, and it also could provide technique support for evaluation of the contamination caused by aniline compounds.
A method of direct injection and liquid chromatography coupled with tandem mass spectrometric (LC-MS/MS) was developed for simultaneous determination of 5 aniline compounds including aniline, 3-nitroaniline, 4-nitroaniline, 2,6-dichloro-4-nitroaniline and hexanitrodiphenylamine in drinking water and source water. The samples were filtered using a 0.22-μm polyethersulfone membrane prior to HPLC analysis. Five target compounds were chromatographically separated on an HSS T3 column with gradient elution. Chromatographic data were acquired by tandem mass spectrometric detection in multiple reaction monitoring (MRM) mode, and thus favorable resolutions of all target compounds were achieved within 4 min. Under the optimal analytical conditions, the peak area of each analyte and its concentration had a good correlation within the linear range (R≥0.995). The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.773-1.88 μg/L (S/N=3) and 2.58-6.27 μg/L (S/N=10), respectively. The intra-and inter-day relative standard deviations (RSDs) of the mix standard solution were 0.8%-1.9% and 3.3%-4.9%, respectively. The spiked recoveries of the analytes were 84.1%-105% and the RSDs of the spiked samples were 1.0%-3.1%. This proposed method was applied in the analysis of 35 samples from drinking water, source water and surface water, which indicated that the novel LC-MS／MS method could detect 5 aniline compounds in water without any complicated sample pretreatment in an accurate, sensitive and rapid way, and it also could provide technique support for evaluation of the contamination caused by aniline compounds.
2016, 44(6): 942-949
doi: 10.11895/j.issn.0253-3820.151010
Abstract:
A benzyl functionalized ionic liquid, 1-benzyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide ([BeMIM][Tf2N]), was synthesized and characterized as an extraction solvent of dispersive liquid-liquid microextraction (DLLME) for enrichment and determination of 5 organophosphorus pesticides (phoxim, fenitrothion, chlorpyrifos, phorate and parathion) and 2 aromatic compounds (chloronaphthalene and anthracene) from environmental water samples by high-performance liquid chromatography (HPLC). [BeMIM][Tf2N] had higher extraction efficiency than 1-octyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide and common organic solvents such as CCl4 and C2Cl4. The extraction was performed using 40 μL of [BeMIM][Tf2N] and 1 mL of methanol as extraction solvent and dispersive solvent respectively with centrifugal time of 5 min. Under the optimal conditions, the method proposed here provided a good linearity for all analytes with correlation coefficients between 0.9994 and 0.9998. The repeatability values, described as intra-day and inter-day relative standard deviations (RSDs) of five replicate experiments at three different concentrations of 10, 40 and 100 μg/L, were 1.1%-4.3% and 0.8%-4.8%, respectively. The limits of detection (LOD) were 0.01 μg/L-1.0 μg/L at a signal-to-noise ratio (S/N) of 3. This developed method was convenient and speedy, and could be employed to detect the analytes in three real environmental water samples with satisfactory relative recovery of 82.7%-118.3% and RSD of 0.7%-5.6%. Introduction of benzyl group into the imidazolium could obviously enhance the extraction efficiecny for analytes due to the π-π interaction between [BeMIM][Tf2N] and analytes. [BeMIM][Tf2N] was a satisfactory extraction solvent with a high enrichment factor of 339 and extraction efficiency of 81.4%. Partition coefficients of all analytes in [BeMIM][Tf2N]-DLLME system were determined and the extraction mechanism was discussed.
A benzyl functionalized ionic liquid, 1-benzyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide ([BeMIM][Tf2N]), was synthesized and characterized as an extraction solvent of dispersive liquid-liquid microextraction (DLLME) for enrichment and determination of 5 organophosphorus pesticides (phoxim, fenitrothion, chlorpyrifos, phorate and parathion) and 2 aromatic compounds (chloronaphthalene and anthracene) from environmental water samples by high-performance liquid chromatography (HPLC). [BeMIM][Tf2N] had higher extraction efficiency than 1-octyl-3-methylimidazolium bis [(trifluoromethyl)sulfonyl]imide and common organic solvents such as CCl4 and C2Cl4. The extraction was performed using 40 μL of [BeMIM][Tf2N] and 1 mL of methanol as extraction solvent and dispersive solvent respectively with centrifugal time of 5 min. Under the optimal conditions, the method proposed here provided a good linearity for all analytes with correlation coefficients between 0.9994 and 0.9998. The repeatability values, described as intra-day and inter-day relative standard deviations (RSDs) of five replicate experiments at three different concentrations of 10, 40 and 100 μg/L, were 1.1%-4.3% and 0.8%-4.8%, respectively. The limits of detection (LOD) were 0.01 μg/L-1.0 μg/L at a signal-to-noise ratio (S/N) of 3. This developed method was convenient and speedy, and could be employed to detect the analytes in three real environmental water samples with satisfactory relative recovery of 82.7%-118.3% and RSD of 0.7%-5.6%. Introduction of benzyl group into the imidazolium could obviously enhance the extraction efficiecny for analytes due to the π-π interaction between [BeMIM][Tf2N] and analytes. [BeMIM][Tf2N] was a satisfactory extraction solvent with a high enrichment factor of 339 and extraction efficiency of 81.4%. Partition coefficients of all analytes in [BeMIM][Tf2N]-DLLME system were determined and the extraction mechanism was discussed.
2016, 44(6): 950-957
doi: 10.11895/j.issn.0253-3820.160012
Abstract:
An enhance matrix removal (EMR) QuEChERS method for simultaneous determination of 22 triazine herbicide residuals such as atrazine, propazine, terbumeton, and desmetryn in corn was established and validated. The corn samples were initially extracted with acetonitrile (MeCN) in high-speed homogenization, and the targeted pesticides were prepared using EMR-Lipid (Enhanced matrix removal-lipid) method to clean-up and EMR-Polish to salt out, separated on a Kinetex XB-C18 with acetonitrile and 0.1% formic acid aqueous as eluant, and then detected by UFLC-MS/MS under positive (ESI+) electrospray ionization and MRM models. The average recoveries of 22 herbicides were in the range of 72%-105% at the spiked level of 5, 10 and 20 μg/kg. The relative standard deviations were less than 15%. In the method validation, correlation coefficients were higher than 0.993 with the linear range from 1.0 μg/L to 50 μg/L. The qualitative analysis and quantitative analysis were investigated by UFLC-MS/MS and matrix-matched calibration curves. The results showed that EMR QuEChERS combined with UFLC-MS/MS purification method was rapid, accurate and sensitive for the determination of 22 triazine herbicides residues in corn.
An enhance matrix removal (EMR) QuEChERS method for simultaneous determination of 22 triazine herbicide residuals such as atrazine, propazine, terbumeton, and desmetryn in corn was established and validated. The corn samples were initially extracted with acetonitrile (MeCN) in high-speed homogenization, and the targeted pesticides were prepared using EMR-Lipid (Enhanced matrix removal-lipid) method to clean-up and EMR-Polish to salt out, separated on a Kinetex XB-C18 with acetonitrile and 0.1% formic acid aqueous as eluant, and then detected by UFLC-MS/MS under positive (ESI+) electrospray ionization and MRM models. The average recoveries of 22 herbicides were in the range of 72%-105% at the spiked level of 5, 10 and 20 μg/kg. The relative standard deviations were less than 15%. In the method validation, correlation coefficients were higher than 0.993 with the linear range from 1.0 μg/L to 50 μg/L. The qualitative analysis and quantitative analysis were investigated by UFLC-MS/MS and matrix-matched calibration curves. The results showed that EMR QuEChERS combined with UFLC-MS/MS purification method was rapid, accurate and sensitive for the determination of 22 triazine herbicides residues in corn.
2016, 44(6): 958-964
doi: 10.11895/j.issn.0253-3820.150997
Abstract:
n-Octanol/water partition coefficients (Kow) is an important parameter commonly used to explain toxicity, activity and transmembrane of drugs. However, it is difficult to be detected by direct experimental determination. In this work, a set of 29 neutral and acidic analogues of naphthalene and anthraquinone with reliable experimental Kow data was chosen as model compounds for establishing linear relationship between the logarithm of apparent n-octanol/water partition coefficient (lgKow"), and the logarithm of reversed phase-high performance liquid chromatography (RP-HPLC) retention factor of the solutes corresponding to neat aqueous fraction of mobile phase (lgkw) as the quantitative structure-retention relationship (QSRR) model. Methanol-water mixture was used as mobile phase at various pH, and retention time (tR) was rectified by a dual-point retention time correction (DP-RTC) in this method. The experiment results indicated that the proposed QSRR model had good correlation coefficient R2=0.974-0.976 with satisfactory results of internal and external validation (the cross-validated correlation coefficient R2cv of 0.970-0.973, and 1.4%≤relative error (RE) ≤7.9% for all the 6 verification compounds). In addition, this QSRR model was compared with linear solvation energy relationship (LSER) involved in different descriptors of molecular structure, showing no differences. The QSRR model was applied to measure Kow of 11 naphthalenes and anthraquinones, and the predicted data were compared with Shake-flask method (SFM) experimental ones, as well as calculated ones obtained by software. The results suggested that the proposed method for Kow determination in this work was more accurate, simple and fast. To the best of our knowledge, this is the first report on measuring Kow data for these compounds. The proposed strategy provides the possibility in determining Kow of lipophilic components in complex mixture more quickly and accurately by RP-HPLC.
n-Octanol/water partition coefficients (Kow) is an important parameter commonly used to explain toxicity, activity and transmembrane of drugs. However, it is difficult to be detected by direct experimental determination. In this work, a set of 29 neutral and acidic analogues of naphthalene and anthraquinone with reliable experimental Kow data was chosen as model compounds for establishing linear relationship between the logarithm of apparent n-octanol/water partition coefficient (lgKow"), and the logarithm of reversed phase-high performance liquid chromatography (RP-HPLC) retention factor of the solutes corresponding to neat aqueous fraction of mobile phase (lgkw) as the quantitative structure-retention relationship (QSRR) model. Methanol-water mixture was used as mobile phase at various pH, and retention time (tR) was rectified by a dual-point retention time correction (DP-RTC) in this method. The experiment results indicated that the proposed QSRR model had good correlation coefficient R2=0.974-0.976 with satisfactory results of internal and external validation (the cross-validated correlation coefficient R2cv of 0.970-0.973, and 1.4%≤relative error (RE) ≤7.9% for all the 6 verification compounds). In addition, this QSRR model was compared with linear solvation energy relationship (LSER) involved in different descriptors of molecular structure, showing no differences. The QSRR model was applied to measure Kow of 11 naphthalenes and anthraquinones, and the predicted data were compared with Shake-flask method (SFM) experimental ones, as well as calculated ones obtained by software. The results suggested that the proposed method for Kow determination in this work was more accurate, simple and fast. To the best of our knowledge, this is the first report on measuring Kow data for these compounds. The proposed strategy provides the possibility in determining Kow of lipophilic components in complex mixture more quickly and accurately by RP-HPLC.
2016, 44(6): 965-969
doi: 10.11895/j.issn.0253-3820.150839
Abstract:
A technique of diffusive gradients in thin films (DGT) was developed for the in situ measurement of reactive phosphorus species in natural waters, sediments and potentially soils. Polyacrylamide/basic magnesium carbonate was used as the novel binding phase of DGT. Various factors, such as initial concentration, deployment time, pH and ionic strength, which may affect the adsorption of phosphate to the DGT were investigated. H2SO4 (0.25 mol/L, 10 mL) was used for elution of phosphate from the binding gel, and an elution efficiency of 85±5% was obtained. The DGT measurement was independent of ionic strength (0.001-0.05 mol/L) and pH (4.10-9.15). The results indicated that the maximum adsorption capacities of DGT were limited to 20.4 μg per disc (T=25℃, pH=7.00, [P]=2 mg/L). Good agreement was obtained between the measurement results of DGT method and molybdenum blue method in the P concentration from 0.001 to 20 mg/L. The method detection limit (MDL) was 102.4 ng/L. Field performances of DGT in synthetic seawater, the coastal seawater of Xiamen, Lake Yihai, Lake Chaohu and Nanfei River indicated that the basic magnesium carbonate-DGT method was more reliable than the commonly used ferrihydrite-DGT method."
A technique of diffusive gradients in thin films (DGT) was developed for the in situ measurement of reactive phosphorus species in natural waters, sediments and potentially soils. Polyacrylamide/basic magnesium carbonate was used as the novel binding phase of DGT. Various factors, such as initial concentration, deployment time, pH and ionic strength, which may affect the adsorption of phosphate to the DGT were investigated. H2SO4 (0.25 mol/L, 10 mL) was used for elution of phosphate from the binding gel, and an elution efficiency of 85±5% was obtained. The DGT measurement was independent of ionic strength (0.001-0.05 mol/L) and pH (4.10-9.15). The results indicated that the maximum adsorption capacities of DGT were limited to 20.4 μg per disc (T=25℃, pH=7.00, [P]=2 mg/L). Good agreement was obtained between the measurement results of DGT method and molybdenum blue method in the P concentration from 0.001 to 20 mg/L. The method detection limit (MDL) was 102.4 ng/L. Field performances of DGT in synthetic seawater, the coastal seawater of Xiamen, Lake Yihai, Lake Chaohu and Nanfei River indicated that the basic magnesium carbonate-DGT method was more reliable than the commonly used ferrihydrite-DGT method."
2016, 44(6): 970-978
doi: 10.11895/j.issn.0253-3820.150229
Abstract:
A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method coupled with an immunoaffinity clean-up column was successfully developed for determination of aflatoxins (AFB1, AFB2, AFG1, AFG2, AFM1 and AFM2) and zeranols (α-zeranol, β-zeranol, α-zearalenol, β-zearalenol, zearalanone and zearalenone ). The sample was extracted with methanol-acetonitrile (20:80, V/V) after enzymatic digestion by β-glucuronidase/sulfatase, and the extraction solution was passed through glassy fiber filter paper and then diluted with phosphate buffer solution (PBS). The reconstituted solution was cleaned up with IAC-AZ immunoaffinity column, and then analyzed by HPLC-MS/MS in multiple reaction monitoring (MRM) mode. The results indicated that the linear detection range was 0.03-6.0 μg/L for AFB2 and AFG2, and 0.05-20 μg/L for the rest compounds. The correlation coefficients were above 0.999. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.01-0.03 μg/kg and 0.04-0.09 μg/kg, respectively. The recoveries of the aflatoxins and zeranols were in the range of 73.6%-98.4% at the spiked levels of 0.5, 1 and 5 μg/kg, and the relative standard deviations (RSDs) were in the range of 1.9%-11.2%. The method was proved to be simple and accurate, and suitable for the rapid determination of aflatoxins and zeranols in animal-originated foods.
A high performance liquid chromatography-tandem mass spectrometric (HPLC-MS/MS) method coupled with an immunoaffinity clean-up column was successfully developed for determination of aflatoxins (AFB1, AFB2, AFG1, AFG2, AFM1 and AFM2) and zeranols (α-zeranol, β-zeranol, α-zearalenol, β-zearalenol, zearalanone and zearalenone ). The sample was extracted with methanol-acetonitrile (20:80, V/V) after enzymatic digestion by β-glucuronidase/sulfatase, and the extraction solution was passed through glassy fiber filter paper and then diluted with phosphate buffer solution (PBS). The reconstituted solution was cleaned up with IAC-AZ immunoaffinity column, and then analyzed by HPLC-MS/MS in multiple reaction monitoring (MRM) mode. The results indicated that the linear detection range was 0.03-6.0 μg/L for AFB2 and AFG2, and 0.05-20 μg/L for the rest compounds. The correlation coefficients were above 0.999. The limits of detection (LOD) and limits of quantitation (LOQ) were 0.01-0.03 μg/kg and 0.04-0.09 μg/kg, respectively. The recoveries of the aflatoxins and zeranols were in the range of 73.6%-98.4% at the spiked levels of 0.5, 1 and 5 μg/kg, and the relative standard deviations (RSDs) were in the range of 1.9%-11.2%. The method was proved to be simple and accurate, and suitable for the rapid determination of aflatoxins and zeranols in animal-originated foods.
2016, 44(6): 979-983
doi: 10.11895/j.issn.0253-3820.150927
Abstract:
Baizi Yangxin tablets are common Chinese medicine used for the treatment of heart palpitations, insomnia and irritable forgetful. To evaluate the total amount of heavy metals evaluation, artificial gastric juice was used as juice samples and the extracted soluble heavy metals were extracted by microwave digestion technology. An analytical method of bionic extraction microwave digestion with inductively coupled plasma mass spectrometry ( ICP-MS ) was established for the determination of trace metals, such as Co, Cr, Cu, Ba, Cd, Mn, Ni, Pb, Hg, Sr and Zn, in 18 batches of Baizi Yangxin tablets. The correlation coefficient of linear regression equation for different elements ranged from 0.9989 to 1.0000, the detection limit was 0.19-5.6 μg/L, and the repeatability of the method was less than 6.2%, the precision of the RSD value was less than 5.6%, and the recovery rate was 87.7%-101.9%. According to the standard of the heavy metal in the standard of import and export of medicinal plants and preparations, the contents of Cd, Cu and Pb in the 18 batches were not exceed the standard, but the Hg content (7.68 mg/kg) exceeded the standard value. The bionic extraction-ICP-MS method provide a reference basis for the safety of the proprietary Chinese medicine's study.
Baizi Yangxin tablets are common Chinese medicine used for the treatment of heart palpitations, insomnia and irritable forgetful. To evaluate the total amount of heavy metals evaluation, artificial gastric juice was used as juice samples and the extracted soluble heavy metals were extracted by microwave digestion technology. An analytical method of bionic extraction microwave digestion with inductively coupled plasma mass spectrometry ( ICP-MS ) was established for the determination of trace metals, such as Co, Cr, Cu, Ba, Cd, Mn, Ni, Pb, Hg, Sr and Zn, in 18 batches of Baizi Yangxin tablets. The correlation coefficient of linear regression equation for different elements ranged from 0.9989 to 1.0000, the detection limit was 0.19-5.6 μg/L, and the repeatability of the method was less than 6.2%, the precision of the RSD value was less than 5.6%, and the recovery rate was 87.7%-101.9%. According to the standard of the heavy metal in the standard of import and export of medicinal plants and preparations, the contents of Cd, Cu and Pb in the 18 batches were not exceed the standard, but the Hg content (7.68 mg/kg) exceeded the standard value. The bionic extraction-ICP-MS method provide a reference basis for the safety of the proprietary Chinese medicine's study.
2016, 44(6): 984-993
doi: 10.11895/j.issn.0253-3820.150971
Abstract:
Phospholipids, the principal constituents of cell membranes, have very important physiological functions and is closely related to human health and diseases. Therefore, comprehensive analysis of phospholipids is essential to enhance our understanding of function of phospholipids in disease process. Phospholipidomics is a phospholipids-targeted metabolomic approach which focuses on comprehensive qualitation and quantitation of phospholipids in biological system. Phospholipidomics study is carried out by the analysis and detection technologies involved in sample preparation, separation, qualitation and quantitation and data mining. In this paper, analysis and detection technologies for phospholipidomics are reviewed, providing a valuable reference for developing fast, stable, reliable, high sensitivity, high resolution, and high throughput platform technologies for phospholipidomics. The integrated investigation of phospholipidomics and other omics are proposed to promote the further development of analytical bioscience.
Phospholipids, the principal constituents of cell membranes, have very important physiological functions and is closely related to human health and diseases. Therefore, comprehensive analysis of phospholipids is essential to enhance our understanding of function of phospholipids in disease process. Phospholipidomics is a phospholipids-targeted metabolomic approach which focuses on comprehensive qualitation and quantitation of phospholipids in biological system. Phospholipidomics study is carried out by the analysis and detection technologies involved in sample preparation, separation, qualitation and quantitation and data mining. In this paper, analysis and detection technologies for phospholipidomics are reviewed, providing a valuable reference for developing fast, stable, reliable, high sensitivity, high resolution, and high throughput platform technologies for phospholipidomics. The integrated investigation of phospholipidomics and other omics are proposed to promote the further development of analytical bioscience.
2016, 44(6): 994-1000
doi: 10.11895/j.issn.0253-3820.151019
Abstract:
Theoretical study and experimental test of a new ion trap mass analyzer-ladder electrode linear ion trap (LeLIT) were reported. The LeLIT was composed of two pairs of ladder electrodes and one pair of end-electrodes. By optimizing the geometric structure of ladder electrodes, we optimized the electric field distribution for optimum mass analysis. Since the distribution of electric field can be controlled by the adjustment of LeLIT structure, LeLIT have better performance than rectilinear ion trap theoretically. Due to its simpler structure than hyperbolic electrode LIT, LeLIT can be easily built. In this work, the height, width and field ratio were adjusted for optimizing the property of LeLIT, and a mass resolution of 10150 was obtained when the mass scan speed was 225 Da/s for a LeLIT with X0×Y0=9 mm×5 mm dimension. The preliminary experimental result showed that the LeLIT has proper tandem mass spectrometric performance as any conventional ion trap mass analyzer.
Theoretical study and experimental test of a new ion trap mass analyzer-ladder electrode linear ion trap (LeLIT) were reported. The LeLIT was composed of two pairs of ladder electrodes and one pair of end-electrodes. By optimizing the geometric structure of ladder electrodes, we optimized the electric field distribution for optimum mass analysis. Since the distribution of electric field can be controlled by the adjustment of LeLIT structure, LeLIT have better performance than rectilinear ion trap theoretically. Due to its simpler structure than hyperbolic electrode LIT, LeLIT can be easily built. In this work, the height, width and field ratio were adjusted for optimizing the property of LeLIT, and a mass resolution of 10150 was obtained when the mass scan speed was 225 Da/s for a LeLIT with X0×Y0=9 mm×5 mm dimension. The preliminary experimental result showed that the LeLIT has proper tandem mass spectrometric performance as any conventional ion trap mass analyzer.
