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2016 Volume 34 Issue 6
2016, 34(6): 545-549
doi: 10.3724/SP.J.1123.2016.02015
Abstract:
The ionic liquids as a new class of green solvent have received the majority attention. In this study, two polymeric ionic liquid monomers were synthesized by one step method, and polymerized by precipitation polymerization method. The resultant materials were characterized by nuclear magnetic resonance spectroscopy (1H NMR), scanning electron microscopy (SEM) and thermo gravimetric analyzer (TGA) methods. The results showed that the morphology of the resultant materials was ellipsoidal particles with the size of about 600 nm. The adsorption properties of the resultant materials for bovine serum albumin (BSA), ovalbumin (OVA), bovine hemoglobin (BHb), lysozyme (Lys) and trypsin (Try) were also evaluated. The two poly(ionic liquid)s materials showed excellent adsorption properties for proteins. The poly(4-vinyl benzyl chloride quaternary ammonium ionic liquid)s material exhibited the best adsorption to trypsin. Such materials show potential in biomedical and material engineering.
The ionic liquids as a new class of green solvent have received the majority attention. In this study, two polymeric ionic liquid monomers were synthesized by one step method, and polymerized by precipitation polymerization method. The resultant materials were characterized by nuclear magnetic resonance spectroscopy (1H NMR), scanning electron microscopy (SEM) and thermo gravimetric analyzer (TGA) methods. The results showed that the morphology of the resultant materials was ellipsoidal particles with the size of about 600 nm. The adsorption properties of the resultant materials for bovine serum albumin (BSA), ovalbumin (OVA), bovine hemoglobin (BHb), lysozyme (Lys) and trypsin (Try) were also evaluated. The two poly(ionic liquid)s materials showed excellent adsorption properties for proteins. The poly(4-vinyl benzyl chloride quaternary ammonium ionic liquid)s material exhibited the best adsorption to trypsin. Such materials show potential in biomedical and material engineering.
2016, 34(6): 550-557
doi: 10.3724/SP.J.1123.2016.03043
Abstract:
Rheumatoid arthritis (RA) is an inflammatory disease leading to joint swollen, pain and even deformity. Cardiovascular disease (CVD) is regarded as a major cause of morbidity in patients. Chronic systemic inflammation in patients is an independent CVD risk factor. Cyclooxygenase-2 (COX-2) inhibitor, a commonly used drug in the treatment of RA, can increase the risk of CVD. Lipid metabolic disorder is highly correlated with the occurrence of CVD, thus we investigated the serum lipid changes caused by RA and drug treatment to help to elucidate the mechanism of CVD in RA. Collagen-induced arthritis (CIA) is employed as a model of RA. After modeling, COX-2 inhibitor-meloxicam was orally administrated for three weeks, and the serum lipid profiles were analyzed by the multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL). Totally 105 lipids were detected in serum, including 35 phosphatidylcholines (PCs), 18 lysophosphatidylcholines (LysoPCs), 15 phosphatidyl inositols (PIs), 3 phosphatidyl glycerols (PGs), 19 sphingomyelins (SMs) and 15 ceramides (Cers). In the principle component analysis, it was observed that the lipid profiles of CIA model rats were very different from those of the control rats, and the COX-2 inhibitor can improve the lipid metabolism partly. Further, ANOVA analysis revealed that 39 of the 105 identified lipids were up-regulated in CIA rats, including 7 PIs, 15 SMs, 5 Cers, 10 PCs and 2 LysoPCs. Most of these lipids were down-regulated under the treatment of COX-2 inhibitor. In addition, the five PCs and one LysoPC were abnormally regulated by the drug. The MDMS-SL discovered lipid disturbance in CIA model rats that might be related to risk factors of atherosclerosis; the COX-2 inhibitor can greatly repair the lipid disorder caused by modeling, while induce abnormal changes of some PCs and LysoPC which may cause side-effect.
Rheumatoid arthritis (RA) is an inflammatory disease leading to joint swollen, pain and even deformity. Cardiovascular disease (CVD) is regarded as a major cause of morbidity in patients. Chronic systemic inflammation in patients is an independent CVD risk factor. Cyclooxygenase-2 (COX-2) inhibitor, a commonly used drug in the treatment of RA, can increase the risk of CVD. Lipid metabolic disorder is highly correlated with the occurrence of CVD, thus we investigated the serum lipid changes caused by RA and drug treatment to help to elucidate the mechanism of CVD in RA. Collagen-induced arthritis (CIA) is employed as a model of RA. After modeling, COX-2 inhibitor-meloxicam was orally administrated for three weeks, and the serum lipid profiles were analyzed by the multi-dimensional mass spectrometry-based shotgun lipidomics (MDMS-SL). Totally 105 lipids were detected in serum, including 35 phosphatidylcholines (PCs), 18 lysophosphatidylcholines (LysoPCs), 15 phosphatidyl inositols (PIs), 3 phosphatidyl glycerols (PGs), 19 sphingomyelins (SMs) and 15 ceramides (Cers). In the principle component analysis, it was observed that the lipid profiles of CIA model rats were very different from those of the control rats, and the COX-2 inhibitor can improve the lipid metabolism partly. Further, ANOVA analysis revealed that 39 of the 105 identified lipids were up-regulated in CIA rats, including 7 PIs, 15 SMs, 5 Cers, 10 PCs and 2 LysoPCs. Most of these lipids were down-regulated under the treatment of COX-2 inhibitor. In addition, the five PCs and one LysoPC were abnormally regulated by the drug. The MDMS-SL discovered lipid disturbance in CIA model rats that might be related to risk factors of atherosclerosis; the COX-2 inhibitor can greatly repair the lipid disorder caused by modeling, while induce abnormal changes of some PCs and LysoPC which may cause side-effect.
2016, 34(6): 558-566
doi: 10.3724/SP.J.1123.2016.01033
Abstract:
The chemical constituents in different tissues (primary cuticula, epidermis, peel, pulp, seed) of the three kinds of pomelo (Shatian pomelo, Guanxi honey pomelo, Yuhuan pomelo) in China were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry, liquid chromatography-electrospray ion trap-mass spectrometry and ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. The results showed that 68 different chemical constituents were identified in the five tissues of the three kinds of pomelo (19 alcohols, 15 esters, 9 olefins, 8 organic acids, 7 ketones, 4 alkanes and 6 other substances). Among which 7 common constituents were found in primary cuticula, and the highest content was 44.03%(limonene). In epidermis, the highest content in 6 common constituents was 44.62%(oleic acid amide). In 10 common constituents of peel, the highest content was 30.75%(sitosterol). The highest content was 20.02% (palmitic acid) of 11 common constituents in pulp. In seed, the highest content of 15 common constituents was 45.83%( α-linoleic acid). We also applied the cluster analysis and similarity analysis to the chemical constituents of different parts of the three kinds of pomelo. It is apparent that there are differences and similarities in species and contents of the constituents in the same parts of different varieties of pomelo. The chromatographic fingerprint specificity is obvious, which is helpful to put forward a new idea of chromatographic fingerprint in classification, quality control and geographical tracing of pomelo.
The chemical constituents in different tissues (primary cuticula, epidermis, peel, pulp, seed) of the three kinds of pomelo (Shatian pomelo, Guanxi honey pomelo, Yuhuan pomelo) in China were qualitatively and quantitatively analyzed by gas chromatography-mass spectrometry, liquid chromatography-electrospray ion trap-mass spectrometry and ultra-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry. The results showed that 68 different chemical constituents were identified in the five tissues of the three kinds of pomelo (19 alcohols, 15 esters, 9 olefins, 8 organic acids, 7 ketones, 4 alkanes and 6 other substances). Among which 7 common constituents were found in primary cuticula, and the highest content was 44.03%(limonene). In epidermis, the highest content in 6 common constituents was 44.62%(oleic acid amide). In 10 common constituents of peel, the highest content was 30.75%(sitosterol). The highest content was 20.02% (palmitic acid) of 11 common constituents in pulp. In seed, the highest content of 15 common constituents was 45.83%( α-linoleic acid). We also applied the cluster analysis and similarity analysis to the chemical constituents of different parts of the three kinds of pomelo. It is apparent that there are differences and similarities in species and contents of the constituents in the same parts of different varieties of pomelo. The chromatographic fingerprint specificity is obvious, which is helpful to put forward a new idea of chromatographic fingerprint in classification, quality control and geographical tracing of pomelo.
2016, 34(6): 567-571
doi: 10.3724/SP.J.1123.2016.02006
Abstract:
A high-throughput method to measure homocysteine (Hcy) in dried blood spots (DBS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established. The DBS sample processing includes adding homocystine-D8 as internal standard, dithiothreitol (DTT) as reducing agent for bound Hcy forms, acetonitrile containing 0.1% (v/v) formic acid and 0.05% (v/v) trifluoroacetic acid for Hcy extraction. This procedure was carried out in a 96-well plate format in an automated liquid handling platform to facilitate high-throughput analysis. The processed samples were separated on a Phenomenex CN column and quantitated by LC-MS/MS in multiple reaction monitoring (MRM) mode. The limit of detection was 0.12 μ mol/L (S/N=3) and the limit of quantification was 0.46 μ mol/L (S/N=10). The linear range was 1.16-148.00 μ mol/L (R2=0.994). The average recoveries were (103.0±4.97)%-(112.0±2.13)%. The intra-day relative standard deviations (RSDs) were 1.9%-4.6% and the inter-day RSDs were 1.5%-7.1%. DBS sample stability was confirmed by measuring same DBS samples stored for 0, 1, 2, 3, 4, 5, 6 and 14 days at -4, -20, 22 and 37℃, and an overall sample RSD<15% was found under each temperature. Processed sample stability within 48 hours was also confirmed with an overall sample RSD<5%. The comparison of this method with conventional biochemistry assay was made by measuring 47 blood samples both in an automated biochemistry analyzer (samples in plasma form) and with the LC-MS/MS method (samples in DBS form), which showed excellent correlation (R2=0.982).
A high-throughput method to measure homocysteine (Hcy) in dried blood spots (DBS) by liquid chromatography-tandem mass spectrometry (LC-MS/MS) was established. The DBS sample processing includes adding homocystine-D8 as internal standard, dithiothreitol (DTT) as reducing agent for bound Hcy forms, acetonitrile containing 0.1% (v/v) formic acid and 0.05% (v/v) trifluoroacetic acid for Hcy extraction. This procedure was carried out in a 96-well plate format in an automated liquid handling platform to facilitate high-throughput analysis. The processed samples were separated on a Phenomenex CN column and quantitated by LC-MS/MS in multiple reaction monitoring (MRM) mode. The limit of detection was 0.12 μ mol/L (S/N=3) and the limit of quantification was 0.46 μ mol/L (S/N=10). The linear range was 1.16-148.00 μ mol/L (R2=0.994). The average recoveries were (103.0±4.97)%-(112.0±2.13)%. The intra-day relative standard deviations (RSDs) were 1.9%-4.6% and the inter-day RSDs were 1.5%-7.1%. DBS sample stability was confirmed by measuring same DBS samples stored for 0, 1, 2, 3, 4, 5, 6 and 14 days at -4, -20, 22 and 37℃, and an overall sample RSD<15% was found under each temperature. Processed sample stability within 48 hours was also confirmed with an overall sample RSD<5%. The comparison of this method with conventional biochemistry assay was made by measuring 47 blood samples both in an automated biochemistry analyzer (samples in plasma form) and with the LC-MS/MS method (samples in DBS form), which showed excellent correlation (R2=0.982).
2016, 34(6): 572-576
doi: 10.3724/SP.J.1123.2016.02014
Abstract:
An online pressurized liquid microextraction-turbulent flow chromatography-high performance liquid chromatography (online PLME-TFC-HPLC) platform was configured for simultaneous determination of three phenylethanoid glycosides in Cistanche tubulosa. Micro amount powder of crude material (0.5 mg) was mixed with clean diatomaceous earth and packed into a vessel which then was put into a hollow guard column. To generate high temperature and high pressure, a long polyetheretherketone (PEEK) tube (1000 mm×0.13 mm) was linked to the end of the hollow guard column that was warmed in the column oven (70℃). The water containing 0.1% (v/v) formic acid acted as the extraction solvent and was delivered at 2.5 mL/min. Two electronic 6-port/2-channel valves were responsible for dividing the whole program into extraction and elution phases. The analytes were purified and enriched in a TurboFlow cyclone column, and back-flushed onto a Capcell PAK C18 AQ column under a gradient elution program with 0.1% (v/v) aqueous formic acid-acetonitrile at the elution phase. The ultraviolet wavelength was set at 340 nm to monitor phenylethanoid glycosides. The calibration curves for the three phenylethanoid glycosides revealed good linearities in the range of 1-200 mg/L (r>0.999). The limits of quantification (LOQs) were 0.50 mg/L (echinacoside), 0.25 mg/L (acteoside) and 0.38 mg/L (isoacteoside). The spiked recoveries were in the range of 83.13%-114.00% with the relative standard deviations (RSDs) between 1.89% and 13.34%. All the results indicated that this method is facile, efficient, reliable, and advantageous at time, labor, solvent, and material savings. The method also reduces the degradation risks and is suitable for the determination of phenylethanoid glycosides in Cistanche tubulosa.
An online pressurized liquid microextraction-turbulent flow chromatography-high performance liquid chromatography (online PLME-TFC-HPLC) platform was configured for simultaneous determination of three phenylethanoid glycosides in Cistanche tubulosa. Micro amount powder of crude material (0.5 mg) was mixed with clean diatomaceous earth and packed into a vessel which then was put into a hollow guard column. To generate high temperature and high pressure, a long polyetheretherketone (PEEK) tube (1000 mm×0.13 mm) was linked to the end of the hollow guard column that was warmed in the column oven (70℃). The water containing 0.1% (v/v) formic acid acted as the extraction solvent and was delivered at 2.5 mL/min. Two electronic 6-port/2-channel valves were responsible for dividing the whole program into extraction and elution phases. The analytes were purified and enriched in a TurboFlow cyclone column, and back-flushed onto a Capcell PAK C18 AQ column under a gradient elution program with 0.1% (v/v) aqueous formic acid-acetonitrile at the elution phase. The ultraviolet wavelength was set at 340 nm to monitor phenylethanoid glycosides. The calibration curves for the three phenylethanoid glycosides revealed good linearities in the range of 1-200 mg/L (r>0.999). The limits of quantification (LOQs) were 0.50 mg/L (echinacoside), 0.25 mg/L (acteoside) and 0.38 mg/L (isoacteoside). The spiked recoveries were in the range of 83.13%-114.00% with the relative standard deviations (RSDs) between 1.89% and 13.34%. All the results indicated that this method is facile, efficient, reliable, and advantageous at time, labor, solvent, and material savings. The method also reduces the degradation risks and is suitable for the determination of phenylethanoid glycosides in Cistanche tubulosa.
2016, 34(6): 577-582
doi: 10.3724/SP.J.1123.2016.01034
Abstract:
A method for the simultaneous determination of triclopyricarb and oxadiargyl residues in vegetative foods was developed using QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acidic acetonitrile, and then cleaned up by primary secondary amine (PSA) and NH2 adsorbents. The analytes were separated on a C18 column with isocratic gradient elution of 0.1%(v/v) formic acid in water (containing 2 mmol/L ammonium acetate)-methanol (2:8, v/v) at a flow rate of 0.25 mL/min. The mass spectrometry was carried out with electrospray positive ion source (ESI+) in multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions, and the quantitative analysis was carried out by matrix-matched external standard method. The results showed that calibration curves had good linearities for triclopyricarb and oxadiargyl, and the correlation coefficients (r2) were larger than 0.996; the limits of quantification (LOQs, S/N≥10) of triclopyricarb in the six matrices (grape, raisin, potato, rice, tomato, rapeseed) were 0.5 μg/kg, and the LOQs of oxadiargyl in the six different matrices were 1.0 μg/kg. When the articles were spiked with three levels of analytes (1×LOQ, 2×LOQ and 10×LOQ), the recoveries of triclopyricarb were from 71.6% to 112.1% with the RSDs from 2.6% to 12.1%; and the recoveries of oxadiargyl were from 77.6% to 118.8% with the RSDs from 3.6% to 14.3%. The method is highly effective, sensitive, accurate, and is suitable for the monitoring of triclopyricarb and oxadiargyl in vegetative foods.
A method for the simultaneous determination of triclopyricarb and oxadiargyl residues in vegetative foods was developed using QuEChERS-high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). The sample was extracted with acidic acetonitrile, and then cleaned up by primary secondary amine (PSA) and NH2 adsorbents. The analytes were separated on a C18 column with isocratic gradient elution of 0.1%(v/v) formic acid in water (containing 2 mmol/L ammonium acetate)-methanol (2:8, v/v) at a flow rate of 0.25 mL/min. The mass spectrometry was carried out with electrospray positive ion source (ESI+) in multiple reaction monitoring (MRM) mode. The qualitative analysis was based on the retention times and characteristic ion pairs consisting of one parent ion and two fragment ions, and the quantitative analysis was carried out by matrix-matched external standard method. The results showed that calibration curves had good linearities for triclopyricarb and oxadiargyl, and the correlation coefficients (r2) were larger than 0.996; the limits of quantification (LOQs, S/N≥10) of triclopyricarb in the six matrices (grape, raisin, potato, rice, tomato, rapeseed) were 0.5 μg/kg, and the LOQs of oxadiargyl in the six different matrices were 1.0 μg/kg. When the articles were spiked with three levels of analytes (1×LOQ, 2×LOQ and 10×LOQ), the recoveries of triclopyricarb were from 71.6% to 112.1% with the RSDs from 2.6% to 12.1%; and the recoveries of oxadiargyl were from 77.6% to 118.8% with the RSDs from 3.6% to 14.3%. The method is highly effective, sensitive, accurate, and is suitable for the monitoring of triclopyricarb and oxadiargyl in vegetative foods.
2016, 34(6): 583-590
doi: 10.3724/SP.J.1123.2016.02016
Abstract:
A liquid chromatography-quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) coupled with QuEChERS pretreatment analytical method was established for the identification and quantification of 24 antihyperglycemic, antihypertensive and antihyperlipidemic drugs illegally added in health foods. The extraction conditions, including the volume ratio of ACN and H2O, the amount of MgSO4 & NaCl used, and the amount of C18 used, were optimized by response surface methodology. The quantitative analysis was based on the accurate masses of the first level of parent molecular ions and isotopic patterns, and accurate masses of the second level of fragment ions and a priori known retention times. The established QuEChERS pretreatment method combined with LC-Q-TOF-MS was effective for the simultaneous characterization and quantification of antihyperglycemic, antihypertensive and antihyperlipidemic drugs with high selectivity, a high linearity (r2>0.997) in wide range, low LODs and LOQs, and high precision. The method was successfully applied to determinate the drugs illegally added in the fifteen health food samples, the five of which were positive samples.
A liquid chromatography-quadrupole-time of flight mass spectrometry (LC-Q-TOF-MS) coupled with QuEChERS pretreatment analytical method was established for the identification and quantification of 24 antihyperglycemic, antihypertensive and antihyperlipidemic drugs illegally added in health foods. The extraction conditions, including the volume ratio of ACN and H2O, the amount of MgSO4 & NaCl used, and the amount of C18 used, were optimized by response surface methodology. The quantitative analysis was based on the accurate masses of the first level of parent molecular ions and isotopic patterns, and accurate masses of the second level of fragment ions and a priori known retention times. The established QuEChERS pretreatment method combined with LC-Q-TOF-MS was effective for the simultaneous characterization and quantification of antihyperglycemic, antihypertensive and antihyperlipidemic drugs with high selectivity, a high linearity (r2>0.997) in wide range, low LODs and LOQs, and high precision. The method was successfully applied to determinate the drugs illegally added in the fifteen health food samples, the five of which were positive samples.
2016, 34(6): 591-595
doi: 10.3724/SP.J.1123.2016.03009
Abstract:
A method of the preparation of galangin and kaempferide from Alpinia officinarum Hance flavonoids using preparative high-performance liquid chromatography (Prep-HPLC) was established. After the Alpinia officinarum Hance flavonoids was purified by HPD-600 resin-based column chromatography, the flavonoid components were separated by Prep-HPLC on a Venusil XBP-C18 column (250 mm×21 mm, 5.0 μ m). The mixture of methanol and 0.6% (v/v) acetic acid solution (58:42, v/v) was used as mobile phase at a flow rate of 7.0 mL/min. The sample volume was 700 μ L and the UV detection wavelength was 360 nm. With MS and NMR, the structures of component I and component II of the Alpinia officinarum Hance flavonoids were identified. The average relative molecular mass of the component I was 269, the same as galangin; and that of the component II was 299, the same as kaempferide. HPLC analysis showed that the purities of galangin and kaempferide were 99.5% and 99.7% respectively. The method is simple and of low toxicity. It can be applied to the separation and preparation of galangin and kaempferide.
A method of the preparation of galangin and kaempferide from Alpinia officinarum Hance flavonoids using preparative high-performance liquid chromatography (Prep-HPLC) was established. After the Alpinia officinarum Hance flavonoids was purified by HPD-600 resin-based column chromatography, the flavonoid components were separated by Prep-HPLC on a Venusil XBP-C18 column (250 mm×21 mm, 5.0 μ m). The mixture of methanol and 0.6% (v/v) acetic acid solution (58:42, v/v) was used as mobile phase at a flow rate of 7.0 mL/min. The sample volume was 700 μ L and the UV detection wavelength was 360 nm. With MS and NMR, the structures of component I and component II of the Alpinia officinarum Hance flavonoids were identified. The average relative molecular mass of the component I was 269, the same as galangin; and that of the component II was 299, the same as kaempferide. HPLC analysis showed that the purities of galangin and kaempferide were 99.5% and 99.7% respectively. The method is simple and of low toxicity. It can be applied to the separation and preparation of galangin and kaempferide.
2016, 34(6): 596-601
doi: 10.3724/SP.J.1123.2016.03019
Abstract:
A rapid on-site method has been developed for the identification of eight prohibited antibiotics in cosmetics using extraction nano-electrospray coupled with ion mobility spectrometry. The experimental conditions for capillary pulling, extraction nano-electrospray, and ion mobility spectrometry were investigated and optimized. Under the optimum conditions, the limits of detection (LODs) for the eight prohibited antibiotics were 20 mg/kg. The instrumental analysis time for a single ion mobility spectrometry run was less than 20 ms, and the total period for sample analysis was less than 30 s. The suspicious positive samples were subjected to further verification by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The proposed method is rapid, efficient with greatly simplified work flows and can provide potential analytical possibility for outside-the-lab screening of cosmetics for the presence of illicit ingredients.
A rapid on-site method has been developed for the identification of eight prohibited antibiotics in cosmetics using extraction nano-electrospray coupled with ion mobility spectrometry. The experimental conditions for capillary pulling, extraction nano-electrospray, and ion mobility spectrometry were investigated and optimized. Under the optimum conditions, the limits of detection (LODs) for the eight prohibited antibiotics were 20 mg/kg. The instrumental analysis time for a single ion mobility spectrometry run was less than 20 ms, and the total period for sample analysis was less than 30 s. The suspicious positive samples were subjected to further verification by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The proposed method is rapid, efficient with greatly simplified work flows and can provide potential analytical possibility for outside-the-lab screening of cosmetics for the presence of illicit ingredients.
2016, 34(6): 602-607
doi: 10.3724/SP.J.1123.2016.01020
Abstract:
Adjuvant arthritis (AA) rats induced by Freund's complete adjuvant (FCA) were used to observe the changes of the degree of swelling in the toes and pathomorphology of ankle joint tissue. Gas chromatography-time-of-flight mass spectrometry (GC-TOF MS) was employed to detect the metabolite spectrum in rat urine with AA, and the data were analyzed by principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), and to explore its possible pathogenesis. Several metabolites based on the variable importance in the projection values (VIP>1), P value (<0.05) and screening in databases were identified. The results showed that 20 potential biomarkers such as isocitric acid, α-ketoglutaric acid, citraconic acid, creatine and 3-hydroxybutyric acid which had a significant contribution to classification were selected. Comparing with the normal group, AA rats present an abnormal metabolism. This study illustrates that AA metabolomics pathogenesis may be related to regulating the dysfunction of energy metabolism, amino acid metabolism and fatty acid metabolism.
Adjuvant arthritis (AA) rats induced by Freund's complete adjuvant (FCA) were used to observe the changes of the degree of swelling in the toes and pathomorphology of ankle joint tissue. Gas chromatography-time-of-flight mass spectrometry (GC-TOF MS) was employed to detect the metabolite spectrum in rat urine with AA, and the data were analyzed by principal component analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA), and to explore its possible pathogenesis. Several metabolites based on the variable importance in the projection values (VIP>1), P value (<0.05) and screening in databases were identified. The results showed that 20 potential biomarkers such as isocitric acid, α-ketoglutaric acid, citraconic acid, creatine and 3-hydroxybutyric acid which had a significant contribution to classification were selected. Comparing with the normal group, AA rats present an abnormal metabolism. This study illustrates that AA metabolomics pathogenesis may be related to regulating the dysfunction of energy metabolism, amino acid metabolism and fatty acid metabolism.
2016, 34(6): 608-614
doi: 10.3724/SP.J.1123.2016.03010
Abstract:
A method was developed for the analysis of 24 pesticide residues in tobacco based on gas chromatography-time of flight mass spectrometry (GC-TOF MS) under negative chemical ionization (NCI) and electron impact ionization (EI) modes coupled with microwave-assisted extraction. The tobacco samples were extracted with 10 mL dichloromethane-n-hexane (3:1, v/v) for 10 min at 100℃ by microwave-assisted extraction, and cleaned up by a florisil solid phase extraction cartridge, then detected by GC-TOF MS. For GC-NCI-TOF MS and GC-EI-TOF MS, the linear correlation coefficients (r2) were both better than 0.99, the relative standard deviations (RSD) were less than 8.6% and 9.1%, the limits of quantification ranged from 0.3 μg/kg to 6.9 μg/kg and 10.2 μg/kg to 44.9 μg/kg, and the recoveries ranged from 75.2% to 94.8% and 75.0% to 95.1% at three spiked levels, respectively. Comparison of the total ion chromatograms and mass spectra under NCI and EI modes, the NCI modes have the advantages of higher selectivity with better matrix interference resistance and simpler spectrogram. The detection limits in NCI mode were lower by more than one order of magnitude than those in EI mode, GC-NCI-TOF MS method was superior in analyzing low level of pesticide residues and complex matrix.
A method was developed for the analysis of 24 pesticide residues in tobacco based on gas chromatography-time of flight mass spectrometry (GC-TOF MS) under negative chemical ionization (NCI) and electron impact ionization (EI) modes coupled with microwave-assisted extraction. The tobacco samples were extracted with 10 mL dichloromethane-n-hexane (3:1, v/v) for 10 min at 100℃ by microwave-assisted extraction, and cleaned up by a florisil solid phase extraction cartridge, then detected by GC-TOF MS. For GC-NCI-TOF MS and GC-EI-TOF MS, the linear correlation coefficients (r2) were both better than 0.99, the relative standard deviations (RSD) were less than 8.6% and 9.1%, the limits of quantification ranged from 0.3 μg/kg to 6.9 μg/kg and 10.2 μg/kg to 44.9 μg/kg, and the recoveries ranged from 75.2% to 94.8% and 75.0% to 95.1% at three spiked levels, respectively. Comparison of the total ion chromatograms and mass spectra under NCI and EI modes, the NCI modes have the advantages of higher selectivity with better matrix interference resistance and simpler spectrogram. The detection limits in NCI mode were lower by more than one order of magnitude than those in EI mode, GC-NCI-TOF MS method was superior in analyzing low level of pesticide residues and complex matrix.
2016, 34(6): 615-620
doi: 10.3724/SP.J.1123.2016.03015
Abstract:
A method for the determination of ten migratory organotin compounds in toys was developed using headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Toy materials were soaked in 0.07 mol/L HCl for 2 h, then the pH of the soak solution was adjusted to 4.7 by HAc-NaAc buffer. After ethylized with sodium tetraethylborate (NaBEt4), the soaked solution was agitated and the headspace solid phase microextraction was performed with a 100 μ m polydimethylsiloxane (PDMS) fiber. After extraction, the SPME fiber was directly injected into the GC inlet, and the organotin compounds were separated on a DB-5 capillary column. The limits of detection for the ten organotin compounds were in the range of 0.5-5 μg/kg. The recoveries were in the ranges of 80.7%-118.7% and 86.2%-120.5% at the spiked levels of 0.500 μg/L and 5.00 μg/L. The relation standard deviations (RSDs) were all less than 15%. This method has been used to determine migratory organotin in accessible parts of toys, including coating, plastic, wood and textile. The method is simple, fast, sensitive and solvent-free.
A method for the determination of ten migratory organotin compounds in toys was developed using headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Toy materials were soaked in 0.07 mol/L HCl for 2 h, then the pH of the soak solution was adjusted to 4.7 by HAc-NaAc buffer. After ethylized with sodium tetraethylborate (NaBEt4), the soaked solution was agitated and the headspace solid phase microextraction was performed with a 100 μ m polydimethylsiloxane (PDMS) fiber. After extraction, the SPME fiber was directly injected into the GC inlet, and the organotin compounds were separated on a DB-5 capillary column. The limits of detection for the ten organotin compounds were in the range of 0.5-5 μg/kg. The recoveries were in the ranges of 80.7%-118.7% and 86.2%-120.5% at the spiked levels of 0.500 μg/L and 5.00 μg/L. The relation standard deviations (RSDs) were all less than 15%. This method has been used to determine migratory organotin in accessible parts of toys, including coating, plastic, wood and textile. The method is simple, fast, sensitive and solvent-free.
2016, 34(6): 621-624
doi: 10.3724/SP.J.1123.2016.01029
Abstract:
Virtual simulation technology has been widely proposed as a significant technological advance that can offer a novel form for education. Especially in the case of chemistry, virtual reality technology facilitates learning process surpassing major restrictions characterizing traditional educational methods. In this system, some popular softwares including 3Ds Max and Unity 3D are used to develop a fully immersive, interactive and three-dimensional simulation system of gas chromatography (GC). Three modules are included in this system. First module is the introduction of the instrument. Second module is a three-dimensional display of the structures, which are modeled by 3Ds Max and interacted by Unity 3D. The last module focuses on the simulation experiments, and this module is made by Unity 3D. All models created in this system are three-dimensional and the scenes are lifelike, so that all aspects of the instrument are presented to users clearly. Using this system to learn about the principles and structures of the instrument, users would feel that they were in a real laboratory and could master all related skills more easily. This system is not only a powerful tool to satisfy the need of instrument training and experimental teaching of chemistry, but also an excellent example of virtual simulation applied in chemistry.
Virtual simulation technology has been widely proposed as a significant technological advance that can offer a novel form for education. Especially in the case of chemistry, virtual reality technology facilitates learning process surpassing major restrictions characterizing traditional educational methods. In this system, some popular softwares including 3Ds Max and Unity 3D are used to develop a fully immersive, interactive and three-dimensional simulation system of gas chromatography (GC). Three modules are included in this system. First module is the introduction of the instrument. Second module is a three-dimensional display of the structures, which are modeled by 3Ds Max and interacted by Unity 3D. The last module focuses on the simulation experiments, and this module is made by Unity 3D. All models created in this system are three-dimensional and the scenes are lifelike, so that all aspects of the instrument are presented to users clearly. Using this system to learn about the principles and structures of the instrument, users would feel that they were in a real laboratory and could master all related skills more easily. This system is not only a powerful tool to satisfy the need of instrument training and experimental teaching of chemistry, but also an excellent example of virtual simulation applied in chemistry.
2016, 34(6): 625-634
doi: 10.3724/SP.J.1123.2016.03003
Abstract:
Detection of electrolytic conductivity can be accurately and simply performed. If such detection can be used for the study of ionic mobility, it may supply an accurate, simple and cheap method for the study. This work develops a novel theoretical method for such a study with electrolytic conductivity. An empirical equation for mono-valent ionic mobility is chosen as the studied target. By adequate data of conductivity of 19 mono-mono-valent electrolytes, we correct the empirical equation with near 10% maximum bias as an accurate one with 5% maximum bias with no more than 0.05 mol/L ionic strength. The predictions with the corrected equation are in good agreement with the exact mobilities of salt ions detected by moving boundary method and in high coincidence with the precise mobilities of the 32 large organic ions obtained by the Lucy's equation. Thus, the work also shows the high agreement among the conductivities and mobilities of the 19 small inorganic and the 32 large organic ions. A more accurate equation with 2% maximum deviation is given under the ionic strength of 0.02 mol/L. The advanced approach holds the special advantages. Firstly, adequate electrolytic conductivities in references can be used for the study of ionic mobility. Secondly, it makes the further study very easy due to the simple detection of the electrolyte conductivity.
Detection of electrolytic conductivity can be accurately and simply performed. If such detection can be used for the study of ionic mobility, it may supply an accurate, simple and cheap method for the study. This work develops a novel theoretical method for such a study with electrolytic conductivity. An empirical equation for mono-valent ionic mobility is chosen as the studied target. By adequate data of conductivity of 19 mono-mono-valent electrolytes, we correct the empirical equation with near 10% maximum bias as an accurate one with 5% maximum bias with no more than 0.05 mol/L ionic strength. The predictions with the corrected equation are in good agreement with the exact mobilities of salt ions detected by moving boundary method and in high coincidence with the precise mobilities of the 32 large organic ions obtained by the Lucy's equation. Thus, the work also shows the high agreement among the conductivities and mobilities of the 19 small inorganic and the 32 large organic ions. A more accurate equation with 2% maximum deviation is given under the ionic strength of 0.02 mol/L. The advanced approach holds the special advantages. Firstly, adequate electrolytic conductivities in references can be used for the study of ionic mobility. Secondly, it makes the further study very easy due to the simple detection of the electrolyte conductivity.
