Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry...Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.展开更多
The utilization of supercritical fluids (SCF) in the Fischer-Tropsch Synthesis (FTS) further complicates the hydrocarbon products identification and analysis process due to the dilution of hydrocarbon peaks by the pre...The utilization of supercritical fluids (SCF) in the Fischer-Tropsch Synthesis (FTS) further complicates the hydrocarbon products identification and analysis process due to the dilution of hydrocarbon peaks by the predominant solvent peak. Therefore, in this project, a custom-made Gas Chromatography (GC) analysis system was designed and implemented to identify and quantify SCF-FTS products. The FTS products were identified using two different methods. The first was through retention time matching by injecting standard solutions, and the second was through the use of the GC/MS system. The quantification of CO and CH4 was achieved by using external standards, where the CO conversion was calculated by relating the peak area of CO to the peak area of an internal standard (argon) while the CH4 selectivity was calculated by relating the peak area of CH4 to that of CO. After setting and calibrating the GC system, two reaction conditions (gas phase: 240°C, 20 bar syngas with 2:1 H2:CO molar feed ratio and for the supercritical fluids FTS (SCF-FTS): 240°C, 65 bar with 20 bar syngas partial pressure and 2:1 H2:CO molar feed ratio) were used to compare the different FTS reaction media. The comparison between the gas phase FTS and the SCF-FTS showed the following: carbon monoxide conversion was improved by 14% in the SCF-FTS, while the hydrocarbon product profile SCF-FTS showed 78% reduction in light hydrocarbons (C1 - C4) products, 35% increase in middle distillates (C11 - C22) products compared to gas phase FTS. These improvements have resulted in higher chain growth probability for the SCF-FTS (α = 0.85) compared to the gas phase FTS (α = 0.76). These results are generally in agreement with previously reported enhancement in the SCF-FTS[1].展开更多
A novel on-line system composed of supercritical fluid extraction(SFE), dilution line and reverse phase liquid chromatography/mass spectrometry(RPLC/MS) was constructed for on-line extraction and reverse phase separat...A novel on-line system composed of supercritical fluid extraction(SFE), dilution line and reverse phase liquid chromatography/mass spectrometry(RPLC/MS) was constructed for on-line extraction and reverse phase separation of some fat-soluble components in foods. Three columns including a trap column,concentration column and analytical column were used for trapping the fat-soluble components, on-line enrichment and reverse phase separation, respectively. Capsaicinoids were on-line extracted by a CO_2 supercritical fluid, then concentrated and separated by using the C_(18) columns, finally detected by mass spectrometry(MS). Capsaicin eluted at 10.1 min and limit of detection(LOD, S/N=3) for the standard solution is 0.55pg. The linearity was calculated with a value of coefficient of determination(R^2)≥0.998 in the range of 1.1–8.5 ng. Concentrations of capsaicin in the green, yellow, and red bell peppers were determined to be 60.33 ng/g, 31.79 ng/g, 35.38ng/g, respectively.展开更多
OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercriti...OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercritical fluid extraction(SFE) with CO 2,and the constituents of the volatile oil extracts were analyzed by gas chromatography-mass spectrometry(GC-MS).The relative content of each component was calculated using peak area normalization.RESULTS:The optimized SFE conditions were 45 MPa at 35℃ for 2 h.Twenty-four compounds were identified in the extract from the Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) mixture,and six of these had relative contents >1.These compounds were 1,2-dimethoxy-4-(2-propenyl)-benzene;1,2,3-trimethoxy-5-(2-propenyl)-benzene;β-asarone;(Z,Z) 9,12-octadecadienoic acid;(Z) 6-octadecenoic acid;and ethyl oleate.Combination of the herbs increased the number of pharmacologically active substances in the extract and decreased the number of compounds with one benzene ring compared with the extracts from the individual herbs.CONCLUSION:These results indicate there is a synergistic relationship among the compounds in these herbs.展开更多
Supercritical fluid chromatography(SFC),which uses supercritical fluid with higher diffusivity and lower viscosity than liquid as its mobile phase,can provide fast,green,high-throughput and good performance methods fo...Supercritical fluid chromatography(SFC),which uses supercritical fluid with higher diffusivity and lower viscosity than liquid as its mobile phase,can provide fast,green,high-throughput and good performance methods for the analysis of complicated samples.It is an advantageous alternative for the separation of polar and nonpolar compounds,and even chiral isomers.As an important constituent of living organisms,lipids and the related lipidomics researches have attracted dramatic attention during the past years.The separation and identification of lipids and lipid isomers are of great significance and remain challenging.In this mini-review,the principle of SFC and its applications in lipid isomer separation are summarized.展开更多
基金the financial support from China Postdoctoral Science Foundation(2018M643205)
文摘Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.
文摘The utilization of supercritical fluids (SCF) in the Fischer-Tropsch Synthesis (FTS) further complicates the hydrocarbon products identification and analysis process due to the dilution of hydrocarbon peaks by the predominant solvent peak. Therefore, in this project, a custom-made Gas Chromatography (GC) analysis system was designed and implemented to identify and quantify SCF-FTS products. The FTS products were identified using two different methods. The first was through retention time matching by injecting standard solutions, and the second was through the use of the GC/MS system. The quantification of CO and CH4 was achieved by using external standards, where the CO conversion was calculated by relating the peak area of CO to the peak area of an internal standard (argon) while the CH4 selectivity was calculated by relating the peak area of CH4 to that of CO. After setting and calibrating the GC system, two reaction conditions (gas phase: 240°C, 20 bar syngas with 2:1 H2:CO molar feed ratio and for the supercritical fluids FTS (SCF-FTS): 240°C, 65 bar with 20 bar syngas partial pressure and 2:1 H2:CO molar feed ratio) were used to compare the different FTS reaction media. The comparison between the gas phase FTS and the SCF-FTS showed the following: carbon monoxide conversion was improved by 14% in the SCF-FTS, while the hydrocarbon product profile SCF-FTS showed 78% reduction in light hydrocarbons (C1 - C4) products, 35% increase in middle distillates (C11 - C22) products compared to gas phase FTS. These improvements have resulted in higher chain growth probability for the SCF-FTS (α = 0.85) compared to the gas phase FTS (α = 0.76). These results are generally in agreement with previously reported enhancement in the SCF-FTS[1].
基金supported by the National Natural Science Foundation of China (No. 21621003)
文摘A novel on-line system composed of supercritical fluid extraction(SFE), dilution line and reverse phase liquid chromatography/mass spectrometry(RPLC/MS) was constructed for on-line extraction and reverse phase separation of some fat-soluble components in foods. Three columns including a trap column,concentration column and analytical column were used for trapping the fat-soluble components, on-line enrichment and reverse phase separation, respectively. Capsaicinoids were on-line extracted by a CO_2 supercritical fluid, then concentrated and separated by using the C_(18) columns, finally detected by mass spectrometry(MS). Capsaicin eluted at 10.1 min and limit of detection(LOD, S/N=3) for the standard solution is 0.55pg. The linearity was calculated with a value of coefficient of determination(R^2)≥0.998 in the range of 1.1–8.5 ng. Concentrations of capsaicin in the green, yellow, and red bell peppers were determined to be 60.33 ng/g, 31.79 ng/g, 35.38ng/g, respectively.
基金Supported by Shanxi Science and Technology Tackling Fund(No.20100311090)Shanxi Provincial Health Department Science and Technology Tackling Fund (No.2008034)
文摘OBJECTIVE:To analyze the constituents of volatile oils extracted from Yuan Zhi(Radix Polygalae),Shi Chang Pu(Acorus Tatarinowii),and a mixture of the two herbs.METHODS:The volatile oils were extracted using supercritical fluid extraction(SFE) with CO 2,and the constituents of the volatile oil extracts were analyzed by gas chromatography-mass spectrometry(GC-MS).The relative content of each component was calculated using peak area normalization.RESULTS:The optimized SFE conditions were 45 MPa at 35℃ for 2 h.Twenty-four compounds were identified in the extract from the Yuan Zhi(Radix Polygalae) and Shi Chang Pu(Acorus Tatarinowii) mixture,and six of these had relative contents >1.These compounds were 1,2-dimethoxy-4-(2-propenyl)-benzene;1,2,3-trimethoxy-5-(2-propenyl)-benzene;β-asarone;(Z,Z) 9,12-octadecadienoic acid;(Z) 6-octadecenoic acid;and ethyl oleate.Combination of the herbs increased the number of pharmacologically active substances in the extract and decreased the number of compounds with one benzene ring compared with the extracts from the individual herbs.CONCLUSION:These results indicate there is a synergistic relationship among the compounds in these herbs.
基金the National Natural Science Foundation of China(Nos.21527809 and 21175005).
文摘Supercritical fluid chromatography(SFC),which uses supercritical fluid with higher diffusivity and lower viscosity than liquid as its mobile phase,can provide fast,green,high-throughput and good performance methods for the analysis of complicated samples.It is an advantageous alternative for the separation of polar and nonpolar compounds,and even chiral isomers.As an important constituent of living organisms,lipids and the related lipidomics researches have attracted dramatic attention during the past years.The separation and identification of lipids and lipid isomers are of great significance and remain challenging.In this mini-review,the principle of SFC and its applications in lipid isomer separation are summarized.
