Based on the fact that the first set of the linear relationship between z and lg/ ofstoichiometric displacement model for retention in reversed-phase liquid chromatography is separatelyproportional to contact surface ...Based on the fact that the first set of the linear relationship between z and lg/ ofstoichiometric displacement model for retention in reversed-phase liquid chromatography is separatelyproportional to contact surface area,a linear relationship between z and lg/ for both of polar and apolarsmall solute molecules was theoretically derived and experimentally tested.The j obtained,one of the secondset of the linear parameters,is a characterization parameter for organic solvent strength and the column phaseratio(?)is defined as the value of k’ when the partition coefficient of solute in two phases is unity.展开更多
A linear solvation energy relationships（LSERs） model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C18 column by means of reversed-phase high performan...A linear solvation energy relationships（LSERs） model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C18 column by means of reversed-phase high performance liquid cbromatography（RP-HPLC）. Three ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate （[Hmin][BF4]）, 1-butyl-3-methylimidazolium tetrafluoroborate（[Bmin][BF4]） and 1-octyl-3-methylimidazolium tetrafluoroborate（[OMIm][BF4]） as additives, were added to a methanol-water mobile phase. The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated, and a comparison between the predicted and experimental retention factors was made via the LSERs model, which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.展开更多
The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid-phase micro- extraction （HS-SPME） and headspace liquid-phase microextraction （HS-LPME） combined with gas chromatography-ma...The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid-phase micro- extraction （HS-SPME） and headspace liquid-phase microextraction （HS-LPME） combined with gas chromatography-mass spectrometry （GC-MS）. The main volatiles from Mosla chinensis Maxim were studied in this paper. It can be seen that 61 compounds were separated and identified. Forty-nine volatile compounds were identified by SPME method, mainly including myrcene, a-terpinene, p-cymene, （E）-ocimene, thymol, thymol acetate and （E）-fl-farnesene. Forty-five major volatile compounds were identified by LPME method, including a-thujene, a-pinene, camphene, butanoic acid, 2-methylpropyl ester, myrcene, butanoic acid, butyl ester, a-terpinene, p-cymene, （E）-ocimene, butane, 1,1-dibutoxy-, thymol, thymol acetate and （E）-fl-farnesene. After analyzing the volatile compounds, multiple linear regression （MLR） method was used for building the regression model. Then the quantitative structure-retention relationship （QSRR） model was validated by predictive-ability test. The prediction results were in good agreement with the experimental values. The results demonstrated that headspace SPME-GC-MS and LPME-GC-MS are the simple, rapid and easy sample enrichment technique suitable for analysis of volatile compounds. This investigation provided an effective method for predicting the retention indices of new compounds even in the absence of the standard candidates.展开更多
An on-line UV spectrometric method for the quantitative determination ofmethanol increment of methanol-water in the mobile phase (i.e., of greater concentration than thatof the mobile phase) by frontal analysis (FA) o...An on-line UV spectrometric method for the quantitative determination ofmethanol increment of methanol-water in the mobile phase (i.e., of greater concentration than thatof the mobile phase) by frontal analysis (FA) of insulin in reversed phase liquid chromatography(RPLC) was presented. When the methanol increment concentration ranged from 0.05% to 0.50%,V(CH_3OH)/V(H_2O), a set of elution curves could be obtained at 198 nm by a diode-array detector inthe presence of 47% methanol, V(CH_3OH)/V(H_2O) containing 0.03% hydrochloric acid,V(CH_3OH-H_2O)/V(HCl) in the mobile phase. The plateau height of the elution curves of the methanolincrement was found to be proportional to the methanol increment in the mobile phase. The methanolincrement could be determined on a quantitative basis. When the method was used to investigate theelution curve of insulin by FA in RPLC, a small plateau, being the methanol increment, was detectedbefore the usual insulin plateau of each elution curve. In this case the methanol increment wasfound to vary with insulin concentration in the mobile phase. When that concentration was between0.025 mg/mL and 0.30 mg/mL, the methanol increment could be determined in the range from 0.03% to0.19% with a deviation of ±10%. A nuclear magnetic resonance spectrometer (NMR) was also employedto confirm the obtained result. A methodology with a very rigorous experimental procedure forobtaining results of such accuracy is also included. The presented result may be used to prove thata displacement process definitely occurs as insulin is adsorbed by the RPLC stationary phase inFA.展开更多
以十通阀和捕集柱接口形式,构建了弱阴离子交换/反相(WAX/RP)二维液相色谱分离系统。通过将第一维离子交换色谱分析中的前部集中洗脱出的弱保留组分收集后单独分析,剩余样品进一步采用二维液相色谱分析,可以有效避免第二维色谱柱对特殊...以十通阀和捕集柱接口形式,构建了弱阴离子交换/反相(WAX/RP)二维液相色谱分离系统。通过将第一维离子交换色谱分析中的前部集中洗脱出的弱保留组分收集后单独分析,剩余样品进一步采用二维液相色谱分析,可以有效避免第二维色谱柱对特殊样品局部集中流出导致的第二维分离超柱容量问题,提高了系统的整体分离能力。使用4种蛋白胰蛋白酶酶解后的多肽样品评价该系统,在不分流的系统中共检测到115个峰。对第一维分离的前15 m in分流后得到的组分单独分析,共识别出58个峰,后续的二维分离中共得到78个峰。2种方法相比,第二种方法检测峰数增加了21个,一些低丰度的组分在弱保留组分收集后被识别。展开更多
基金the National Natural Science Foundation of China
文摘Based on the fact that the first set of the linear relationship between z and lg/ ofstoichiometric displacement model for retention in reversed-phase liquid chromatography is separatelyproportional to contact surface area,a linear relationship between z and lg/ for both of polar and apolarsmall solute molecules was theoretically derived and experimentally tested.The j obtained,one of the secondset of the linear parameters,is a characterization parameter for organic solvent strength and the column phaseratio(?)is defined as the value of k’ when the partition coefficient of solute in two phases is unity.
基金Supported by the Basic Science Research Program Through the National Research Foundation(NRF) of Korea Funded by the Ministry of Education,Science and Technology(No.2010-0015731)
文摘A linear solvation energy relationships（LSERs） model was used to examine the fundamental chemical interactions governing the retention of 9 organic compounds on a C18 column by means of reversed-phase high performance liquid cbromatography（RP-HPLC）. Three ionic liquids, 1-hexyl-3-methylimidazolium tetrafluoroborate （[Hmin][BF4]）, 1-butyl-3-methylimidazolium tetrafluoroborate（[Bmin][BF4]） and 1-octyl-3-methylimidazolium tetrafluoroborate（[OMIm][BF4]） as additives, were added to a methanol-water mobile phase. The effects of these three ionic liquids additives on the retention of nine organic compounds were investigated, and a comparison between the predicted and experimental retention factors was made via the LSERs model, which indicated that the LSERs model could be used to reproduce the experimental retention factors of the solutes under different mobile phase conditions. It is also a useful tool for modeling the interactions of the solutes between the stationary and mobile phases and evaluating the retention characteristics of HPLC.
基金Project supported by the Natural Science Foundation Programof Zhejiang Province （No. Y407308）, the Ministry of Science and Technology of Zhejiang Province （No. 201 OR 10044） and the Sprout Talented Project Program of Zhejiang Province （No. 2008R40G2020019）.
文摘The volatile compounds emitted from Mosla chinensis Maxim were analyzed by headspace solid-phase micro- extraction （HS-SPME） and headspace liquid-phase microextraction （HS-LPME） combined with gas chromatography-mass spectrometry （GC-MS）. The main volatiles from Mosla chinensis Maxim were studied in this paper. It can be seen that 61 compounds were separated and identified. Forty-nine volatile compounds were identified by SPME method, mainly including myrcene, a-terpinene, p-cymene, （E）-ocimene, thymol, thymol acetate and （E）-fl-farnesene. Forty-five major volatile compounds were identified by LPME method, including a-thujene, a-pinene, camphene, butanoic acid, 2-methylpropyl ester, myrcene, butanoic acid, butyl ester, a-terpinene, p-cymene, （E）-ocimene, butane, 1,1-dibutoxy-, thymol, thymol acetate and （E）-fl-farnesene. After analyzing the volatile compounds, multiple linear regression （MLR） method was used for building the regression model. Then the quantitative structure-retention relationship （QSRR） model was validated by predictive-ability test. The prediction results were in good agreement with the experimental values. The results demonstrated that headspace SPME-GC-MS and LPME-GC-MS are the simple, rapid and easy sample enrichment technique suitable for analysis of volatile compounds. This investigation provided an effective method for predicting the retention indices of new compounds even in the absence of the standard candidates.
文摘An on-line UV spectrometric method for the quantitative determination ofmethanol increment of methanol-water in the mobile phase (i.e., of greater concentration than thatof the mobile phase) by frontal analysis (FA) of insulin in reversed phase liquid chromatography(RPLC) was presented. When the methanol increment concentration ranged from 0.05% to 0.50%,V(CH_3OH)/V(H_2O), a set of elution curves could be obtained at 198 nm by a diode-array detector inthe presence of 47% methanol, V(CH_3OH)/V(H_2O) containing 0.03% hydrochloric acid,V(CH_3OH-H_2O)/V(HCl) in the mobile phase. The plateau height of the elution curves of the methanolincrement was found to be proportional to the methanol increment in the mobile phase. The methanolincrement could be determined on a quantitative basis. When the method was used to investigate theelution curve of insulin by FA in RPLC, a small plateau, being the methanol increment, was detectedbefore the usual insulin plateau of each elution curve. In this case the methanol increment wasfound to vary with insulin concentration in the mobile phase. When that concentration was between0.025 mg/mL and 0.30 mg/mL, the methanol increment could be determined in the range from 0.03% to0.19% with a deviation of ±10%. A nuclear magnetic resonance spectrometer (NMR) was also employedto confirm the obtained result. A methodology with a very rigorous experimental procedure forobtaining results of such accuracy is also included. The presented result may be used to prove thata displacement process definitely occurs as insulin is adsorbed by the RPLC stationary phase inFA.
文摘以十通阀和捕集柱接口形式,构建了弱阴离子交换/反相(WAX/RP)二维液相色谱分离系统。通过将第一维离子交换色谱分析中的前部集中洗脱出的弱保留组分收集后单独分析,剩余样品进一步采用二维液相色谱分析,可以有效避免第二维色谱柱对特殊样品局部集中流出导致的第二维分离超柱容量问题,提高了系统的整体分离能力。使用4种蛋白胰蛋白酶酶解后的多肽样品评价该系统,在不分流的系统中共检测到115个峰。对第一维分离的前15 m in分流后得到的组分单独分析,共识别出58个峰,后续的二维分离中共得到78个峰。2种方法相比,第二种方法检测峰数增加了21个,一些低丰度的组分在弱保留组分收集后被识别。
