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Yu YL, Shi MZ, Zhu SC, Cao J. Rapid stacking of amino acids in soybean and Dendrobium officinale by on-capillary sandwich derivatization in capillary electrophoresis. Food Res Int 2022; 162:112071. [DOI: 10.1016/j.foodres.2022.112071] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/04/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022]
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2
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Yan TC, Zhang HH, Cao J, Ye LH. Analysis of iodinated amino acids by microemulsion electrokinetic chromatography using aliphatic amine as a cosurfactant. J Chromatogr A 2022; 1685:463644. [DOI: 10.1016/j.chroma.2022.463644] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/21/2022] [Accepted: 11/07/2022] [Indexed: 11/11/2022]
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3
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Nanoemulsion supported microemulsion electrokinetic chromatography coupled with selected preconcentration techniques as an approach for analysis of highly hydrophobic compounds. J Chromatogr A 2022; 1677:463339. [PMID: 35870278 DOI: 10.1016/j.chroma.2022.463339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 07/11/2022] [Accepted: 07/11/2022] [Indexed: 11/20/2022]
Abstract
In this paper, an oil-in-water (O/W) nanoemulsion (NE) prepared by water cold dilution of an O/W microemulsion (ME) was introduced as a sample matrix in microemulsion electrokinetic capillary chromatography (MEEKC) for the highly hydrophobic compounds analysis. Several model compounds with log PO/W values in the 4.1-10.9 range, from different chemical groups, including retinol, α-tocopherol, cholecalciferol, phylloquinone, menaquinone-7, dichlorodiphenyltrichloroethane, ivermectin have been tested. As a proof of the concept of NE formation, a dynamic light scattering technique was employed to determine the size distribution profile of NE particles. Moreover, due to relatively low conductivity of the NE matrix (50-100 times lower in comparison to the separation buffer) and a negative electric charge provided to hydrophobic compounds through NE dispersed phase, NE matrices have been combined with preconcentration techniques based on electrokinetic dosing, namely field amplified sample injection (FASI) and pressure assisted electrokinetic injection (PAEKI). The detection limits for vitamin K1 and K2-MK7 in the NE matrix in combination with FASI (NE-MEEKC-FASI) as well as PAEKI (NE-MEEKC-PAEKI) were up to 42.9 and 12.1 ng mL-1, respectively. In comparison to standard hydrodynamic injection for microemulsion sample matrix NE-MEEKC-PAEKI grant 45-fold improvement in signal sensitivity. The study presents an innovative approach, as it enables the use of preconcentration techniques for highly hydrophobic compounds (log PO/W > 4), which was not previously possible for implementation in the electromigration techniques. Likewise, the use of organic solvents has been reduced by using ME as a solvent for stock solutions and diluting with water prior to the analysis. The application to real samples was investigated using a dietary supplement containing vitamin K2-MK7 obtained from the fermentation product of soybeans.
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Yu YL, Zhu SC, Shi MZ, Liu FM, Cao J. Two-step micelle-to-solvent stacking of arsenic species from foods in permanently coated tubing for capillary electrophoresis. J Chromatogr A 2022; 1673:463112. [DOI: 10.1016/j.chroma.2022.463112] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 04/19/2022] [Accepted: 05/01/2022] [Indexed: 10/18/2022]
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5
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Screening of lipase inhibitors in citrus fruits by electrophoretically - mediated microanalysis combined with molecular docking. J Food Compost Anal 2022. [DOI: 10.1016/j.jfca.2021.104185] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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6
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Shi L, Wang J, Feng J, Zhao S, Wang Z, Tao H, Liu S. Determination of chlorophenols in water using dispersive liquid-liquid microextraction coupled with water-in-oil microemulsion electrokinetic chromatography in normal stacking mode. J Sep Sci 2017; 40:2662-2670. [DOI: 10.1002/jssc.201700175] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2017] [Revised: 04/11/2017] [Accepted: 04/15/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Ludi Shi
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Jin Wang
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Jing Feng
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Sihan Zhao
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Zhengmeng Wang
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Hu Tao
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
| | - Shuhui Liu
- Shaanxi Key Laboratory of Natural Products and Chemical Biology, College of Chemistry and Pharmacy; Northwest A and F University; Yangling Shaanxi China
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Ye LH, Liu XD, Cao J, Chang YX, An M, Wang SL, Xu JJ, Peng LQ. Analysis of isoquinoline alkaloids using chitosan-assisted liquid-solid extraction followed by microemulsion liquid chromatography employing a sub-2-micron particle stationary phase. Electrophoresis 2016; 37:3118-3125. [PMID: 27699822 DOI: 10.1002/elps.201600114] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2016] [Revised: 08/05/2016] [Accepted: 08/30/2016] [Indexed: 11/09/2022]
Abstract
A simple, efficient, and green chitosan-assisted liquid-solid extraction method was developed for the sample preparation of isoquinoline derivative alkaloids followed by microemulsion LC. The optimized mobile phase consisted of 0.8% w/v of ethyl acetate, 1.0% w/v of SDS, 8.0% w/v of n-butanol, 0.1% v/v acetic acid, and 10% v/v ACN. Compared to pharmacopoeia method and organic solvent extraction, this new approach avoided the use of volatile organic solvents, replacing them with relatively small amounts of chitosan. Under the optimum conditions, good linearity (r2 > 0.9980) for all calibration curves and low detection limits between 0.05 and 0.10 μg/mL were achieved. The presented procedure was successfully applied to determine alkaloids in Rhizoma coptidis with satisfactory recoveries (81.3-106.4%).
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Affiliation(s)
- Li-Hong Ye
- Department of Traditional Chinese Medicine, Hangzhou Red Cross Hospital, Hangzhou, P. R., China
| | - Xi-De Liu
- Department of Traditional Chinese Medicine, Hangzhou Red Cross Hospital, Hangzhou, P. R., China
| | - Jun Cao
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, P. R., China
| | - Yan-Xu Chang
- Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine, Tianjin, P. R., China
| | - Mingrui An
- Department of Surgery, University of Michigan Medical Center, Ann Arbor, MI, USA
| | - Shu-Ling Wang
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, P. R., China
| | - Jing-Jing Xu
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, P. R., China
| | - Li-Qing Peng
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University, Hangzhou, P. R., China
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8
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Multivariable optimization of the micellar system for the ionic liquid-modified MEKC separation of phenolic acids. J Pharm Biomed Anal 2016; 126:1-8. [DOI: 10.1016/j.jpba.2016.04.027] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2015] [Revised: 03/28/2016] [Accepted: 04/17/2016] [Indexed: 11/21/2022]
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9
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Cao J, Wei J, Xiang C, Zhang M, Li B, Wan J, Su H, Li P. Separation and Determination of Four Tanshinones in Danshen and Related Medicinal Plants by Micellar Electrokinetic Chromatography Using Ionic Liquids as Modifier. J Chromatogr Sci 2016; 54:1435-44. [DOI: 10.1093/chromsci/bmw059] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2015] [Indexed: 12/23/2022]
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Abstract
Microemulsion electrokinetic chromatography (MEEKC) is a special mode of capillary electrophoresis employing a microemulsion as carrier electrolyte. Analytes may partition between the aqueous phase of the microemulsion and its oil droplets which act as a pseudostationary phase. The technique is well suited for the separation of neutral species, in which case charged oil droplets (obtained by addition of an anionic or cationic surfactant) are present. A single set of separation parameters may be sufficient for separation of a wide range of analytes belonging to quite different chemical classes. Fine-tuning of resolution and analysis time may be achieved by addition of organic solvents, by changes in the nature of the surfactants (and cosurfactants) used to stabilize the microemulsion, or by various additives that may undergo some additional interactions with the analytes. Besides the separation of neutral analytes (which may be the most important application area of MEEKC), it can also be employed for cationic and/or anionic species. In this chapter, MEEKC conditions are summarized that have proven their reliability for routine analysis. Furthermore, the mechanisms encountered in MEEKC allow an efficient on-capillary preconcentration of analytes, so that the problem of poor concentration sensitivity of ultraviolet absorbance detection is circumvented.
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Affiliation(s)
- Wolfgang Buchberger
- Institut für Analytische Chemie, Universität Linz, TNF-Tower, T 209, Altenbergerstraße 69, Linz, 4040, Austria.
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Derbina AA, Pirogov AV, Kargin ID, Shpigun OA. Application of water-in-oil microemulsions in microemulsion electrokinetic chromatography and as extractants of polar substances. JOURNAL OF ANALYTICAL CHEMISTRY 2015. [DOI: 10.1134/s1061934815100068] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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12
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Optimization of Micellar Electrokinetic Chromatography Method for the Simultaneous Determination of Seven Hydrophilic and Four Lipophilic Bioactive Components in Three Salvia Species. Molecules 2015; 20:15304-18. [PMID: 26307960 PMCID: PMC6331832 DOI: 10.3390/molecules200815304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 08/15/2015] [Accepted: 08/18/2015] [Indexed: 12/22/2022] Open
Abstract
A micellar electrokinetic chromatography (MEKC) method was developed for the simultaneous determination of seven hydrophilic phenolic acids and four lipophilic tanshinones in three Salvia species. In normal MEKC mode using SDS as surfactant, the investigated 11 compounds could not be well separated. Therefore, several buffer modifiers including β-cyclodextrins (β-CD), ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim]BF4) and organic solvents have been added to the buffer solution to improve the separation selectivity. Under the optimized conditions (BGE, 15 mM sodium tetraborate with 10 mM SDS, 5 mM β-CD, 10 mM [bmim]BF4 and 15% ACN (v/v) as additives; buffer pH, 9.8; voltage, 20 kV; temperature, 25 °C), the 11 investigated analytes could achieve baseline separation in 34 min. The proposed MEKC was additionally validated by evaluating the linearity (R(2) ≥ 0.9965), LODs (0.27-1.39 μg·mL(-1)), and recovery (94.26%-105.17%), demonstrating this method was reproducible, accurate and reliable. Moreover, the contents of the 11 compounds in three Salvia species, including S. miltiorrhiza, S. przewalskii and S. castanea were analyzed. The result showed that the established MEKC method was simple and practical for the simultaneous determination of the hydrophilic and lipophilic bioactive components in Salvia species, which could be used to effectively evaluate the quality of these valued medicinal plants.
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Cao J, Wei J, Tian K, Su H, Wan J, Li P. Simultaneous determination of seven phenolic acids in three Salvia species by capillary zone electrophoresis with β-cyclodextrin as modifier. J Sep Sci 2014; 37:3738-44. [PMID: 25296843 DOI: 10.1002/jssc.201400845] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 09/25/2014] [Accepted: 09/29/2014] [Indexed: 12/31/2022]
Abstract
A capillary zone electrophoresis method was developed for the simultaneous determination of seven phenolic acids, including protocatechuic aldehyde (1), salvianolic acid C (2), rosmarinic acid (3), salvianolic acid A (4), danshensu (5), salvianolic acid B (6), and protocatechuic acid (7), in Danshen and related medicinal plants. A running buffer composed of 20 mM sodium tetraborate adjusted to pH 9.0, and containing 12 mM β-cyclodextrin as modifier. Baseline separation was achieved within 17 min running at the voltage of 20 kV, temperature of 25°C and detection wavelength of 280 nm. The relative standard deviations of migration time ranged from 0.2 to 0.7% and the peak area ranged from 1.5 to 3.7% for the seven analytes, indicating the good repeatability of the proposed method. The method was extensively validated by evaluating the linearity (R(2) ≥ 0.9992), limits of detection (0.14-0.36 μg/mL), limits of quantification (0.47-1.19 μg/mL), and recovery (96.0-102.6%). Under the optimum conditions, samples of Danshen and related medicinal plants were analyzed using the developed method with high separation efficiency.
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Affiliation(s)
- Jiliang Cao
- State Key Laboratory of Quality Research in Chinese Medicine, Institute of Chinese Medical Sciences, University of Macau, Macau, China
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Cao W, Hu SS, Ye LH, Cao J. Dispersive micro-solid-phase extraction using mesoporous hybrid materials for simultaneous determination of semivolatile compounds from plant tea by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2014; 62:9683-9689. [PMID: 25231266 DOI: 10.1021/jf5029625] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
This report described the use of mesoporous hybrid materials (MHM) in a dispersive micro-solid-phase extraction procedure to extract semivolatile compounds from plant tea that were then analyzed by ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry. Dihydrotanshinone I, tanshinone I, cryptotanshinone, and tanshinone IIA were selected as the model compounds, and the extraction parameters, including mesoporous concentration, extraction time, sample agitation and desorption solvents, were optimized. The interaction with the analytes and the large surface area of the MHM facilitated the adsorption of analytes. The method showed good linearity, with correlation coefficients >0.9980 in the range 0.25-100 ng/mL, and low limits of detection (0.012-0.046 pg). Finally, the recovery values were 91-103% for Danshen tea, 89-102% for Danshen, and 88-96% for tanshinone capsules. The results showed that the proposed method was suitable for the extraction and determination of tanshinones in complex samples.
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Affiliation(s)
- Wan Cao
- College of Material Chemistry and Chemical Engineering, Hangzhou Normal University , 16, Xuelin Street, Xiasha High Education Zone, Hangzhou 310036, China
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15
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Hu SS, Cao W, Da JH, Dai HB, Cao J, Ye LH, Li XY, Chu C. Dispersive Micro Solid-Phase Extraction with Graphene Oxide for the Determination of Phenolic Compounds in Dietary Supplements by Ultra High Performance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Tandem Mass Spectrometry. FOOD ANAL METHOD 2014. [DOI: 10.1007/s12161-014-9959-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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16
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Ni X, Yu M, Cao Y, Cao G. Microstructure of microemulsion modified with ionic liquids in microemulsion electrokinetic chromatography and analysis of seven corticosteroids. Electrophoresis 2013; 34:2568-76. [DOI: 10.1002/elps.201300168] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 05/17/2013] [Accepted: 05/29/2013] [Indexed: 02/06/2023]
Affiliation(s)
- Xinjiong Ni
- School of Chemical and Material Engineering; Jiangnan University; Wuxi P. R. China
| | - Meijuan Yu
- School of Chemical and Material Engineering; Jiangnan University; Wuxi P. R. China
| | - Yuhua Cao
- School of Chemical and Material Engineering; Jiangnan University; Wuxi P. R. China
- The Key Laboratory of Food Colloids and Biotechnology; Ministry of Education; Wuxi P. R. China
| | - Guangqun Cao
- School of Chemical and Material Engineering; Jiangnan University; Wuxi P. R. China
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17
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Yang H, Ding Y, Cao J, Li P. Twenty-one years of microemulsion electrokinetic chromatography (1991-2012): A powerful analytical tool. Electrophoresis 2013; 34:1273-94. [DOI: 10.1002/elps.201200494] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 12/18/2012] [Accepted: 01/22/2013] [Indexed: 12/18/2022]
Affiliation(s)
- Hua Yang
- State Key Laboratory of Natural Medicines (China Pharmaceutical University); Nanjing; P. R. China
| | - Yao Ding
- State Key Laboratory of Natural Medicines (China Pharmaceutical University); Nanjing; P. R. China
| | - Jun Cao
- College of Material Chemistry and Chemical Engineering; Hangzhou Normal University; Hangzhou; P. R. China
| | - Ping Li
- State Key Laboratory of Natural Medicines (China Pharmaceutical University); Nanjing; P. R. China
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Yu L, Chu K, Ye H, Liu X, Yu L, Xu X, Chen G. Recent advances in microemulsion electrokinetic chromatography. Trends Analyt Chem 2012. [DOI: 10.1016/j.trac.2011.11.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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19
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Chen XJ, Zhao J, Wang YT, Huang LQ, Li SP. CE and CEC analysis of phytochemicals in herbal medicines. Electrophoresis 2011; 33:168-79. [DOI: 10.1002/elps.201100347] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Revised: 09/25/2011] [Accepted: 09/27/2011] [Indexed: 12/11/2022]
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20
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Huang HY, Liu WL, Singco B, Hsieh SH, Shih YH. On-line concentration sample stacking coupled with water-in-oil microemulsion electrokinetic chromatography. J Chromatogr A 2011; 1218:7663-9. [DOI: 10.1016/j.chroma.2011.05.091] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2011] [Revised: 04/28/2011] [Accepted: 05/26/2011] [Indexed: 02/06/2023]
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21
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Gotti R. Capillary electrophoresis of phytochemical substances in herbal drugs and medicinal plants. J Pharm Biomed Anal 2011; 55:775-801. [DOI: 10.1016/j.jpba.2010.11.041] [Citation(s) in RCA: 68] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2010] [Revised: 11/22/2010] [Accepted: 11/26/2010] [Indexed: 11/29/2022]
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22
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Cao Y, Ni X, Sheng J. Comparison of microstructures of microemulsion and swollen micelle in electrokinetic chromatography. J Chromatogr A 2011; 1218:2598-603. [DOI: 10.1016/j.chroma.2011.02.015] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 02/08/2011] [Accepted: 02/08/2011] [Indexed: 11/15/2022]
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Cao J, Dun W, Qu H. Evaluation of the addition of various surfactant-suspended carbon nanotubes in MEEKC with an in situ-synthesized surfactant system. Electrophoresis 2011; 32:408-13. [DOI: 10.1002/elps.201000535] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2010] [Revised: 11/30/2010] [Accepted: 12/03/2010] [Indexed: 11/09/2022]
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Ryan R, McEvoy E, Sheila Donegan, Power J, Altria K. Recent developments in the methodology and application of MEEKC. Electrophoresis 2010; 32:184-201. [DOI: 10.1002/elps.201000372] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 08/28/2010] [Accepted: 09/21/2010] [Indexed: 02/05/2023]
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25
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Xie F, Yu A, Cheng Y, Qi R, Li Q, Liu H, Zhang S. Rapid Separation and Determination of Five Phenolic Acids in Tobacco by CE. Chromatographia 2010. [DOI: 10.1365/s10337-010-1781-9] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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26
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Cao J, Qu H, Cheng Y. The use of novel ionic liquid-in-water microemulsion without the addition of organic solvents in a capillary electrophoretic system. Electrophoresis 2010; 31:3492-8. [DOI: 10.1002/elps.201000168] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Ryan R, Donegan S, Power J, Altria K. Advances in the theory and application of MEEKC. Electrophoresis 2010; 31:755-67. [DOI: 10.1002/elps.200900568] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Cao J, Li B, Chang YX, Li P. Direct on-line analysis of neutral analytes by dual sweeping via complexation and organic solvent field enhancement in nonionic MEKC. Electrophoresis 2009; 30:1372-9. [PMID: 19382135 DOI: 10.1002/elps.200800523] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Conventionally, neutral compounds cannot be separated by nonionic micelle capillary electrophoresis. In this report, the development of a novel on-line preconcentration technique combining dual sweeping based on complexation and organic solvent field enhancement is applied to the sensitive and selective analysis of three neutral glucosides: ginsenoside Rf, ginsenoside Rg1, and ginsenoside Re. Nonionic micelle detectability by CE is demonstrated through effective focusing of large sample volumes (up to 38% capillary length) using a dual sweeping mode. This results in a 50- to 130-fold improvement in the LODs relative to conventional injection method. Neutral compounds sweeping is examined in terms of analyte mobility dependence on borate complexation, solvent viscosity difference, and Brij-35 interaction. Enhanced focusing performance by this hyphenated method was demonstrated by a greater than fourfold reduction in glucoside bandwidth, as compared with common sweeping (devoid of organic solvent-mediated sweeping method in the sample matrices). Moreover, separation efficiencies greater than a million theoretical plates can be achieved by sweeping large sample volumes into narrow zones. The designated method was also tested for its ability to determine the presence of glucosides in the crude extracts obtained from plant sample.
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Affiliation(s)
- Jun Cao
- Key Laboratory of Modern Chinese Medicines (China Pharmaceutical University), Ministry of Education and Department of Pharmacognosy, China Pharmaceutical University, Nanjing, PR China
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Zhong GX, Li P, Zeng LJ, Guan J, Li DQ, Li SP. Chemical characteristics of Salvia miltiorrhiza (Danshen) collected from different locations in China. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2009; 57:6879-6887. [PMID: 19601629 DOI: 10.1021/jf901462s] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The chemical characteristics of Salvia miltiorrhiza , also called "danshen" in China, were investigated on the basis of the simultaneous quantitative determination of 13 hydrophilic and lipophilic compounds, namely, protocatechuic acid, protocatechuic aldehyde, caffeic acid, ferulic acid, isoferulic acid, rosmarinic acid, salvianolic acid B, salvianolic acid A, dihydrotanshinone I, przewalskin, cryptotanshinone, tanshinone I, and tanshinone IIA, in 74 samples collected from different locations using ultraperformance liquid chromatography (UPLC). Hierarchical clustering analysis based on 13 investigated compounds and the similarity of the entire chromatographic pattern showed that S. miltiorrhiza was significantly different from Salvia przewalskii , an adulterant of danshen. The chemical characteristics of S. miltiorrhiza collected from different locations in China were revealed, and salvianolic acid B, rosmarinic acid, cryptotanshinone, and tanshinones I and IIA were optimized as markers for the evaluation, which is helpful in the quality control of S. miltiorrhiza.
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Affiliation(s)
- Guo-Xin Zhong
- Institute of Chinese Medical Sciences, University of Macau, Macao SAR, China
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On-line concentration of neutral analytes by complexation and acetonitrile sweeping in nonionic microemulsion electrokinetic chromatography with direct ultraviolet detection. J Chromatogr A 2009; 1216:5608-13. [PMID: 19524933 DOI: 10.1016/j.chroma.2009.05.060] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Revised: 05/04/2009] [Accepted: 05/25/2009] [Indexed: 02/06/2023]
Abstract
To separate and detect neutral solutes in nonionic microemulsion electrokinetic chromatography (MEEKC), a novel method was developed, combining complex formation and acetonitrile (ACN) sweeping. In this report, dynamic borate complexation and on-line sweeping occurred simultaneously during a run. The operating parameters which affected the performance of analyte sweeping in nonionic MEEKC were examined in terms of borate complexation, ACN content, Brij-35 concentration and sample plug length. In addition, the validation of the method included tests of the limit of detection, reproducibility and sensitivity enhancement. 60-110-Fold of magnitude improvement in detection sensitivity for model compounds (ginsenoside Rf, ginsenoside Rb2, ginsenoside Re) using Brij-35 microemulsion was demonstrated. Furthermore, the method was applied to the determination of glucosides in the plant extract.
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Qi X, Wang S, Wu B, Qu H. Determination of Hepatotoxic Pyrrolizidine Alkaloids in Gynura segetum by MEKC. Chromatographia 2009. [DOI: 10.1365/s10337-009-1149-1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Cao J, Qi LW, Chen J, Li P. Pressure and electrokinetic injections for on-line sample stacking neutral analytes in microemulsion electrokinetic chromatography with salt-containing matrixes. Electrophoresis 2009; 29:4422-30. [PMID: 18942679 DOI: 10.1002/elps.200800190] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
An on-line technique for pressure and electrokinetic injections of long sample plugs with simultaneous stacking of neutral analytes (notoginsenoside R(1), ginsenoside Rg(1), ginsenoside Rf, ginsenoside Rh(1), ginsenoside Rd, ginsenoside Rg3) in microemulsion electrokinetic chromatography is presented. The effects of salt concentration, sample plug length, organic modification of the sample matrix, oil phase and SDS concentration on stacking efficiency were examined in order to optimize the two injection methods. In microemulsion electrokinetic chromatography, the effect of the type of oil and SDS content on stacking mechanism is often sophisticated. This study had demonstrated that the oil type and SDS content in microemulsion indeed markedly altered the affinity of microemulsion with analytes. Finally, in comparison with the electrokinetic injection method, the most apparent disadvantages of the pressure injection method were the relatively high LOD and poor reproducibility.
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Affiliation(s)
- Jun Cao
- Key Laboratory of Modern Chinese Medicines (China Pharmaceutical University), Ministry of Education, Nanjing, PR China
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Cao J, Qi LW, Liu EH, Zhang WD, Li P. Separation and on-line preconcentration by stacking and sweeping of charged analytes in the plant by microemulsion electrokinetic chromatography with nonionic surfactants. J Pharm Biomed Anal 2009; 49:475-80. [DOI: 10.1016/j.jpba.2008.10.016] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Revised: 10/07/2008] [Accepted: 10/09/2008] [Indexed: 10/21/2022]
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