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Journal articles on the topic 'Separation of basic compounds'

Author: Grafiati

Published: 4 June 2021

Last updated: 1 February 2022

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1

Wei, W., G. A. Luo, G. Y. Hua, and C. Yan. "Capillary electrochromatographic separation of basic compounds with bare silica as stationary phase." Journal of Chromatography A 817, no. 1-2 (August 1998): 65–74. http://dx.doi.org/10.1016/s0021-9673(98)00315-x.

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2

Stella, Cinzia, Patrick Seuret, Serge Rudaz, Pierre-Alain Carrupt, Jean-Yves Gauvrit, Pierre Lanteri, and Jean-Luc Veuthey. "Characterization of chromatographic supports for the analysis of basic compounds." Journal of Separation Science 25, no. 18 (December 1, 2002): 1351–63. http://dx.doi.org/10.1002/jssc.200290007.

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3

Asakawa, Yoshiki, Eiichi Yamamoto, and Naoki Asakawa. "Selective retention of basic compounds by metal aquo-ion affinity chromatography." Journal of Separation Science 37, no. 19 (August 11, 2014): 2641–51. http://dx.doi.org/10.1002/jssc.201400296.

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4

Petruczynik, Anna. "Analysis of alkaloids from different chemical groups by different liquid chromatography methods." Open Chemistry 10, no. 3 (June 1, 2012): 802–35. http://dx.doi.org/10.2478/s11532-012-0037-y.

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AbstractAlkaloids are biologically active compounds widely used as pharmaceuticals and synthesised as secondary methabolites in plants. Many of these compounds are strongly toxic. Therefore, they are often subject of scientific interests and analysis. Since alkaloids — basic compounds appear in aqueous solutions as ionized and unionized forms, they are difficult for chromatographic separation for peak tailing, poor systems efficiency, poor separation and poor column-to-column reproducibility. For this reason it is necessity searching of more suitable chromatographic systems for analysis of the compounds. In this article we present an overview on the separation of selected alkaloids from different chemical groups by liquid chromatography thus indicating the range of useful methods now available for alkaloid analysis. Different selectivity, system efficiency and peaks shape may be achieved in different LC methods separations by use of alternative stationary phases: silica, alumina, chemically bonded stationary phases, cation exchange phases, or by varying nonaqueous or aqueous mobile phase (containing different modifier, different buffers at different pH, ion-pairing or silanol blocker reagents). Developments in TLC (NP and RP systems), HPLC (NP, RP, HILIC, ion-exchange) are presented and the advantages of each method for alkaloids analysis are discussed.

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5

Geryk, Radim, Květa Kalíková, Martin G. Schmid, and Eva Tesařová. "Enantioselective separation of biologically active basic compounds in ultra-performance supercritical fluid chromatography." Analytica Chimica Acta 932 (August 2016): 98–105. http://dx.doi.org/10.1016/j.aca.2016.04.044.

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6

Kumar, Avvaru Praveen, and Jung Hag Park. "Chiral separation of basic compounds on a cellulose 3,5-dimethylphenylcarbamate-coated zirconia monolithin basic eluents by capillary electrochromatography." Journal of Chromatography A 1218, no. 37 (September 2011): 6548–53. http://dx.doi.org/10.1016/j.chroma.2011.06.101.

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7

Kalíková, Květa, Martina Riesová, and Eva Tesařová. "Recentchiral selectors for separation in HPLC and CE." Open Chemistry 10, no. 3 (June 1, 2012): 450–71. http://dx.doi.org/10.2478/s11532-011-0142-3.

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AbstractEnantiomers (stereoisomers) can exhibit substantially different properties if present in chiral environments. Since chirality is a basic property of nature, the different behaviors of the individual enantiomers must be carefully studied and properly treated. Therefore, enantioselective separations are a very important part of separation science. To achieve the separation of enantiomers, an enantioselective environment must be created by the addition of a chiral selector to the separation system. Many chiral selectors have been designed and used in various fields, such as the analyses of drugs, food constituents and agrochemicals. The most popular have become the chiral selectors and/or chiral stationary phases that are of general use, i.e., are applicable in various separation systems and allow for chiral separation of structurally different compounds. This review covers the most important chiral selectors / chiral stationary phases described and applied in high performance liquid chromatography and capillary electrophoresis during the period of the last three years (2008–2011).

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8

GUO, Zhi-Qing, Lei CHEN, and Qian-Hong WAN. "Endcapping of Octadecyl Bonded Silica by Atomic Layer Deposition for Separation of Basic Compounds." Chinese Journal of Analytical Chemistry 37, no. 11 (November 2009): 1572–76. http://dx.doi.org/10.1016/s1872-2040(08)60141-3.

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9

Ye, F., S. Li, and S. Zhao. "Electrochromatographic Evaluation of Diol-Bonded Silica Monolith Capillary Column for Separation of Basic Compounds." Journal of Chromatographic Science 47, no. 6 (July 1, 2009): 492–96. http://dx.doi.org/10.1093/chromsci/47.6.492.

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10

Ping, Guichen, Lihua Zhang, Lin Zhang, Weibing Zhang, Philippe Schmitt-Kopplin, Antonius Kettrup, and Yukui Zhang. "Separation of acidic and basic compounds in capillary electrochromatography with polymethacrylate-based monolithic columns." Journal of Chromatography A 1035, no. 2 (May 2004): 265–70. http://dx.doi.org/10.1016/j.chroma.2004.02.063.

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11

Stella, Cinzia, Serge Rudaz, Manuel Mottaz, Pierre-Alain Carrupt, and Jean-Luc Veuthey. "Analysis of basic compounds at high pH values by reversed-phase liquid chromatography." Journal of Separation Science 27, no. 4 (March 2004): 284–92. http://dx.doi.org/10.1002/jssc.200301671.

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12

VALETTE, J., A. BIZET, C. DEMESMAY, J. ROCCA, and E. VERDON. "Separation of basic compounds by capillary electrochromatography on an X-Terra RP18® stationary phase." Journal of Chromatography A 1049, no. 1-2 (September 17, 2004): 171–81. http://dx.doi.org/10.1016/s0021-9673(04)01216-6.

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13

Zhang, Kai, Chao Yan, Zhichao Zhang, Qinsun Wang, and Ruyu Gao. "Mixed Mode of Hydrophilic and Ionic Interaction Pressurized Capillary Electrochromatography for Separation of Basic Compounds." Journal of Liquid Chromatography & Related Technologies 26, no. 13 (August 2003): 2119–31. http://dx.doi.org/10.1081/jlc-120022397.

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14

Hong, Jong-Seong, and Jung Hag Park. "Chiral Separation of Basic Compounds on Sulfated β-Cyclodextrin-Coated Zirconia Monolith by Capillary Electrochromatography." Bulletin of the Korean Chemical Society 34, no. 6 (June 20, 2013): 1809–13. http://dx.doi.org/10.5012/bkcs.2013.34.6.1809.

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15

Guttman, Andr�s, Sandra Brunet, Caroline Jurado, and Nelson Cooke. "Rapid chiral separation methods development by cyclodextrin-mediated capillary electrophoresis for acidic and basic compounds." Chirality 7, no. 6 (1995): 409–14. http://dx.doi.org/10.1002/chir.530070605.

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16

Quang, Changyu, and Morteza G. Khaledi. "Extending the scope of chiral separation of basic compounds by cyclodextrin-mediated capillary zone electrophoresis." Journal of Chromatography A 692, no. 1-2 (February 1995): 253–65. http://dx.doi.org/10.1016/0021-9673(94)00999-p.

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17

Duke, CC, and RJ Wells. "Investigation of Readily Available Chiral Compounds for Preparative Scale Resolutions." Australian Journal of Chemistry 40, no. 10 (1987): 1641. http://dx.doi.org/10.1071/ch9871641.

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Diastereoisomeric esters were formed by reaction of racemic carboxylic acids with the readily available hydroxy lactone derivatives, 2,3-O-isopropylidene-D(+)-ribono-l,4-lactone, D(-)-2- hydroxy-3,3-dimethylbutyro-1,4-lactone (D(-)-pantolactone) and 1,2-O-isopropylidene-(+)-α-D-glucofuranurono-6,3-lactone. In all cases separation of the diastereoisomeric esters was achieved by crystallization and/or chromatography. Purity of the diastereoisomers could be determined by h.p.l.c. or by 1H n.m.r. Hydrolysis under mild basic conditions followed by treatment with acid gave optically pure carboxylic acids. The facile separation by crystallization and/or chromatography of diastereoisomers prepared from racemic endo-1,4,5,6,7,7-hexachlorobicyclo[2.2.l]hept-5-ene-2-carboxylic acid suggested that the resolved acid may be useful as a resolving agent. This was shown by separation of diastereoisomers formed from the resolved acid and racemic 1-(3′-phenoxyphenyl)prop-2- yn-1-ol and racemic 1-cyano-1-(3'-phenoxypheny1)methanol respectively. Optically pure 1-(3'-phenoxypheny1)prop-2-yn-1-ol was obtained by hydrolysis of the separated diastereoisomers.

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18

Liang, Chao, Shu-ying Han, Jun-qin Qiao, Hong-zhen Lian, and Xin Ge. "Determination of then-octanol/water partition coefficients of weakly ionizable basic compounds by reversed-phase high-performance liquid chromatography with neutral model compounds." Journal of Separation Science 37, no. 22 (October 13, 2014): 3226–34. http://dx.doi.org/10.1002/jssc.201400681.

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19

Ye, Fanggui, Zenghong Xie, Xiaoping Wu, Xucong Lin, and Guonan Chen. "Separation of Polar and Basic Compounds in Hydrophilic Interaction Pressurized CEC Using Diethylenetriaminopropyl Silica Monolithic Columns." Chromatographia 64, no. 5-6 (August 25, 2006): 267–72. http://dx.doi.org/10.1365/s10337-006-0022-8.

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20

Desiderio, Claudia, Zeineb Aturki, and Salvatore Fanali. "Use of vancomycin silica stationary phase in packed capillary electrochromatography I. Enantiomer separation of basic compounds." ELECTROPHORESIS 22, no. 3 (February 2001): 535–43. http://dx.doi.org/10.1002/1522-2683(200102)22:3<535::aid-elps535>3.0.co;2-8.

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21

Fanali, Salvatore, Zeineb Aturki, Giovanni D’Orazio, and Anna Rocco. "Separation of basic compounds of pharmaceutical interest by using nano-liquid chromatography coupled with mass spectrometry." Journal of Chromatography A 1150, no. 1-2 (May 2007): 252–58. http://dx.doi.org/10.1016/j.chroma.2006.10.021.

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22

Meyer, E., and H. Engelhardt. "Influence of residual silanol groups on the separation and asymmetry of basic compounds in RP-HPLC." Fresenius' Zeitschrift für analytische Chemie 333, no. 7 (January 1989): 734. http://dx.doi.org/10.1007/bf00476592.

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23

Kahiking, Gabriel Reinhard, Rymond Rumampuk, and Emma Pongoh. "Isolation and Identification Of Glycoside Compounds from n-Butanol Fraction of Red Pakoba (Syzygium sp.)." Fullerene Journal of Chemistry 5, no. 2 (October 26, 2020): 53. http://dx.doi.org/10.37033/fjc.v5i2.152.

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The red pakoba (Syzygium sp.) is a plant originating from north sulawesi that is often used by local people as a basic ingridient of medicine. This research was conducted to isolate and identify glycoside compounds contained in the n-butanol fraction of red pakoba fruits (Syzygium sp.). The isolation process was carried out using the maceration method, for the separation and purification of compounds using Thin Layer Chromatography (TLC) and Gravity Column Chromatography and obtained F2.4 sub-fraction isolates with a sample weight of 4.5 mg. Identification of compound using Proton Nuclear Magnetic Resonance (NMR-1H) and Carbon Nuclear Magnetic Resonance (NMR-13C) tecniques. The result of identification of isolate F2.4 sub-fraction as flavonoid glycoside compounds with the proposed name 3-O-methyl-butyrate-6,7,3',4' tetrahydroxy-5-methoxy-8-methyl flavan with molecular formula (C22H25O8)

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24

Wang, Fang, and Morteza G. Khaledi. "Capillary electrophoresis chiral separations of basic compounds using cationic cyclodextrin." Electrophoresis 19, no. 12 (September 1998): 2095–100. http://dx.doi.org/10.1002/elps.1150191209.

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25

Mazzoccanti, Giulia, Francesco Gasparrini, Andrea Calcaterra, Claudio Villani, and Alessia Ciogli. "Static vs. Dynamic Electrostatic Repulsion Reversed Phase Liquid Chromatography: Solutions for Pharmaceutical and Biopharmaceutical Basic Compounds." Separations 8, no. 5 (May 2, 2021): 59. http://dx.doi.org/10.3390/separations8050059.

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Many efforts have been made to separate basic compounds, which are challenging to resolve in reversed phase liquid chromatography. In this process, they are strongly retained and the peak shape undergoes significant distortion. The principal origin of this has been identified with the non-negligible interaction with residual deprotonated silanols. Consequently, all solutions that efficiently shield silanols are being sought. This review is an upgrade on the use of the electrostatic repulsion reversed phase (ERRP) approach: retention of bases, in protonated form, can be achieved by modulating the charge repulsion caused by the presence of positive charges in the chromatographic system. This study successfully (i) introduced fixed positive charges in the structure of stationary phases, (ii) used cationic and hydrophobic additives in the mobile phase, and (iii) used the ERRP-like approach employed at the preparative level for peptide purification.

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26

Lelekov, Alexander S., and Rudolf P. Trenkenshu. "Basic principles of modeling microalgae's photobiosynthesis." Issues of modern algology (Вопросы современной альгологии), no. 3(18) (2018): 1–10. http://dx.doi.org/10.33624/2311-0147-2018-3(18)-1-10.

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The paper lists the classic and modern views on the microalgae's culture growth, which constitute a new paradigm of modeling photobiosynthesis. Microalgae are considered as lower obligate photoautotrophs capable of oxygenic photosynthesis, characterized by the separation of photochemical and enzymatic processes. A model scheme of the light and dark reactions conjugation in microalgae is proposed. The process of biosynthesis of cell biochemical structures from minerals is carried out due to the energy of high-potential forms of high-energy compounds (NADP·H, ATP). It is shown that the microalgae's growth can be considered as a set of energyexchange reactions. The concept of the absence of limiting microalgae's growth by environmental factors is proposed. The rate of biomass synthesis is determined by the reduced flow density of the energy or plastic substrate to the key enzyme. Also, for convenience in practical terms, productivity can be expressed through the biochemical measured ratio of structural and reserve forms of biomass. In any case, the dependence of the rate of biomass synthesis on the value of the reduced flux density is described by linear splines, which allows you to clearly set the switching point of the limiting factor and obtain simple mathematical solutions.

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27

Stella, Cinzia, Alexandra Galland, Xiangli Liu, Bernard Testa, Serge Rudaz, Jean-Luc Veuthey, and Pierre-Alain Carrupt. "Novel RPLC stationary phases for lipophilicity measurement: Solvatochromic analysis of retention mechanisms for neutral and basic compounds." Journal of Separation Science 28, no. 17 (November 2005): 2350–62. http://dx.doi.org/10.1002/jssc.200500104.

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28

Jiang, Yin Ju, Zeng Wu Zhao, Zhang Yin Xu, and Bao Wei Li. "Enriching Valuable Elements in Tailings Re-Concentration of Bayan Obo Mine by Direct Reduction." Advanced Materials Research 476-478 (February 2012): 236–40. http://dx.doi.org/10.4028/www.scientific.net/amr.476-478.236.

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For the re-concentration minerals of RE dressing tailings in Bayan Obo mine, Fe and P compounds were selectively reduced by the methods of coal-based direct reduction in reactionary pot. The metal and slag in sponge iron obtained from reduction was melted and separated. Compared to that in re-concentration minerals, the content of valuable elements oxide in melt-separation slag was enriched to about 2.5 times. Therefore, melt-separation slag can be used as the basic material to extract the valuable elements.

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29

Hu, Jiwei, Chuanhui Xie, Ruijun Tian, Zhike He, and Hanfa Zou. "Separation of basic and acidic compounds by capillary electrochromatography using monolithic silica capillary columns with zwitterionic stationary phase." Journal of Separation Science 30, no. 6 (April 2007): 891–99. http://dx.doi.org/10.1002/jssc.200600173.

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30

Amarowicz, R., R. B. Pegg, and A. Kosińska. "SE-HPLC separation of myosin complex with tannins from bearberries (Arctostaphylos uva-ursi L. Sprengel) leaves – a short report." Czech Journal of Food Sciences 27, No. 5 (October 28, 2009): 386–91. http://dx.doi.org/10.17221/234/2008-cjfs.

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Phenolic compounds were extracted from bearberry (<i>Arctostaphylos uva-ursi</i> L. Sprengel) leaves into 95% (v/v) ethanol. The tannin constituents were separated from the crude extract using Sephadex LH-20 column chromatography with 95% (v/v) ethanol and 50% (v/v) acetone as the mobile phases. Myosin was isolated and purified from excised pork knuckle muscles using the standard salt-solution extraction procedure followed by gel filtration chromatography. Myosin was precipitated from the solution with bearberry-leaf tannins at pH 5.0. The recovered complex was washed, lyophilised, and subjected to size-exclusion high performance liquid chromatography (SE-HPLC). Based on the basic conditions of the HPLC analysis, a portion of the tannin constituents was liberated from the complex. The UV spectra of these compounds were characterized by a maximum at ~ 300 nm. A portion of the tannins was present in the complex with myosin, and this was confirmed by UV spectra.

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31

Hou, Yucui, Zhi Feng, Jaime Ruben Sossa Cuellar, and Weize Wu. "Separation of phenols from oils using deep eutectic solvents and ionic liquids." Pure and Applied Chemistry 92, no. 10 (October 25, 2020): 1717–31. http://dx.doi.org/10.1515/pac-2019-1119.

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AbstractPhenolic compounds are important basic materials for the organic chemical industry, such as pesticides, medicines and preservatives. Phenolic compounds can be obtained from biomass, coal and petroleum via pyrolysis and liquefaction, but they are mixtures in oil. The traditional methods to separate phenols from oil using alkaline washing are not environmentally benign. To solve the problems, deep eutectic solvents (DESs) and ionic liquids (ILs) have been developed to separate phenols from oil, which shows high efficiency and environmental friendliness. In this article, we summarized the properties of DESs and ILs and the applications of DESs and ILs in the separation of phenols and oil. There are two ways in which DESs and ILs are used in these applications: (1) DESs formed in situ using different hydrogen bonding acceptors including quaternary ammonium salts, zwitterions, imidazoles and amides; (2) DESs and ILs used as extractants. The effect of water on the separation, mass transfer dynamics in the separation process, removal of neutral oil entrained in DESs, phase diagrams of phenol + oil + extractant during extraction, are also discussed. In the last, we analyze general trends for the separation and evaluate the problematic or challenging aspects in the separation of phenols from oil mixtures.

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32

Li, Lai‐Sheng, Shi‐Lu Da, Yu‐Qi Feng, and Min Liu. "HPLC Separation of Neutral, Acidic, and Basic Compounds on ap‐tert‐Butyl‐calix[8]arene‐bonded Stationary Phase." Analytical Letters 37, no. 13 (December 27, 2004): 2805–17. http://dx.doi.org/10.1081/al-200032073.

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33

Long, Zhen, Dongping Yu, Yanfang Liu, Nana Du, Yanduo Tao, Lijuan Mei, Zhimou Guo, and Xinmiao Liang. "The influence of organic sample solvents on the separation efficiency of basic compounds under strong cation exchange mode." Analytica Chimica Acta 872 (May 2015): 77–83. http://dx.doi.org/10.1016/j.aca.2014.12.057.

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34

Long, Zhen, Zhimou Guo, Xingya Xue, Xiuli Zhang, Lilly Nordahl, and Xinmiao Liang. "Selective separation and purification of highly polar basic compounds using a silica-based strong cation exchange stationary phase." Analytica Chimica Acta 804 (December 2013): 304–12. http://dx.doi.org/10.1016/j.aca.2013.10.034.

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35

Zhang, Zhiping, Yajun Zheng, Jixiu Zhang, Jiping Chen, and Xinmiao Liang. "Magnesium oxide microspheres as a packing material for the separation of basic compounds in normal-phase liquid chromatography." Journal of Chromatography A 1165, no. 1-2 (September 2007): 116–21. http://dx.doi.org/10.1016/j.chroma.2007.07.072.

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36

Rowland, Steven M., Winston K. Robbins, Alan G. Marshall, and Ryan P. Rodgers. "Characterization of Highly Oxygenated and Environmentally Weathered Crude Oils by Liquid Chromatography Fourier Transform Ion Cyclotron Mass Spectrometry (FT-ICR MS)." International Oil Spill Conference Proceedings 2014, no. 1 (May 1, 2014): 300205. http://dx.doi.org/10.7901/2169-3358-2014-1-300205.1.

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Heavy and biodegraded oils exhibit an ever increasing oxygen complexity. Electrospray ionization (ESI) coupled to FT-ICR MS highlights the most acidic and basic oxygen species; however, quantitative and qualitative information about less polar oxygenated compounds is essential to understand both the source and, potentially, the modification pathways for oxygenated crude oils. Liquid chromatography (LC) is complementary to FT-ICR MS to deconvolve crude oils according to oxygen functionality, thereby enriching oxygen species that are not easily ionized or are present in low abundance. Ketones and carboxylic acids dominate most environmentally modified crude oils; however, phenols and polyphenols are also important intermediates in both biotic and abiotic modifications. Moreover, due to the nature of the refinement process, oxygen-containing species and their intermediates can serve as chemical tracers in produced water streams and areas of rapid thermal changes that lead to gum or deposit formation. Here, we describe an analytical separation scheme for an environmentally weathered (highly oxygenated) crude oil designed to highlight carboxylic acid isolation and ketone enrichment, as well as the separation of other oxygen compounds by polarity. Experimental A weathered beach extract collected from the coast of Florida was fractionated by LC and analyzed by FT-ICR MS. LC techniques are designed to target specific oxygen functionalities (e.g., ketones, alcohols, phenols, and carboxylic acids). The mass spectra of the LC fractions were acquired with a custom-built 9.4 T FT-ICR Instrument. Positive and negative electrospray ionization serve to highlight basic and acidic oxygen species. Preliminary DataLC fractionation was performed with a silicic acid stationary phase. Four fractions correspond to aromatics, neutral nitrogen, basic nitrogen, and polar compounds. Positive ESI FT-ICR MS indicated a relative abundance for the O1 heteroatom class ranging from 2% in the whole beach extract to 12 % in the neutral nitrogen fraction. The increased relative abundance of O1 compounds suggests the enrichment of ketones from the original sample. Carboxylic acids are isolated by retention on an amine stationary phase and subsequent elution with a mixture of dichloromethane, methanol, and formic acid. Oxygen species will be further probed with new separation schemes to focus on analysis of phenols.

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37

Li, Xiong, Yu Feng Zhang, Liu Yang, Yi Feng, Yuan Hui Deng, Yi Ming Liu, and Xing Zeng. "Chemical Profiling of Constituents of Smilacis glabrae Using Ultra-high Pressure Liquid Chromatography Coupled with LTQ Orbitrap Mass Spectrometry." Natural Product Communications 7, no. 2 (February 2012): 1934578X1200700. http://dx.doi.org/10.1177/1934578x1200700213.

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A reliable LC-MS method has been applied for the separation and identification of major constituents of the rhizome of Smilacis glabrae. Identification of the constituents was carried out by interpretation of their retention time, and MS and MS/MS data, especially by comparing these with Sarcandra glabra under the same LC-MS conditions, as well as the data provided by the literature. Thirty-three compounds, including catechin derivatives, flavanonols, phenolic acid derivatives and phenylpropanoid glycosides were either identified or tentatively characterized. Among them, compound 12 was deduced to be a new phenylpropanoid-substituted catechin. Fragmentation behaviors of the three major categories of compounds were also investigated. This UPLC-PDA/ESI-MSnmethod was effective for the separation and identification of the constituents and could be the basis for the comprehensive quality control of Smilacis glabrae.

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38

Nojavan, Saeed, Arezoo Moharami, and Ali Reza Fakhari. "Two-step liquid phase microextraction combined with capillary electrophoresis: A new approach to simultaneous determination of basic and zwitterionic compounds." Journal of Separation Science 35, no. 15 (July 2, 2012): 1959–66. http://dx.doi.org/10.1002/jssc.201200229.

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39

Lurie, Ira S., Timothy S. Conver, and Valerie L. Ford. "Simultaneous Separation of Acidic, Basic, and Neutral Organic Compounds, Including Strong and Moderate Acids and Bases, by Capillary Electrochromatography." Analytical Chemistry 70, no. 21 (November 1998): 4563–69. http://dx.doi.org/10.1021/ac9804543.

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40

DeBot, S. Ann, John R. Jezorek, and Michael E. Hager. "Liquid chromatographic separation of several classes of acidic and basic aromatic compounds on silica-bonded 8-quinolinol stationary phases." Journal of Chromatography A 465, no. 3 (1989): 249–62. http://dx.doi.org/10.1016/s0021-9673(01)92663-9.

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41

Servais, Anne-Catherine, Marianne Fillet, Adel M. Abushoffa, Philippe Hubert, and Jacques Crommen. "Synergistic effects of ion-pairing in the enantiomeric separation of basic compounds with cyclodextrin derivatives in nonaqueous capillary electrophoresis." ELECTROPHORESIS 24, no. 3 (February 2003): 363–69. http://dx.doi.org/10.1002/elps.200390046.

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42

Long, Zhen, Chaoran Wang, Zhimou Guo, Xiuli Zhang, Lilly Nordahl, and Xinmiao Liang. "Strong cation exchange column allow for symmetrical peak shape and increased sample loading in the separation of basic compounds." Journal of Chromatography A 1256 (September 2012): 67–71. http://dx.doi.org/10.1016/j.chroma.2012.07.008.

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43

Delpino-Rius, Antoni, Jordi Eras, Ferran Gatius, Mercè Balcells, and Ramon Canela-Garayoa. "Combined Analysis of Primary Metabolites and Phenolic Compounds to Authenticate Commercial Monovarietal Peach Purees and Pear Juices." Molecules 24, no. 18 (September 10, 2019): 3289. http://dx.doi.org/10.3390/molecules24183289.

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Here we authenticated single-varietal peach purees and pear juices on the basis of primary metabolite and phenolic compound analysis by Proton Nuclear Magnetic Resonance (1H-NMR) and Ultra Performance Liquid Chromatography coupled to Photodiode Array and Tandem Mass Spectrometry (UPLC-PDA-MS/MS), respectively. After suitable preprocessing, the 1H-NMR and chromatographic data were evaluated by principal component analysis (PCA). The PCA combining data from primary metabolites and phenolic compounds allowed the separation of the clusters in all cases, allowing discrimination of processed and unprocessed peach purees, both separately and pooled. The PCA of primary metabolites allowed the cluster separation of purees of distinct peach varieties but not between processed and non-processed purees. The PCA of phenolic compounds allowed better cluster separation than of primary metabolites. For pear juices, both PCA approaches allowed satisfactory discrimination of Alejandrina, Conference, and Blanquilla cultivars. These approaches may help to better control cultivar authenticity in fruit products. It could therefore contribute to the development of a process to achieve products characterized by a quality characteristic of a given cultivar.

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Jain, Rakesh, Megh Singh, and David J. Dezman. "Qualitative and Quantitative Characterization of Phenolic Compounds from Lantana (Lantana camara) Leaves." Weed Science 37, no. 3 (May 1989): 302–7. http://dx.doi.org/10.1017/s0043174500071964.

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Phytotoxins from lantana leaves were extracted in aqueous media adjusted to pH 4, 7, or 10. All three leaf extracts showed considerable phytotoxic activity in duckweed growth bioassay. The acidic and the neutral extracts of lantana leaves at 10 g fresh weight/L were more phytotoxic to duckweed growth than the alkaline extract at the same concentration. Phenolic compounds present in lantana leaves were isolated by alkaline hydrolysis of the crude leaf extracts followed by separation of the various components in ether or aqueous media. The fraction containing the phenolics showed considerable phytotoxic activity against duckweed growth. In addition, the fraction containing the nonpolar substances separated from the acidic and the neutral crude extracts also showed significant phytotoxic activity against duckweed growth. No attempt was made to isolate and identify the phytotoxic component from the nonpolar fraction. Characterization of the phenolic fraction by HPLC revealed the presence of at least 14 phenolic compounds. All three leaf extracts contained the same array of phenolic compounds. However, the quantity of phenolic compounds extracted varied with the pH of the extraction medium. The acidic extract containedp-hydroxybenzoic acid (0.09 mM) as the most abundant phenolic compound, whereas the neutral and the basic extracts containedp-coumaric acid (0.11 and 0.26 mM, respectively) as the most abundant phenolic compound. All phenolic compounds, exceptp-hydroxybenzoic acid, proved phytotoxic to duckweed growth at a concentration of 1 mM or lower. Salicylic acid was the most phytotoxic of the phenolic compounds detected in lantana leaf extracts. The phytotoxicity of lantana leaf extracts is probably partly due to a complex interaction of all phenolic compounds present.

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Bystrický, Slavomír, Izabela Medovarská, and Eva Machová. "Separation of Different Types of Monosaccharides by Polyacrylamide Column Chromatography." Zeitschrift für Naturforschung B 66, no. 3 (March 1, 2011): 295–98. http://dx.doi.org/10.1515/znb-2011-0312.

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A high-throughput polyacrylamide gel chromatography was effectively tested to separate different types of monosaccharides. These occur for example in the complex bacterial LPS (lipopolysaccharide) structures as well as in other compounds. Here, a Bio-Gel P-2 column eluted only with water at ambient temperature afforded a convenient separation of the main structural types of neutral, charged, or highly polar hexoses, as well as N-acetylated hexose derivatives. These can be easily isolated on the semi-preparative scale by this method. The method was evaluated with a mixture of all basic types of monosaccharides, and repeatedly an efficient resolution was achieved. As an example of a complex structure, the monosaccharide constituents of the delipidated bacterial lipopolysaccharides (dLPS) of V. cholerae O135 were effectively separated after acid hydrolysis.

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Pawęska, K., and B. Malczewska. "Nitrogen compounds in drain sewage after constructed wetlands." Water Science and Technology 60, no. 10 (November 1, 2009): 2613–19. http://dx.doi.org/10.2166/wst.2009.620.

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Constructed wetlands, commonly known as ground filters, are well suited mostly for wastewater treatment in areas with no central sewage system. The basic difficulty with exploitation of constructed wetlands is connected with irregular hydraulic overload of its surface. However, irregular wastewater inflow can be reduced by cyclical irrigation which increases efficiency. The unquestionable advantage of the constructed wetlands is inexpensive construction and exploitation as well as low energy consumption. The constructed wetlands also fit very well in surrounding area. The investigation concerned the analysis of two constructed wetlands which are composed of mechanical separation (septic tank) and a filter bed with subsurface flow. The research has been undertaken in a period from July to December 2008, with regard to concentration distribution of nitrogen compounds in municipal sewage after constructed wetlands. The preliminary investigation on constructed wetland which has been exploited for 10 years showed variable removal efficiency of nitrogen compounds. The continuation of the research can indicate the efficiency of wastewater treatment in summer and winter season.

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Li, Yan, Shi-Wei Sun, Xiao-Yi Zhang, Yang Liu, Xiao-Hong Liu, Shuang Zhang, Wei Wang, Jin Wang, and Wei Wang. "Separation of New Coumarin Glycosides from Toddalia asiatica Using Offline Two-Dimensional High-Performance Liquid Chromatography." Plants 9, no. 4 (March 31, 2020): 428. http://dx.doi.org/10.3390/plants9040428.

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Coumarins and flavonoids are the major constituents of Toddalia asiatica. The separation and purification of ingredients from T. asiatica is an important procedure to acquire high-purity compounds for subsequent pharmacological investigation to discover leading compounds. In the present work, an offline two-dimensional high-performance liquid chromatography (HPLC) method was successfully established for the separation of high-purity glycosides from T. asiatica. Based on the separation results obtained with two different chromatographic stationary phases, a phenyl-bonded silica-based reversed-phase column was employed as the first HPLC preparation, and three fractions were obtained from the sample. Then, the fractions were isolated and purified on an octadecyl-bonded silica-based reversed-phase column to obtain high-purity compounds in the second HPLC separation. As a result, three coumarin glycosides, including two undescribed and one known, along with one known flavonoid glycoside with more than 98% purity were isolated from the sample. The structures of the isolated compounds were elucidated on the basis of extensive spectroscopic evidence derived from optical rotation, mass spectrometry, and nuclear magnetic resonance experiments. Two-dimensional HPLC with different stationary phases has the potential to be an efficient method for the separation of high-purity compounds from T. asiatica.

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Čejka, Jan, Richard Kubík, Bohumil Kratochvíl, and Josef Kuthan. "Sterically Crowded Heterocycles. VI. Relative Configuration of Diastereoisomeric (Z)-1,3-Diphenyl-3-(5-methyl-2-phenylimidazo[1,2-a]pyridin-3-yl)prop-2-en-1-ols." Collection of Czechoslovak Chemical Communications 61, no. 9 (1996): 1380–85. http://dx.doi.org/10.1135/cccc19961380.

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Relative configuration of the titled racemic compounds 1a and 1b has been elucidated on the basis of a complete X-ray structure determined for the higher melting diastereoisomer. The compound 1a crystallizes in the orthorhombic space group P21212, a = 15.610(3) Å, b = 18.634(4) Å, c = 7.5672(7) Å, V = 2201.1(6) Å3, Z = 4. Preparative separation of both diastereoisomers is reported.

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McCalley, David V. "Selection of suitable stationary phases and optimum conditions for their application in the separation of basic compounds by reversed-phase HPLC." Journal of Separation Science 26, no. 3-4 (March 1, 2003): 187–200. http://dx.doi.org/10.1002/jssc.200390026.

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Wang, Yuxiao, Zhenzhen Xu, Yue Wu, Mo Li, Sicheng Pang, Zhe Liang, and Yuanying Ni. "Effect of Weakly Basic Conditions on the Separation and Purification of Flavonoids and Glycosides from Chrysanthemum morifolium Tea." Molecules 24, no. 2 (January 15, 2019): 297. http://dx.doi.org/10.3390/molecules24020297.

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Tea brewed from chrysanthemum flowers has been widely used in Chinese medicine. The possibly medicinal compounds in Chrysanthemum morifolium tea can be purified by preparative high performance liquid chromatography (HPLC), but this is usually done with acidic conditions, which leads to the hydrolysis of glycosides. In hopes of avoiding this hydrolysis, we explored the effect of weakly basic conditions on the separation and purification of flavonoids and glycosides from Chrysanthemum morifolium. We also explored the effects of weakly basic conditions on chlorogenic acid (3-CQA) and apigenin-7-O-glucoside (A7G). Our results show that the concentration of the weakly basic ammonium hydrogen carbonate and time had no significant effect on A7G, p < 0.01, but it had a significant effect on 3-CQA, p < 0.01. HPLC and ultraviolet (UV) analysis showed that the structure of 3-CQA is destroyed in weakly basic conditions. Caffeic acid, quinic acid, and 3,4-dihydroxymandelic acid, which is a hydrolysate of 3-CQA, were identified by ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-Q-TOF-MS). The results showed that weakly basic conditions could be used for the purification of flavonoids and glycosides but not for caffeoylquinic acids. Moreover, our work clarified the hydrolysis behaviour of caffeoylquinic acids, which can be helpful for research into their functional aspects.

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