Non-polar Eluent Research Articles

Phytochemistry and Cytotoxicity Analysis of Kemang (Mangifera kemanga) Fruit Extract on HeLa Cervical Cancer Cell Line

Mango extract has been proven in its anticancer effect against cervical cancer, however kemang (Mangifera kemanga), despite being a relative of mango, has not been thoroughly researched although expected to give the same effect. Objective: To identify the contents contained in the ethanol, ethyl acetate, and n-hexane extract of kemang flesh and examine its cytotoxic effect on HeLa cervical cancer cells. Methods: Kemang flesh was extracted using ethanol, ethyl acetate, and n-hexane. Phytochemical tests and thin-layer chromatography on the extracts were conducted to identify the phytochemical contents. MTT assay was carried out using the extracts against HeLa cells to find out the cytotoxic effect of the samples in IC50 values. Results: Phytochemical tests revealed that kemang flesh extract contains flavonoid, tannin, triterpenoid, and alkaloid. Thin-layer chromatography test with nonpolar eluent showed one spot with Rf of 0.82 in ethanol extract; six spots with Rf of 0.16, 0.36, 0.49, 0.76, 0.82, and 0.94 in ethyl acetate extract; and six spots with Rf of 0.36, 0.48, 0.63, 0.75, 0.83, and 0.93 in n-hexane extract. MTT assay obtained IC50 values for HeLa cells, respectively for ethanol, ethyl acetate, and n-hexane extracts, were 44.34, 16.41, and 43.23ppm. Conclusion: Kemang fruit extract has potential as an anticancer agent against cervical cancer.

Roll‐to‐Roll Gravure‐Printed Carbon Nanotube‐based Transistor Arrays for a Digital Column Chromatograph

AbstractRoll‐to‐roll (R2R)‐printed thin‐film transistor‐based devices have apparent advantages over their silicon‐based counterparts to explore a new device concept where form factor and cost are critical. Here, the R2R gravure‐printed single‐walled carbon nanotube (SWCNT)‐based thin‐film transistor (TFT) arrays are demonstrated to show advantages in developing inexpensive digital column chromatography (DiCC). The DiCC can be easily constructed by cutting and pasting the fluoropolymer, CYTOP, coated R2R gravure‐printed SWCNT‐TFT arrays on the inside wall of the column. The coated CYTOP acts as an electret and induces charges depending on dipole moments of the molecules in nonpolar eluents. Since the induced charges act as an n‐type dopant to the printed p‐type SWCNT‐TFT, the off‐currents of SWCNT‐TFT arrays are raised when analyte molecules with a dipole moment move to the CYTOP‐coated SWCNT‐TFT. By monitoring the off‐current variations of the CYTOP‐coated SWCNT‐TFT, the flow of molecules can be digitally monitored, and even the structural isomers of molecules can be digitally differentiated in real time.

Potensi Tumbuhan Kelakai (Stenochlaena palustris (Burm.F.) Bedd.) asal Kalimantan Tengah sebagai Afrodisiaka

The necessity of traditional medicine is efficacious as aphrodisiac increasing every year. The Dayak community believes that Kelakai roots have efficacy as an aphrodisiac drug, but no studies were conducted relating to the efficacy of the Kelakai roots. Traditional medicinal products are efficacious as aphrodisiac have a hormone-like effect, usually contain active ingredients that have estrogenic properties among other things, progesterone, androgenic, adaptogenic, and ketogenic. Materials that are androgenic or adaptogenic nature helps maintain and restore stamina. This research was aimed to determine the content of the active compound on the Kelakai roots that efficacious as an aphrodisiac and to determine the profile of Thin Layer Chromatography (TLC) of active compound contained in Kelakai roots. This study used the identification method of chemical compounds such as starches and aleurone, tannins, catechols, flavonoids, alkaloids, saponins, and steroids for simplicia powder and ethanol extract of Kelakai roots. The extraction of Kelakai roots done by soxhletation and TLC used to identify a specific chemical compound. The result showed that Kelakai Roots contain active compounds potentially aphrodisiac namely alkaloids and saponin. While the TLC profile obtained is the presence of stains on the appearance of a non-polar eluent (Chloroform: Ethyl Acetate) with a ratio of 7: 3, 8: 2, 9: 4 with each Rf value is 0.70 cm (7: 3), 0.94 cm (8: 2) and 0.94 cm (9: 4). This research reported for the first time the potential of Kelakai roots as an aphrodisiac. Thus, further work will focus on the study of the pharmacological effects of Kelakai roots.

Structural Elucidation of secondary Metabolites in Sponge (Callyspongia pseudoreticulata) with N-Hexane Extract

Sponge is one of the marine species that has a high bioactivity and contains secondary metabobolite compound which can be used as antibiotic and medicine. Terpenoid compound derivatives have been successfully isolated from sponge Callyspongia pseudoretilulata by a method in which the n-hexane extract weighing 11.28 g was fractionated using vacuum column chromatography with a non-polar eluent, n-hexane. The polarity of this eluent was improved by ethyl acetic resulting in fairly polar eluent, methanol. A total of 27 fractions were obtained and one of the compounds from n-hexane extract was structurally elucidated by NMR spectroscopy and two dimensions of homonuclear and heteronuclear (1H, 13C, DEPT, H-H COSY, HMQC, and HMBC). The identified compound was a hydrocarbon (1-ethyl cyclo hex cosana-1-amin) that indicated LC50 of 60.58 against A. salina and has a great potential as antitumor or anticancer.

Method Development for Chiral Purification of Racemic Clopidogrel using Chiral Stationary Phase

HPLC method was developed for resolution of racemic clopidogrel into its chirally pure enantiomer of interest. Screening experiments were performed using amycoat and cellucoat analytical chiral stationary phases in organic solvent based polar and nonpolar eluents in various combinations. Based on the screening outcomes, the compound loading studies were carried out using amycoat higher μ particle sized chiral stationary column by keeping in mind the scale up studies to avoid high back pressure that can limit the efficiency of separation.

Separation of Lipid Classes by HPLC on a Cyanopropyl Column

A new method for the separation and identification of lipid classes by normal-phase HPLC on a cyanopropyl column is described. The use of a simple binary gradient, with toluene as a component, provided a rapid separation of non-polar as well as phospholipid classes. The inherent small differences in performances between possible non-polar eluent components of the gradient, such as hexane, heptane, and iso-octane, had a pronounced impact on retention times for individual phospholipid classes. Separation of molecular species within a lipid class could also be observed.

UTILIZATION OF ACTIVATED ZEOLITE AS MOLECULAR SIEVE IN CHROMATOGRAPHIC COLUMN FOR SEPARATION OF COAL TAR COMPOUNDS

Application of activated zeolite (ZAA) as molecular sieve to separate compounds of coal tar from vaccum fractional distillation, have been done. The size of zeolite was 10-20 mesh and used as solid phase in column chromatography with length of 30 cm. The first step of the research was coal pyrolisis and the product (tar) was distillated by fractional column and vaccum system at reduced pressure 44 cmHg and maximum temperature at 200 oC. The distillate from this procedure was flowed to the column chromatography of zeolite (ZAA). The compound absorbed by zeolite was eluted with varying solvents, i.e: CCl4, acetone and ethanol. Each fraction was then analyzed by gas chromatography. The results showed, zeolite have a capability to separate the compounds of tar and it tends to absorb medium hydrocarbon. The nonpolar eluent [CCl4] gives the better result in eluting tar compound than polar (ethanol) or medium polar eluents (acetone). Keywords: zeolite, coal tar, column chromatography

Effect of octabromination of a tetrakis(4-carboxyphenyl)porphine derivative bound to silica gels on HPLC retention behaviors of polyaromatic hydrocarbons

The effect of bromination of Cu-porphyrin-derivative-immobilized silica gels (Cu-TCPP D) was examined by comparing the retention behaviors of polyaromatic hydrocarbons (PAHs) on Cu-TCPP D and Cu-octabromotetrakis(4-carboxyphenyl)porphine-derivative-immobilized silica gels (Cu-OBTCPP D) columns. It was revealed that bromination affects strongly the π–π electron interactions caused from hydration energy in a polar eluent (80% methanol) possibly as a result of a destruction of planar structure of porphine-ring by bromination. It was also revealed that bromination enhances π–d interactions as well as the π–π electron interactions in a broad sense (e.g., dispersion forces) in a non-polar eluent ( n-hexane). However, the bromination did not exert much influence on electrostatic interactions caused from polarization of mono-halogenated benzenes.

HPLC Retention Behaviors of Poly-aromatic-hydrocarbones on Cu(II)-octabromotetrakis(4-carboxyphenyl)porphine Derivatives-Immobilized Aminopropyl Silica Gels in Polar and Non-Polar Eluents

As one of approaches of developing novel HPLC stationary phases, we prepared Cu-octabromotetrakis(4-carboxyphenyl)porphine derivative-immobilized silica gels (Cu-OBTCPP(D)), and evaluated the availability of the resultant Cu-OBTCPP(D) as a stationary phase for separation of poly-aromatic-hydrocarbons (PAHs) and their related compounds. A Cu-OBTCPP(D) column was revealed to have an ability to separate simple PAHs and be useful as a stationary phase in both polar and non-polar eluents. The retention property of the Cu-OBTCPP(D) column was evaluated in various comparative experiments using commercially available columns. In comparison with 2-(1-pyrenyl)ethyl dimetylsilyl silica gel column (PYE column) regarding the retention behavior for PAHs etc., the Cu-OBTCPP(D) column showed stronger interactions involving pi electron in non-polar eluent than PYE column. In comparison with a pentabromobenzyloxy propylsilyl silica gel column (PBB column) regarding the influence of bromination, the Cu-OBTCPP(D) column was affected differently from the PBB column. In comparison with nitrophenylethyl silica gel column (NPE column) regarding the retention behavior for compounds having a dipole in a non-polar eluent, the Cu-OBTCPP(D) column showed electrostatic interactions such as dipole-dipole interaction equivalent to or larger than the NPE column.

π-Electron interaction of PAHs with anion-exchange silica gels modified with anionic metal-porphine and -phthalocyanine derivatives as HPLC stationary phase for preparative column in organic solvents

To develop easy-to-prepare stationary phases for HPLC, we investigated anion-exchange silica gels, Nucleosil 5SB (Nuc), modified with metal-porphines and -phthalocyanines (M-P). The modified silica gels (M-PN) were evaluated for the availability as a stationary phase of HPLC for the separation of π-electron-rich polyaromatic hydrocarbons (PAHs) in polar and non-polar eluents. Separation ability of silica gels modified with Cu-phthalocyanine derivative (Cu-PCSN) was comparable to that of the silica gels binding Cu-PCS through sulfonamide bonds; however, the latter requires troublesome procedures for the preparation. The PAHs tested interact with Cu-PCSN in non-polar organic eluents through their π-electrons similarly as in the case of the PYE column®, in which interaction with PAHs was reported to be only the π–π-electron interaction.

Selectivity of electron-donor- and electron-acceptor-bonded silica packing materials for hydrophobic environmental contaminants in polar and non-polar eluents

Electron-acceptor-bonded stationary phases, 2-(nitrophenyl)-ethylsilyl (NPE) 3-( p-nitrophenoxy)propylsilyl (NPO), and electron-donor-bonded phases, 3-(N-carbazolyl)propylsilyl (CZP), 2-(1-pyrenyl)ethylsilyl (PYE), and 5-coronenylpentysilyl (COP), were prepared from silica particles and their selectivities were examined in both polar and non-polar solvents for specific isomers of polychlorodibenzo- p-dioxins (PCDDs), hexachloronaphthalenes (HxCNs) and planar and non-planar polychlorobiphenyl (PCB) congeners. Although no single stationary phase was able to separate all the isomer pairs that are coproduced during the synthesis of the PCDDs and HxCNs, pairs can be separated by selecting a suitable stationary phase and solvent. The separation of mixtures of PCDD isomers were found to be most successful with PYE and NPO phases, which yielded the opposite elution orders for each isomer pair that is produced as a mixture. Similar results were obtained for the HxCN isomers that were separated on PYE and CZP phases. The COP phase provided easier separation of non- ortho-substituted and mono- ortho-substituted PCBs from the other PCBs based on the planarity than PYE phase.

Separation of Styrene-Butyl Methacrylate Copolymers by High Performance Liquid Chromatography

Abstract Styrene/n-butyl methacrylate (S/nBMA) and styrene/t-butyl methacrylate (S/tBMA) copolymers were separated by chemical composition using HPLC. In the case of normal phase HPLC using acrylamide gel or acrylonitrile gel as a stationary phase, S/nBMA and S/tBMA copolymers were separated by chemical composition. S/BMA copolymers were eluted from higher styrene content using dichloromethane/n-hexane as an eluent, while with the opposite elution order with tetrahydrofuran/iso-octane eluent. The difference of the elution order is explained by hydrogen bondings between the gel and the sample or eluent. In reversed phase HPLC using a styrene column and nonpolar eluent such as dichloromethane/acetonitrile, S/BMA copolymers were eluted from lower styrene content using any kind of eluent examined. On the other hand, an octadecyl methacrylate column provided no separation based on the composition. The separation using the styrene column was ascribed to the specific interaction of the phenyl groups in the sampl...

Quantitative structure-retention relationships for secondary interactions in cation-exchange liquid chromatography

Eighty-three aryl alkyl amines with a range of substituents in the aromatic ring were chromatographed on a silica stationary phase in the ion-exchange mode using a non-polar eluent which promotes hydrogen bonding interactions. The increase in retention due to the presence of the polar substituents was quantified using the functional group contribution value τ. The correlation between τ and a range of substituent physical and quantum chemical parameters was investigated using multiple regression. The increase in retention could be attributed to a hydrogen bonding interaction between the polar substituents and unionised silanols. This could be quantified in terms of the hydrogen bonding acceptor properties of the substituent (log K β) and it size, although the quality of the correlations was poor. A superior correlation was obtained using the lipophilicity (π) of the substituent. The correlations, which gave an R 2 of 0.8423 at best were unsuited to accurate retention prediction.

Separation of styrene‐methacrylate copolymers by composition using normal and reversed‐phase high‐performance liquid chromatography

AbstractThe separation of styrene‐methacrylate copolymers by chemical composition was studied using high‐performance liquid chromatography (HPLC). With the combination of acrylonitrile (polar) gel and nonpolar eluent or of styrene (nonpolar) gel and polar eluent, poly(styrene‐co‐methylmethacrylate) was separated by the adsorption mechanism. The former is designated as normal and the latter as reversed phase. With other combinations, the copolymer was separated mainly by fractional dissolution mechanism. The sample eluted slightly earlier as molecular weight decreased. The molecular weight effect on the reversed‐phase HPLC was smaller than that on the normal phase. A gel with an exclusion limit of 3 × 103 exhibited greater molecular weight dependence and worse resolution than a gel with an exclusion limit of 50 × 104.Poly(styrene‐co‐n‐butyl methacrylate) also was separated on the basis of chemical composition by normal and reverse‐phase HPLC. However, poly(styrene‐co‐t‐butyl methacrylate) was separated only by reverse‐phase HPLC. When octadecyl methacrylate gel was used instead of styrene gel in reverse‐phase HPLC, a good separation was not obtained. This indicates a specific interaction between the phenyl group of the styrene gel and the sample.

Quantitative structure-type analysis of heterocompound—hydrocarbon mixtures : VI. Characterization of the nature of neutral heterocompounds in a product of brown coal refining

Neutral heterocompounds are one of the major fractions of the pyrolysis or hydrogenation products of brown coals. They are classified into two groups by chromatographic methods. The first group (thiophenes, aliphatic ketones) elutes from the normal phase with non-polar eluents, in analogy with aromatic hydrocarbons. They can be separated from aromatic hydrocarbons by complex formation with palladium chloride [ Fuel, 65 (1986) 270-273; J. Chromatogr., 509 (1990) 27–32]. The second group elutes from the normal phase with polar eluents. The neutral heterocompounds in an extract of heat-pretreated brown coal were separated by semipreparative high-performance liquid chromatography. They were fractionated by increasing polarity and subsequently characterized by Fourier transform infrared spectrometry, protonnuclear magnetic resonance and mass spectrometry. Results to these spectrometric methods ( i.e. the existence of hydroxy and carbonyl residues) could be verified by derivatization with 2,4-dinitrophenylhydrazine and 3,5-dinitrobenzoylchloride followed by qualification of these derivatives by reversed-phase chromatography. The neutral heterocompounds were hydrogenated in two steps, and the resulting hydrocarbons were characterized by semipreparative and analytical high-performance liquid chromatography, as well as by capillary gas chromatography. General conclusions about the structures, as result of the combination of the different applied methods, could be made.

Optical resolution of racemic compounds on chiral stationary phases of modified cellulose

Several alcohols having chiral centres on the chain linking phenyl and hydroxyl groups were chromatographed on a chiral stationary phase, based on cellulose tris-(3,5-dimethylphenylcarbamate) (Chiralcel-OD; OD-CSP). The mobile phases used were polar and non-polar solvents consisting of n-hexane and acetonitrile containing 2-propanol or benzene as modifier. The solutes containing hydroxyl groups were not eluted with non-polar eluents, and enentiomeric separation was less effective with eluents containing benzene. The enantiomeric elution order was not affected by changes in eluent polarity. The results suggest that the hydroxyl group was adsorbed on OD-CSP non-stereoselectively and that the phenyl group plays an essential part in the chiral recognition of solutes by OD-CSP. With both polar and non-polar eluents the solutes are oriented toward OD-CSP in a similar conformation.

High-Performance Liquid Chromatography Using Stereoregular Poly(methyl methacrylate)s as Stationary Phases

Poly(methyl methacrylate)s (PMMAs) with five different tacticities were prepared by radical or anionic polymerization and used as stationary phases (packing materials) for high-performance liquid chromatography (HPLC). From retention times of small molecules on these stationary phases, tacticity effect on interactions between PMMA and solutes was evaluated. Aromatic hydrocarbons were chromatographed by using polar eluents, and polar benzene derivatives by nonpolar eluents. The retention times on the syndiotactic PMMA phase were much longer than those on the isotactic PMMA phase. The infrared spectra of the PMMAs and HPLC data indicated that highly isotactic PMMA changes its conformation depending on the polarity of eluents. Poly(ethyl methacrylate)s and poly(benzyl methacrylate)s with different tacticities were also used as stationary phases.

Chromatographic Optical Resolution by Optically Active Poly(diphenyl-2-pyridylmethyl methacrylate) with a Highly One-Handed Helical Structure

The ability of optical resolution of (−)-poly(diphenyl-2-pyridylmethyl methacrylate) (PD2PyMA) with highly one-handed helicity was investigated by using it as a chiral stationary phase for high-performance liquid chromatography. The optically active polymer was prepared with an organolithium complex of (+)-(2S,3S)-dimethoxy-1,4-bis(1-perhydroazepinyl)-butane. When methanol was used as an eluent, PD2PyMA resolved many racemic compounds completely and several binaphthyl derivatives were better resolved than in resolution by optically active poly(triphenylmethyl methacrylate) (PTrMA). When a non-polar eluent, hexane-2-propanol mixture was used, PD2PyMA exhibited higher optical resolving power to several alcohols than PTrMA. This was ascribed to the strong interaction between the 2-pyridyl group of the PD2PyMA and the hydroxy group of the racemate in the non-polar eluent. In order to evaluate the durability of the column in methanol, the solvolysis rates of the monomer and chiral stationary phase were measured. This revealed that PD2PyMA has higher durability in methanol than PTrMA.

Thermal treatment of silica and its influence on chromatographic selectivity

It is generally accepted that the retention of solutes in non-polar eluents with silica as a stationary phase depneds on the silanol concentration. By thermall treatment silanols can be removed at temperatures above 200°C. It can be shown by Fourier transform (FT)-IR spectroscopy that the vicinal silanols are removed and that number of isolated silanols (sharp absorption at 3740 cm −) increases. The decrease of vicinal silanols can be detected chromatographically by a coresponding decrease in the retention of hydroxyl group-containing solutes. The retention of solutes with hydrogen-bonding acceptors is not affected by this removal of vicinal silanols. Their retention depends solely on the surface concentration of isolated silanols. At temperatures above 600°C the concentration of isolated silanols also decreases. Consequently, the retention of these solutes decreases only on silicas treated at higher temperature. Rehydration of silica surface is completely reversible, if the thermal treatment does not exceed 400°C. It appears that during chemical modification with chlorosilanes only the isolated hydroxy groups react.

Optimization of enantiomeric separations with chiral bonded phases

The preparation and properties of chiral bonded phases with amino acid groups are described. These phases were used in non-polar eluents and in aqueous systems in the presence of Cu2+ ions in the ligand-exchange mode. The optimization of chiral resolution is demonstrated for both cases. With non-polar eluents similarity between bonded groups and solutes is required. The elution could be accelerated by non-protonic moderators.