High Performance Centrifugal Partition Chromatography Research Articles

Separation of Some Transition Metal Ions by High Performance Centrifugal Partition Chromatography with bis‐2‐Ethylhexylphosphinic Acid

The separation of such metal ions as Fe(III), Zn(II), Cu(II), Mn(II), Co(II), and Ni(II) has been investigated by high performance centrifugal partition chromatography (HPCPC) using 0.16 M bis(2‐ethylhexyl)phosphinic acid/heptane as a stationary phase. Acetate, chloroacetate, and tartrate buffers were used as mobile phases. The above six metal ions could be well separated by HPCPC using the step elution method, in which the pH of the mobile phases was changed at fixed elution times. The Co(II) cations present in unrefined Ni(II) sulfate solution could also be separated by this HPCPC method. The sample solution was continuously delivered into the stationary phase by a pump, and the Co(II) cations were found to be preferably retained into the stationary phase. The HPCPC system was operated with 2,136 partition channels, at a rotation speed of 800 rpm, and at a flow rate of 2.0 cm3/min.

Separation of protoberberine quaternary alkaloids from a crude extract of Enantia chlorantha by centrifugal partition chromatography

High-performance centrifugal partition chromatography (HPCPC) has been successfully applied to the separation of four protoberberine quaternary alkaloids, namely palmatine, jatrorrhizine, columbamine and pseudocolumbamine, from a methanolic extract (M 1, 1.47 g) of Enantia chlorantha Oliver stem bark. For their isolation, two successive biphasic solvent systems composed of dichloromethane–methanol–water (48:16:36, v/v) were selected. The aqueous-rich phase was the stationary phase and the organic-rich phase was the mobile phase. The first system, containing potassium perchlorate, allowed to isolate 600 mg of palmatine, and to obtain 146 mg of a mixture (M 2) containing only jatrorrhizine, columbamine and pseudocolumbamine. The second biphasic system, prepared with water alkalinized with sodium hydroxide, was employed to isolate the M 2 components. This system applied to the purification of 70 mg of M 2 allowed to obtain 16 mg of jatrorrhizine and 13 mg of columbamine. To obtain pseudocolumbamine (16 mg), the elution mode was reversed, the aqueous-rich phase becoming the mobile phase, and the organic-rich phase becoming the stationary one. Analytical reversed-phase high-performance liquid chromatography, NMR, high-resolution mass spectrometry and UV spectrometry were used to verify the identity and the purity of the isolated compounds.

Separation of some metal ions by high performance centrifugal partition chromatography with di‐2‐methylnonylphosphoric acid

AbstractThe separation of such metal ions as Cu(II), Mn(II), Co(II), Ni(II), Mg(II) and Ca(II) has been investigated by high performance centrifugal partition chromatography (HPCPC) employing di‐2‐methylnonylphosphoric acid/heptane as a stationary phase. The four transition metal ions have mutually been separated by the two‐step elution method, changing the pH of the chloroacetic acid mobile phase, and the two alkaline earth metal ions have been separated by an isocratic elution. The HPCPC system was operated with 2136 partition channels, at a rotation speed of 800 rpm, and at a flow rate of 2.0 cm3 min−1. The elution curve was obtained by monitoring the absorbance of each metal complex post‐labeled with chromogenic compounds. Copyright © 2003 Society of Chemical Industry

Isolation and Purification of Kava Lactones by High Performance Centrifugal Partition Chromatography

Kava kava (Piper methysticum) is currently used in a variety of herbal and homeopathic preparations to induce relaxation, treat anxiety, or induce sleep. The pharmacologically active compounds consist of a group of structurally related lactone derivatives that are concentrated in the roots, rhizomes, and root stems. The major constituents responsible for 95% of the total pharmacological activity are desmethoxyyangonin, dihydrokavain, yangonin, kavain, dihydromethysticin, and methysticin. The concern over the possible hepatoxicity of kava has led regulatory agencies in countries such as Germany, Switzerland, France, Canada, the United Kingdom, as well as the United States to respond by warning consumers about the potential risks of kava use, or by removing kava‐containing products from the marketplace. The high demand for purified kava‐lactones has emerged to facilitate necessary testing to investigate the rising concern over these cases of liver toxicity. A separation method using high performance centrifugal partition chromatography (HPCPC) has been developed for the isolation of each kava lactone from a CO2 extract of P. methysticum in a single chromatographic run.

High performance centrifugal partition chromatographic separation of alkaline earth metal ions with bis‐2‐ethylhexylphosphinic acid

AbstractThe mutual separation of Ca(II), Mg(II), Sr(II), and Ba(II) was studied by high performance centrifugal partition chromatography using 0.16 M bis‐2‐ethylhexylphosphinic acid in heptane as a stationary phase. Two‐step elution of the four metal ions loaded was accomplished with aqueous chloroacetic acid mobile phases (pH 6.50 and 5.30). Ethanol (5%) was added to the pH 6.50 mobile phase for the separation of Sr(II) and Ba(II). The chromatographic conditions were 2,136 partition channels, 800 rpm rotational speed, and 1.5 cm3/min flow rate. The elution curve was obtained by monitoring the absorbance of each metal complex post‐labeled with a chromogenetic agent.

Separation of Calcium (II), Magnesium (II), Strontium (II), and Barium (II) by High Performance Centrifugal Partition Chromatography with Some Organophosphorus Compounds

Some kinds of organophosphorus compounds were compared for the separation of calcium (II), magnesium (II), strontium (II), and barium (II), in aqueous media by continuous high performance centrifugal partition chromatography (HPCPC). Among extractants investigated, bis‐2‐ethylhexylphosphinic acid (BEHPA) showed the most selective reagent for the extraction and separation of the four alkaline earth metal ions. Well‐defined HPCPC separation of the four metal ions, therefore, was performed by using a heptane solution of BEHPA as a stationary phase. The mobile phases used were 0.1 M chloroacetic acid solutions (pH 5.30 and 6.50) containing 5% ethanol. The HPCPC system was operated with 2136 partition channels, at a rotational speed of 800 rpm, and at a flow rate of 1.5 cm3/min.

Separation of scandium, yttrium and lanthanum in high-performance centrifugal partition chromatography with S-octyl phenyloxy acetic acid

Separation of scandium(III), yttrium(III) and lanthanum(III) was performed by high-performance centrifugal partition chromatography (HPCPC) employing the stationary phase of S-octyl phenyloxy acetic acid (CA-12). The liquid–liquid extraction behavior of CA-12 for Sc(III), Y(III) and La(III), the acidity of aqueous phase, and the operation conditions of HPCPC were examined. The retention volume (VR) increased with the order of Y(III), La(III) and Sc(III) accompanied with the elution of the mobile phase in different pH, which is lowered from 4.6 to 2.1.

High Performance Centrifugal Partition Chromatographic Separation of Cu(II), Mn(II), Co(II), and Ni(II) Using Di-2-Methylnonylphosphoric Acid

A novel and simple method has been developed for the mutual separation of such metal ions as Cu(II), Mn(II), Co(II), Ni(II) by high performance centrifugal partition chromatography (HPCPC) with di-2-methylnonylphosphoric acid/heptane as a stationary phase. The HPCPC system was operated with 2,136 partition channels, at a rotational speed of 800 rpm, and at a flow rate of 2.0 cm3/min. The four transition metal ions could be eluted separately by changing pH of the chloroacetic acid mobile phase at two steps. The elution curves were obtained by monitoring the absorbance of each metal complex post-labeled with 4-(2-pyridylazo)resorcinol.

HPCPC Separation of Proteins using Polyethylene Glycol-Potassium Phosphate Aqueous Two-Phase

ABSTRACT High Performance Centrifugal Partition Chromatography (HPCPC) is a practical and suitable method, particularly on the preparative scale, for the separation of biomolecules such as proteins, enzymes, etc. Aqueous two-phase system is also very attractive for the isolation of biomolecules. Aqueous polymer phase system composed of polyethylene glycol 6000-potassium phosphate has been used for the countercurrent chromatographic separation of bovine serum albumin (BSA) and lysozyme using HPCPC. The separation of BSA and lysozyme under various conditions such as various flow rates, rotational speeds, pH of the solvent, and the retention of stationary phase has been studied in the present investigation. The baseline separation of BSA and lysozyme has been also observed. The results of this study demonstrate that HPCPC is useful for separation of proteins with aqueous two-phase systems.

SEPARATION OF DITERPENOID ALKALOIDS BY HIGH PERFORMANCE CENTRIFUGAL PARTITION CHROMATOGRAPHY

Complex diterpenoid alkaloids of close Rfvalues have been separated by High Performance Centrifugal Partition Chromatography (HPCPC). Model LLB-M (Series 1000) by Sanki Laboratories Inc. was used for these separations. Especially highly polar (on Al2O3) alkaloids which could not be isolated by conventional methods using a solid support, owing to irreversible retention, could be isolated easily as this separation method can be used in the reverse phase mode by careful selection of the biphasic solvent system. The HPCPC instrument was found easy to handle, dependable, applicable to the entire range of polarity of diterpenoid alkaloids, and gave reproducible results. When some of the fractions furnished a mixture of minor alkaloids, the mixture was resolved by a quick separation technique such as separation on a Chromatotron and preparative TLC. In all, eight different mixtures of known as well as crude alkaloidal mixtures were separated and the results are reported here. Isolated pure known compounds were identified through their spectroscopic (IR., 1H, 13C, DEPT NMR) and physical data, as well as comparison of their TLC behavior with that of authentic samples. A new diterpenoid alkaloid, 13-acetylvakhmatine (20), was also isolated in one of the separations.

What's new in chromatography

A column designed to eliminate the problem of charge interaction and a preparative/analytical high-performance centrifugal partition chromatography system — highlights of this week's chromatography/HPLC feature.