Semi-preparative Reversed-phase High-performance Liquid Chromatography Research Articles

Optimization of the separation of technical aldicarb by semi-preparative reversed-phase high-performance liquid chromatography

A computer-assisted method is presented for optimization of separation of technical aldicarb pesticide by semi-preparative reversed-phase HPLC. The optimization of the expected separation is based on a polynomial estimation from five preliminary experiments. A statistical scanning technique was used for optimization and the designated resolution was established for chromatographic performance measurement in this method. Excellent agreement was obtained between the predicted and experimental results.

Separation and identification of phytoalexins from leaves of groundnut ( Arachis hypogaea) and development of a method for their determination by reversed-phase high-performance liquid chromatography

Leaves of groundnut, Arachis hypogaea, infected with the early leaf spot fungus, Cercospora arachidicola, were extracted in aqueous ethanol and the phytoalexins partitioned into ethyl acetate. Flash chromatography of the ethyl acetate extract on silica gel yielded fractions with one to five compounds from which the phytoalexins could be isolated by semipreparative reversed-phase high-performance liquid chromatography (HPLC). The major phytoalexins were demethylmedicarpin, formononetin, 7,4′-dimethoxy-2′-hydroxyisoflavanone and medicarpin. Minor components were 7,2′-dihydroxy-4′-methoxyisoflavanone and daidzein. Compounds were identified by cochromatography and comparison of their ultraviolet and mass spectra with authentic samples using an HPLC system equipped with a diode-array detector, HPLC mass spectrometry and gas chromatography—mass spectrometry of their trimethylsilyl derivatives. A solid-phase extraction method was developed for processing large numbers of samples. Acetonitrile eluates from C 18 cartridges were separated by reversed-phase HPLC and the phytoalexins quantified by reference to external standards of the authentic compounds.

Isolation from fetal bovine serum of a peptide similar to the alpha chain of thrombin by reversed-phase high-performance liquid chromatography

During the preparation of erythrotropin from fetal bovine serum, a group of peptides co-eluted with this erythroid cell stimulating factor on semi-preparative reversed-phase high-performance liquid chromatography. They could be subsequently separated by a combination of reversed-phase high-performance liquid chromatography in the presence of heptafluorobutyric acid as ion-pairing reagent and gel permeation high-performance liquid chromatography. One of these peptides has been extensively purified. Partial amino acid sequence analysis indicated that fourteen of the seventeen N-terminal amino acids are identical with the N-terminal sequence of the alpha chain of bovine thrombin. The same isolation procedure could be useful for the identification of other major peptides of fetal bovine serum.

Removal of counter-ion reagent after semi-preparative reversed-phase ion-pair high-performance liquid chromatography

Removal of counter-ion reagent after semi-preparative reversed-phase ion-pair high-performance liquid chromatography

Separation and Assignment of the Tryptic Peptides of Human Growth Hormone (hGH) and the 20K Dalton hGH Variant by Reversed Phase High Performance Liquid Chromatography

Abstract Reversed-phase high performance liquid chromatography (RP-HPLC) has been used to separate the peptides generated by tryptic cleavage of human growth hormone (hGH) and the 20K dalton human growth hormone variant. The total amino acid compositions of both these pituitary proteins has been accounted for on the basis of these chromatographic mapping procedures. Structural analyses of the peptides isolated from semi-preparative RP-HPLC separations has confirmed that the primary structure of the variant differs from that of the sequence of hGH by deletion of the amino acid residues 32–46.

Isolation and purification of Amadori compounds by semi-preparative reversed-phase high-performance liquid chromatography

Isolation and purification of Amadori compounds by semi-preparative reversed-phase high-performance liquid chromatography