Reversed-phase High-performance Liquid Chromatographic Behaviour Research Articles

Structure–retention and mobile phase–retention relationships for reversed-phase high-performance liquid chromatography of several hydroxythioxanthone derivatives in binary acetonitrile–water mixtures

The reversed-phase high-performance liquid chromatographic (RP-HPLC) behavior of some newly synthesized hydroxythioxanthone derivatives using binary acetonitrile–water mixtures as mobile phase has been examined. First, the variation in the retention time of each molecule as a function of mobile phase properties was studied by Kamlet–Taft solvatochromic equations. Then, the influences of molecular structure of the hydroxythioxanthone derivatives on their retention time in various mobile phase mixtures were investigated by quantitative structure–property relationship (QSPR) analysis. Finally, a unified model containing both the molecular structure parameters and mobile phase properties was developed to describe the chromatographic behavior of the systems studied. Among the solvent properties, polarity/polarizability parameter ( π *) and hydrogen-bond basicity ( β), and among the solute properties, the most positive local charge (MPC), the sum of positive charges on hydrogen atoms contributing in hydrogen bonding (SPCH) and lipophilicity index (log P) were identified as controlling factors in the RP-HPLC behavior of hydroxythioxanthone derivatives in actonitrile–water binary solvents.

Normal-phase and reversed-phase high-performance liquid chromatographic behaviour and particle beam mass spectrometric characterization of alkyne-substituted iron–carbonyl clusters

The chromatographic behaviour of seven iron–carbonyl compounds substituted with alkynes R 2C 2 was studied both in normal-phase and reversed-phase chromatography. Several kinds of stationary phases were considered, including silica, CN, C 18 and phenyl columns. Positive-ion and negative-ion chemical ionization mass spectra of the compounds obtained with a particle beam MS system in flow injection analysis are reported. LC–MS experiments were performed for confirmation purposes and in order to check the integrity of the analytes after the LC separation.

Reversed-Phase High-Performance Liquid-Chromatographic Behavior of Phthalic Acid and Terephthalic Acid in the pH Region around the Second pKa Values

Abstract In a reversed-phase high-performance liquid-chromatographic analysis phthalic acid and terephthalic acid were observed as two clearly separated peaks with a mobile phase of pHs around the second pKa values involving the monoanion and dianion species.

Reversed-phase high-performance liquid chromatographic behaviour of some metal 1-(2-pyridylazo)-2-naphthol chelates

The HPLC behaviour of Cu(II), Co(III), Ni(II) and FE(II) chelates with 1-(2-pyridylazo)-2-naphthol (PAN) on alkyl-bonded silica gel stationary phase was studied in detail. Peaks of [Ni II(PAN) 2] and [Fe II(PAN) 2] were observed with the mobile phase acetonitrile-water (70:30, v/v). The cationic chelates, [Cu II(PAN)] + and [CoIII(PAN) 2] +, were found to be adsorbed on the stationary phase as a result of interaction with the residual silanol groups. A sharp peak of [Co III(PAN) 2] + chelate was obtained by adding one of several organic or inorganic salts to the mobile phase, but a [Cu II(PAN)] + chelate peak could only be obtained on addition of ammonium thiocyanate. The retention of the CO(III) chelate depended to a large extent on the alkyl chain length of the stationary phase and the species of an organic modifier in the mobile phase.

Effect of differing thiols on the reversed-phase high-performance liquid chromatographic behaviour of o-phthaldialdehyde-thiol-amino acids

Comparaison des effets de plusieurs homologues soufres et de deux derives Kriolo ionisables sur les temps de retention de l'acide aspartique, la serine, l'arginine et la lombricine

Reversed-phase high-performance liquid chromatographic behavior of peptide isomers including a D-amino acid

The chromatographic behavior of ten peptide isomers was investigated using isocratic eluting with reversedphase high-performance liquid chromatography. These peptides are growth hormone releasing factor, consisting of 29 amino acid residues and its isomers where on amino acid residue in the sequence was replaced with the corresponding D-amino acid. Linear relationship was observed between the logarithm of the capacity factors of the isomers and the acetonitrile concentration in the mobile phase with correlation coefficients of 0.995–0.998. The regression coefficients were almost the same for all the isomers with a relative standard deviation of 5.3%. These results suggest that the chromatographic behavior of peptide isomers is also predictable from the solvophobic theory. The regression coefficient reflects the molecular weight and the Y-intercept represents the hydrophobicity of the isomer. The peptide isomers can be separated from one another, based on the differences in the hydrophobicity of each isomer.

Effect of mass loadability, protein concentration and n-alkyl chain length on the reversed-phase high-performance liquid chromatographic behaviour of bovine serum albumin and bovine follicular fluid inhibin

The chromatographic behaviour of bovine serum albumin and partially purified preparations of the 58 kilodalton form of bovine follicular fluid inhibin has been investigated using two different n-alkylsilica stationary phases. In particular the effects of mass loadability, protein concentration and loading conditions on the relative retention, peak width and recovery of these proteins have been studied over a dynamic range up to 100 mg protein per g packing material per injection. The influence of variable amounts of more abundant contaminating proteins such as bovine serum albumin in crude inhibin preparations on the chromatographic purification of trace quantities of the 58 kildalton inhibin protein has also been examined. Based on these observations, recommendations are offered for teh selection of protein loading conditions with n-alkylsilica stationary phases, particularly for the trace recovery and purification of hydrophobic proteins similar to inhibin where self-aggregation, adsorption to glass or plastic surfaces, and aberrant chromatographic behaviour on size exclusion or adsorptive chromatographic supports may occur.