High-performance Liquid Chromatographic Behaviour Research Articles

Multielement analysis by high-performance liquid chromatography following solvent extraction with acetylacetone

The high-performance liquid chromatographic behavior of acetylacetone (AA) metal chelates was investigated with silica gel, C/sub 18/, C/sub 8/, and phenyl (Ph) columns. AA chelates of Cu, Be, Al, Ga, Pd, and Fe have been separated by Cosmosil 5 C/sub 18/, 5 C/sub 8/, and 5 Ph columns, while Cu, Pd, and Fe chelates were separated by Cosmosil 5 SL (silica gel) and LiChrosorb RP-18, RP-8, and Si 60 columns. log-log calibration curves for Cu, Fe, and Pd were made with the above seven columns after solvent extraction of the metals at pH 5 from 50-mL aqueous solutions into dichloromethane as AA chelates. The best calibration curves were obtained by use of the Cosmosil 5 C/sub 1/(. The linear concentration range of each metal by the Cosmosil 5 C/sub 18/ column was 10 ng/mL (ppb) to 20 ..mu..g/mL (ppm) for Cu, 5 ppb to 10 ppm for Fe, and 5 ppb to 10 ppm for Pd with a correlation coefficient of more than 0.9995. The presented method has been applied to the determination of Cu and Fe in water.

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

Effect of hydrogen bonding on the high-performance liquid chromatographic behaviour of organic compounds : Relationship between capacity factors and partition coefficients

Capacity factors ( k′) of various compounds were determined by high-performance liquid chromatography on ODS (octadecylsilica) and gly-CPG (glyceryl-coated controlled-pore glass) with a mobile phase consisting of various proportions of methanol and water, and the correlation of the k′ values with the P oct values (partition coefficients between octanol and water) of these compounds was examined. On both columns, log k′ increased with increase in log P oct. However, introduction of a hydrogen bonding term was necessary to obtain a single correlation between log k′ and log P oct for a wide variety of compounds. On both columns, the effect of hydrogen bonding on k′ became smaller with a decrease in the proportion of methanol in the mobile phase, but in different manners on the two columns: among compounds with the same log P oct values, those with the ability to form hydrogen bonds had less affinity than those with no ability to form hydrogen bonds on ODS, and vice versa on gly-CPG.

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.

Organotitanium chemistry: VII. Study on HPLC of bis- and mono-(substituted cyclopentadienyl)titanium derivatives

The high-performance liquid chromatographic behavior of 56 bis- and mono-(substituted cyclopentadienyl)titanium dichlorides was investigated. According to their capacity factors ( K′) and separation efficiencies ( N), the relationship between chromatographic behavior and structure of titanium complexes was discussed.

Reversed-phase high-performance liquid chromatographic retention behaviour of benzylpenicillin and its acid-base degradation products.

The determination of benzylpenicillin and its acid-base degradation products by ion-suppression, ion-pair and buffered reversed-phase HPLC separation modes are compared. The latter technique is the preferred method of determination. The effects on sample capacity of pH, buffer concentration, temperature and organic modifier type and content are discussed. Studies were performed on Spherisorb S5 ODS and S5 ODS2 HPLC columns utilising isocratic elution with UV detection. The similarity of retention behaviour in buffered reversed-phase and ion-pair reversed-phase HPLC is briefly discussed.

Modification of the high-performance liquid chromatographic retention behaviour of 2-aminophenol by the inclusion of metal ions in the mobile phase

Modification of the high-performance liquid chromatographic retention behaviour of 2-aminophenol by the inclusion of metal ions in the mobile phase

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.

Stationary phases : XV. High-performance liquid chromatographic behaviour of quinones on a safrole stationary phase

Stationary phases : XV. High-performance liquid chromatographic behaviour of quinones on a safrole stationary phase

Reaction products of sulbactam with pyrazole, 1,2,4-triazole and imidazole: High-performance liquid chromatographic behavior and structural investigation.

The reactions of sulbactam (I) with pyrazole, 1, 2, 4-triazole and imidazole in weakly alkaline solutions yielded 1-(5-carboxy-6-methyl-6-sulfino-4-aza-2-heptenoyl)-pyrazole (III), -1, 2, 4-triazole (IV), and -imidazole (V), respectively. The proton nuclear magnetic resonance spectra and high-performance liquid chromatographic (HPLC) behavior indicate that III, IV and V each exist as a mixture of E- and Z-isomers in a ratio of about 2 : 1 in aqueous solutions at low temperature, and that rapid interconversion between the E- and Z-isomers occurs at high temperature. Compounds III, IV and V were converted to methyl 5-carboxy-6-methyl-6-sulfino-4-aza-2-heptenoate (II) in methanol.

High-performance liquid chromatographic elution behaviour of oligosaccharides, monosaccharides and sugar degradation products on series-connected ion-exchange resin columns using water as the mobile phase

The high-performance liquid chromatographic separation of oligosaccharides, monosaccharides, sugar degradation products and alcohols using a series-connected system of different ion-exchange columns with water as the eluent was investigated. The non-additivity of the number of theoretical plates ( N), the height equivalent to a theoretical plate ( H) and the resolution ( R S) on ion-exchange phases is discussed.

Effect of column temperature on high-performance liquid chromatographic behaviour of inorganic polyphosphates: II. Gradient ion-exchange chromatography

The column temperature as well as a chloride concentration gradient were found to be effective for the optimization of the analysis of inorganic polyphosphates in gradient ion-exchange chromatography. The effects of column temperature on both retention time and band width are discussed. A computer-assisted retention prediction system was successfully applied to the optimization of the gradient elution conditions. More than 35 kinds of polyphosphates could be separated completely under the optimum conditions.

High-performance liquid chromatographic behaviour of some pharmaceutically important thiazide, loop and potassium-sparing diuretics

This paper deals with the specific identification of several thiazide, potassium-sparing and loop diuretics. The liquid chromatographic behaviour of these compounds is studied. Different organic modifiers (methanol, acetonitrile and tetrahydrofuran) are compared in terms of selectivity for the thiazide diuretics. An acetonitrile—water (40:60) eluent can be used to identify the thiazide diuretics. The loop and potassium-sparing diuretics are well chromatographed at an acidic pH in the presence of propylamine hydrochloride. This study enables us to select the right mobile phase composition for any given selectivity or resolution. The determination of the dead volume in different chromatographic systems is also discussed. A mixture of organic solvent and deuterium oxide in the same volume ratio as the eluent is used as dead volume marker. The signal is monitored with a UV detector at low wavelength.

Effect of column temperature on high-performance liquid chromatographic behaviour of inorganic polyphosphates : I. Isocratic ion-exchange chromatography

The isocratic elution conditions, column temperature and eluent concentration, at pH 10 for the analysis of inorganic polyphosphates were optimized to minize analysis time and to maximize resolution. The retention time was described as a function of eluent concentration. The column temperature affected drastically both the retention time and the band broadening of polyphosphates. The enthalpy change associated with the retention was calculated to be positive. A computer-assisted retention prediction system based on these relationships was successfully applied to the optimization of the elution conditions. The graphical presentation of the optimal elution conditions provided a simple technique for obtaining an adequate set data on the column temperature and eluent concentration for the complete separation and rapid analysis of inorganic polyphosphates.

General Approach for the Estimation of Octanol/Water Partition Coefficient by Reversed-Phase High-Performance Liquid Chromatography

Abstract General approach for the relation of reversed-phase high-performance liquid chromatographic retention behaviour to the hydrophobic properties of drugs was developed. Hydrophobicity of compounds was characterized by the logarithm of 1-octanol/water partition coefficient (log Po/w). Reversed-phase retention times of 26 model compounds (log Po/w values of them ranged from −1.22 to 3.84) were measured using 3 to 5 different mixture of acetonitrile and water as eluent and the logarithm of the capacity ratios (log k′) was calculated. The linear relationship between the log k′ values and the percentage of the acetonitrile in the eluent was tested for each molecule. The slope and the intercept (log k′o) of these straight lines were calculated and introduced to the following regression equation: a, b and c, were constants obtained by least squares method. Correlation coefficient of the equation was 0.95. The quotient of the values of a and b gave the percentage of the acetonitrile in the eluent (48%) by w...

High-performance liquid chromatographic elution behaviour of alcohols, aldehydes, ketones, organic acids and carbohydrates on a strong cation-exchange stationary phase

The high-performance liquid chromatographic separation of alcohols, aldehydes, ketones, carboxylic acids and carbohydrates on a polystyrene-based strong cation-exchange resin is described. The column temperature was found to be a very important parameter for optimizing separations of these substances. The effect of different functional groups on the elution behaviour is discussed.

High-performance liquid chromatography of homologous titanaindene complexes

The high-performance liquid chromatographic (HPLC) behavior of homologous titanaindene complexes has been investigated. Various polar (silica, cyano-bonded, phenyl-bonded) and non-polar (C 18-bonded) adsorbents were employed in this study for normal-phase and reversed-phase HPLC, respectively. Data reported include capacity factors ( k′), separation efficiencies ( N), tailing factors ( T) and compound resolutions ( R). Normal-phase separation of a titanaindene structural isomer pair on a phenyl-bonded silica column is demonstrated.

High-performance liquid chromatographic studies on n-alkylphtalimides : II. A method for calculating capacity factors for members of a homologous series at different mobile phase compositions

The high-performance liquid chromatographic behaviour of non-branched N-alkylphthalimides on LiChrosorb RP-8 was studied as a function of the alkyl carbon number and the methanol—water ratio. The linear dependence of log k′ on alkyl carbon number and log k′ on log c methanol have been used as a basis for deriving a general formula for calculating the capacity factor for any member of the homologous series at any methanol—water mobile phase composition. A good agreement was observed between the measured and the recalculated data.

High-performance liquid chromatographic behaviour of N-substituted phthalimides : Calculation of capacity factors for members of the homologous series

The high-performance liquid chromatographic behaviour of some N-substituted phthalimides on normal and reversed-phase columns was studied. The retention of the compounds is discussed in terms of shielding of the polar CONCO group of phthalimide by non-polar or slightly polar substituents. The linear dependence of log k′ on the number of carbon atoms of the alkyl substituent of N-alkylphthalimides has been used as a basis for deriving a general formula for calculating the capacity factor for any member in the homologous series.

High-performance liquid chromatographic behaviour of phytoactive derivatives of diazines

High-performance liquid chromatographic behaviour of phytoactive derivatives of diazines