Separation of pyrimidine derivatives by reversed-phase high-performance liquid chromatography

Chromatographic behavior and separation conditions of pyrimidine derivatives were studied by high-performance liquid chromatography using a reversed-phase column and a multiwave UV detector.     

Separation of cytochromes c by reversed-phase high-performance liquid chromatography

Six kinds of cytochrome c of different origin, i.e., bovine, chicken, dog, horse, rabbit and tuna, were subjected to separation by reversed-phase high-performance liquid chromatography on three commercial packing materials; octadecyl-, octyl- and cyanoalkyl-silicas. The effects of reversed-phase material, mobile phase and temperature on the separation of cytochromes c were examined. The parameters of the mobile phase were the organic modifier, the pH, the salt concentration and additives. Under optimal conditions, five of the six cytochromes c were resolved in 10 min. The relative retention values cannot be explained in terms of the relative lipophilicities of the side-chains of the amino acid residues.     

Separation of polypeptide antibiotics by reversed-phase high-performance liquid chromatography

Summary The influence of different reversed-phase packings and the addition of acidic modifiers to the mobile phase was observed on the separation of basic and neutral polypeptide antibiotics by gradient elution. A dependence of pore size, coverage, reaction type and endcapping of the packings was not observed. Nevertheless, not all reversed-phase packings were suitable for the separation of polypeptides, especially of basic molecules. The addition of phosphoric or perchloric acid to the mobile phase prevented adsorption of the basic polypeptide antibiotics on the stationary phase.     

Separation of tubulin subunits by reversed-phase high-performance liquid chromatography

When properly solubilized with trifluoroacetic acid (TFA), alpha- and beta-tubulin subunits from a variety of sources may be resolved at high yield by reversed-phase high-performance liquid chromatography (HPLC), using a Waters muBondapak C18 column and simple linear aqueous acetonitrile gradients containing TFA. The tubulin subunits are typically the most non-polar proteins present, with the beta-tubulin subunit eluting before the alpha. Column temperature above ambient improve both the resolution and the yield; less polar solvent systems do not. Tubulins not freely soluble in aqueous TFA may be solubilized in 6 M guanidine-hydrochloric acid with no change in retention time. Other columns with shorter carbon chain lengths and larger pore size produce a single, unresolved tubulin peak. Reversed-phase HPLC analysis provides an independent comparative evaluation of organelle-specific tubulins, with characteristic retention time differences observed between homologous ciliary and flagellar outer doublet tubulin subunits and also between them and their cytoplasmic counterparts.     

Separation of retinyl esters by non-aqueous reversed-phase high-performance liquid chromatography

Rapid separation and sensitive quantitation of vitamin A esters can be achieved by use of an acetonitrile-dichloromethane (80:20) mobile phase with a 5-microns C18 column (15 cm X 4.6 mm) and absorbance detection at 325 nm. Either a Waters Resolve or a Rainin Microsorb column was used satisfactorily. Retinyl palmitate is eluted at about 7 min (capacity factor, k' = 5.5) at a flow-rate of 1.5 ml/min; retinyl palmitate and retinyl oleate, which are usually difficult to separate, are well resolved (resolution 1.2). Sensitivity (at a signal-to-noise ratio of 10:1) is 8 pmol retinyl palmitate (equivalent to 2.5 ng retinol). Quantitation of total retinyl esters is identical to that determined by a gradient high-performance liquid chromatographic technique over the range 30-1000 ng retinyl esters. Retinyl ester peaks in rat liver extracts were identified by their characteristic light absorption spectra, susceptibility to saponification, and by co-chromatography with authentic standards. Nine vitamin A ester peaks were identified and quantitated in rat liver extracts. A 10-microns Whatman Partisil 10/25 ODS-2 column was used with the same mobile phase to obtain partial resolution of retinyl esters (resolution 1.05 between retinyl oleate and retinyl palmitate; k' = 11.0 for retinyl palmitate) and improved retention for retinol (k' = 2.5, compared with k' = 0.6 for retinol on the 5-microns column).     

Separation of pantothenic acid derivatives by reversed-phase high-performance liquid chromatography

A variant of the use of reversed-phase high-performance liquid chromatography is described which permits the separation of pantothenic acid derivatives. The stationary phase used was a μBondapak-C₁₈ (4.1 × 250 mm column; 4.6 × 50 nm precolumn). Elution was performed in the isocratic regime using as mobile phase 20 M potassium phosphate buffer (pH 5.0)-methanol (91.5:8.5). The rate of elution was 1 ml/min. Retention times in the column for phosphopantothenate, pantothenate, phosphopantetheine, CoA, and dephosphoCoA were about 3.5, 6, 10.5, 16, and 42 min, respectively. This method, with radioactive detection, can be used for the analysis of pantothenic acid derivatives in liver extracts. One hour after white rats had been injected with [¹⁴C]pantothenic acid, the abovementioned components (with the exception of dephosphoCoA) contained the label in a ratio of 4:18:54:24. Institute of Biochemistry, Academy of Sciences of the Belorussian SSR, Grodno. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 855–858, November–December, 1988.     

Separation of pantothenic acid derivatives by reversed-phase high-performance liquid chromatography

A variant of the use of reversed-phase high-performance liquid chromatography is described which permits the separation of pantothenic acid derivatives. The stationary phase used was a Bondapak-C₁₈ (4.1 × 250 mm column; 4.6 × 50 nm precolumn). Elution was performed in the isocratic regime using as mobile phase 20 M potassium phosphate buffer (pH 5.0)-methanol (91.5:8.5). The rate of elution was 1 ml/min. Retention times in the column for phosphopantothenate, pantothenate, phosphopantetheine, CoA, and dephosphoCoA were about 3.5, 6, 10.5, 16, and 42 min, respectively. This method, with radioactive detection, can be used for the analysis of pantothenic acid derivatives in liver extracts. One hour after white rats had been injected with [¹⁴C]pantothenic acid, the abovementioned components (with the exception of dephosphoCoA) contained the label in a ratio of 4:18:54:24.Institute of Biochemistry, Academy of Sciences of the Belorussian SSR, Grodno. Translated from Khimiya Prirodynkh Soedinenii, No. 6, pp. 855–858, November–December, 1988.     

Separation of guinea-pig pancreatic juice proteins by reversed-phase high-performance liquid chromatography

Using a Protesil 300 octyl reversed-phase column with a multistage water-acetonitrile solvent gradient system, it was possible to obtain a well-resolved separation of the nine major proteins present in guinea-pig pancreatic juice. The protein present in each peak of the pancreatic juice chromatogram could only be identified by molecular weight analysis as the acetonitrile denaturated the enzymes and altered their isoelectric points. However, using sodium dodecyl sulphate gel electrophoresis the protein fractions obtained by high-performance liquid chromatography were characterised. Preliminary work has indicated that this system may be capable of separating other complex biological protein mixtures, i.e., saliva.     

Separation of translationally active mRNAs by reversed-phase ion-pair high-performance liquid chromatography

An ion-pair high-performance liquid chromatographic method on C4 columns was developed for the separation of mRNAs. The addition of methylmercuric hydroxide markedly influenced the separation according to length of these molecules. A method is given to recover minute amounts of translatable mRNA from the organic phase. The resolution of mRNAs improved with increasing pore size of the column support.     

Separation of normal and abnormal hemoglobin chains by reversed-phase high-performance liquid chromatography

A review is presented of the elution patterns on reversed-phase columns of the normal and abnormal globin chains of different hemoglobin types, including 16 beta-chain variants, 7 alpha-chain variants, 9 gamma-chain variants, and 4 variants with fusion or hybrid chains. Separations appear to be based primarily on differences in hydrophobicity. The method is ideally suited for the detection of abnormal globin chains, their quantitation and their isolation. Semi-quantitative data based on the calculation of the delta/non-alpha ratios allow the detection of beta-thalassemic conditions in situations where the quantitation of hemoglobin A2 by other procedures is impossible or complicated.     

Separation and quantitation of urinary trypsin inhibitors by reversed-phase high-performance liquid chromatography

Summary Human urines contain a family of trypsin inhibitors (UTIs) in small quantities, which seem to be involved in important biological processes. A procedure for separation and quantitative determination of such endogenous inhibitors in human urine has been developed. The urine sample is adjusted to pH 8.3 and percolated through a trypsin-Sepharose 4B column: the inhibitors are eluted with acid solution. The eluate (1000 l) is analysed by RP-HPLC with programmed elution and ultraviolet detection (200 nm). Three principal peaks have been evidenced: they are due to the elution of urinary trypsin inhibitors (UTIs) having apparent m.w. of ca. 6000, 72000, 18000 daltons, respectively. Characteristics of the procedure are: limited sample volume (ca. 200 ml) and recovery of the global inhibition activity (95%). For each UTI determination reproducibility and linearity ranges are reported.

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Trennung und Bestimmung von Trypsin-Inhibitoren im Harn durch Umkehrphasen-HPLC

     

Separation of nucleotides by reversed-phase high-performance liquid chromatography: Advantages and limitations

Summary The determination of nucleotides by reversedphase high-performance liquid chromatography with 0.1 M (NH₄)₃PO₄ as an elution buffer is described. Effects of pH, type of RP packing and column efficiency are discussed. Currently used columns with efficiencies corresponding to 7,000–15,000 theoretical plates, containing 15–20% of bound carbon, have been shown not to be sufficient for the separation of nucleotides from tissue samples in the ionsuppression mode, but they provide excellent separation of 2-, 3-, and 5-monophosphates, deoxytriphosphates or synthetic derivatives of adenosine and guanosine.

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Trennung von Nucleotiden mit der RP-Hochleistungsflüssigkeits-Chromatographie: Vorteile und Beschränkungen

Zusammenfassung Die Bestimmung von Nucleotiden mit reversed-phase HPLC mit 0,1 M (NH₄)₃PO₄ als Elutionspuffer wird beschrieben. Der Einfluß des pH sowie der Art der RP-Belegung wird diskutiert, Säulen mit einer theroretischen Bodenzahl von 7000–15000, die 15–20% gebundenen Kohlenstoff enthalten, erwiesen sich als nicht geeignet für die Trennung von Nucleotiden aus Gewebeproben mittels Ionen-Verdrängung. Sie ergeben aber eine ausgezeichnete Trennung von 2-, 3- und 5-Monophosphaten, Desoxytriphosphaten oder synthetischen Derivaten von Adenosin und Guanosin.

     

Separation and quantitation of fatty acids by high-performance liquid chromatography

To facilitate the determination of the fatty acid composition of tissues and the investigation of fatty acid metabolism, we developed a method for the rapid separation by high-performance liquid chromatography and quantitation (by ultraviolet light absorption) of p-bromophenyl esters of fatty acids which vary in chain length from 10 to 22 carbon atoms. The utility of the method was demonstrated by evaluating the fatty acid composition of human uterine decidua vera tissue and human endometrial stromal cells that are maintained in monolayer culture.     

Separation of tryptic phosphopeptides of ribosomal origin by reversed-phase high-performance liquid chromatography

Phosphorylation sites for cyclic AMP-dependent kinase in ribosomal proteins and their synthetic analogues were converted to tryptic phosphopeptides and analysed by reversed-phase high-performance liquid chromatography (RP-HPLC) using gradients of acetonitrile in water and 0.1% trifluoroacetic acid. Tryptic variants differing by only NH2-terminal basic amino acid residues or phosphoryl groups were not always well resolved under these conditions. The different phospho forms could be resolved by RP-HPLC in phosphate buffers at pH 7.0. A combination of gel permeation chromatography, RP-HPLC and thin-layer cellulose mapping was found to be the most effective strategy for the absolute purification of tryptic phosphopeptides from crude tryptic digests.