Analysis of Hydroxybenzoic Acids by High Pressure Liquid Chromatography

Abstract

Good separation of a range of hydroxybenzoic acids was achieved by HPLC on a μBondapak phenyl column using 5% v/v acetic acid in water as the eluting solvent.     

The Use of High Pressure Liquid Chromatography for the Identification and Preparation of Pigments Concerned in Photosynthesis

Abstract

The chlorophylls and carotenoids present in preparations from chloroplasts of marine algae can be extracted and separated by high pressure liquid chromatography (H.P.L.C.). The reverse-phase columns; Partisil 10 ODS (Whatman), μ Bondapak C18 and μ Bondapak CN (Waters Associates) gave good separation of the different pigments. Addition of the ion-pairing agent tetrabutylamnonium phosphate to the methanol/water solvents gave improved separations with complex mixtures and identification was facilitated by examination of the column eluant at 440nm where a ll the pigments absorbed and at 650nm where only chlorophylls absorbed. The method allowed the isolation of individual pigments for further study.     

Carbohydrate Analysis by High Pressure Liquid Chromatography Using Water as the Eluent

Abstract

A μ-Bondapak C-18 column separates, by reverse phase process, mono, di and oligosaccharides within 40 min when water is used as eluent. The fractionation capabilities of this column are a function of experimental conditions (temperature and flow-rate). Chromatograms showing separations obtained for different carbohydrate mixtures are presented and discussed in terms of solubility parameters.     

On Line Detection of Plasma Borne Vasoconstrictor by the Use of High Pressure Liquid Chromatography

Abstract

An on line detection system for a plasma borne vasoconstrictor was developed using a rat heart bioassay and a reversed-phase high pressure liquid chromatograph (HPLC). Partially purified plasma borne vasoconstrictor, which is yet to be characterized, was fractionated by HPLC, and the output from the unit was introduced into the rat heart bioassay system directly. The on line HPLC-rat heart bioassay system detected the active fraction from approximately 20 substances in the partially purified plasma. This system enabled rapid and reproducible identification of the active vasoconstrictor in plasma.     

High Pressure Liquid Chromatography of Selected Sulfur Compounds

Abstract

High pressure liquid chromatography was used to separate and determine quantitatively the following groups of sulfur compounds: thiols, sulfides, disulfides, sulfones, isothiocyanates, thioamides, and thioureas. Amperometric and UV detectors were compared; for thiols, thioureas, isothiocyanates, and thioamides, the former was generally more sensitive. With the exception of alkyl and cycloalkyl sulfides, the liquid chromatographic method can be used for the analysis of the investigated sulfur compounds below the ppm range. The method developed was compared to gas chromatography with flame photometric detection. The latter was found to be superior for the analysis of alkyl and cycloalkyl thiols, sulfides and disulfides of molecular weight below 200, whereas the former was more suitable for the analysis of aromatic thiols, sulfides and disulfides, as well as thioamides, isothiocyanates, and thioureas. Both methods were equivalent for the analysis of aromatic sulfones.     

High Pressure Liquid Chromatography of Thyromimetic Iodoamino Acids

Abstract

The chromatographic properties of 16 thyromimetic iodoamino acids and related compounds on microparticulate non-polar stationary phases have been examined and conditions determined which allow optimised resolution with analysis time ca. 60 minutes. These compounds elute in order of increasing hydrophobicity which correlates with the progressive increase in the number of iodogroups present in the tyrosine or thyronine aromatic nucleus. The reverse isomers, e.g. rT3, have consistently greater k' values than their corresponding analogues, e.g. T3. Conditions for the direct application of the rapid HPLC analyses of the iodoamino acids in biological or pharmaceutical samples have been examined.     

Application of High Pressure Liquid Chromatography to the Forensic Analysis of Several Benzodiazepines

Abstract

Eleven benzodiazepines are separated and measured by an HPLC adsorption system utilizing isocratic elution combined with dual wavelength detection at 254 nm and 280 nm. Powder and solid dosage forms of 10 benzodiazepines are simply ground and then extracted with chloroform and injected. Clorazepate dipotassium is not soluble in chloroform and is decarboxylated to N-desmethyldiazepam.     

An Organic Nitrogen Specific Detector for High Pressure Liquid Chromatography

Abstract

The Thermal Nitrogen Analyzer (TNA), a new highly sensitive and nitrogen-selective detector for high pressure liquid chromatography, is described.     

糖胺多糖酶解产物—不饱和二糖的高效液相色谱分析

介绍了一种糖胺多糖的二糖组成成分分析方法－高效液相色谱法。该方法柱前处理简单。应用该方法对人体尿液中糖胺多糖的二糖组成进行了分析     

Analysis of Coloured Chlorhexidine Solutions by Ion-Pairing Reverse-Phase High Pressure Liquid Chromatography

Abstract

An isocratic, high pressure liquid chromatographic procedure is described for the analysis of mixtures of chlorhexidine acetate and tartrazine, carmoisine or methylene blue. The method uses an ion-pairing reverse-phase technique which can be performed in less than 30 minutes.     

The Clever Use of Pressure in Column Liquid Chromatography

The pressure limits of a liquid chromatographic instrument can be maxed out by running the separation at the highest possible flow rate. This approach reduces analysis time but it does not save solvent and the separation will be poorer due to the properties of the van Deemter curve. Thus, it is better to use a shorter column with smaller particle size because both analysis time and solvent consumption will decrease while the resolution will remain constant. This paper shows how to utilize the pressure which is offered by a certain LC instrument in a clever way. It explains the algebraic background and illustrates the validity of the approach with two analytical problems, namely the separation of seven doping agents and of six drugs.     

Determination of Amikacin Isomers by High Pressure Liquid Chromatography

Abstract

A high-pressure liquid chromatographic (HPLC) method for quantitative monitoring of amikacin isomers is described. Four isomers, BB-K8, BB-K29, BB-K6 and BB-K11 were applied to a silica gel column. While adsorbed, the isomers were derivatized with o-phthalaldehyde and the derivatized products eluted with ethanol. A decrease in the fluorescence of the derivatized products with time was observed. Heating at 50°C for 5 min produced products with stable fluorescence for at least three hours. Using the fluorescent properties of the amikacin derivative for detection, the four isomers of amikacin were separated by reverse phase (HPLC). A linear relationship from 1 to 10 μg/mL was obtained for all four isomers.     

Separation of Methylated Purines by High Pressure Liquid Chromatography

Abstract

This paper reports a method for the separation and measurement of methylated purines of interest to carcinogenesis studies by high-pressure liquid chromatography (HPLC) following their column chromatographic isolation from collected urine samples. HPLC was evaluated on three different cation-exchange columns, with optimum conditions obtained on a Partisil 10-SCX column employing isocratic elution with 0.25M (NH₄)H₂PO₄ at pH 4.0. This column was also found to be useful for the separation of mono-methylguanine isomers. Application is shown to the analysis of rat urine following animal treatment with methyl methanesulfonate.     

痕量神经肽的高效液相色谱

本文选用芴甲氧羰基氯(FMOC-CL)作为肽的荧光衍生试剂,建立了两段淋洗分离测定神经肽RP-HPLC的方法。衍生反应简便、快速、衍生物稳定。FMOC-脑啡肽、FMOC-P物质在18min内全部被洗脱。本方法在1～100pmol具有良好的定量线性关系。当信噪比为2.5:1时,检测极限:FMOC-甲硫脑啡肽为405fmol,FMOC-亮脑啡肽337fmol,FMOC-P物质为500fmol。并且能够容易地脱去衍生基团得到反应前的神经肽。     

Determination of Pentachlorophenol Laurate by High Pressure Liquid Chromatography

Abstract

Pentachlorophenol Laurate (PCPL) in canvas is determined by extraction and chromotography on silica gel. Conditions are chosen to eliminate peak splitting due to the presence of different “laurate” fatty acids. The determination is faster and more specific than previously reported methods.     

Separation of Biological Pyridines by High Pressure Liquid Chromatography

Abstract

The separation of the six pyridine compounds which comprise the pyridine nucleotide cycle, nicotinamide adenine dinucleotide phosphate and para-aminobenzoic acid, a compound biologically related to these pyridines, can be achieved rapidly utilizing high pressure liquid chromatography. Optimum separation is accomplished using ion-ion pairing in reverse phase chromatography with a C₁₈ stationary phase and an aqueous mobile phase of 5mM pentanesulfonic acid and 25 mM KH₂PO₄. The effect of temperature on the separation is minimal. As little as 10 ng of these compounds is detected via absorption of ultraviolet light at a wavelength of 254 nm.     

Analysis of Monophenol Oxidase Activity Using High Pressure Liquid Chromatography with Electrochemical Detection

Abstract

A very sensitive, specific and reliable quantitative assay was developed for measuring the rate of hydroxylation of tyrosine by mushroom tyrosinase using high pressure liquid chromatography with electrochemical detection (HPLC-ED). The assay employs N-acetyldopamine (NADA) as cofactor and ascorbate as a reducing agent. The product of the reaction, L-dopa (3,4-dihydroxyphenylalanine), was readily separated by HPLC-ED from the remaining interacting components. The reaction was linear with time and proportional to the amount of enzyme present. The amount of ascorbate gradually decreased during the hydroxylation of tyrosine, but as long as ascorbate was present in the reaction mixture the levels of L-dopa and NADA were not altered. The data     

Synergistic Use of Countercurrent Chromatography and High Performance Liquid Chromatography for the Purification of Synthetic Peptides

Abstract

Examples are given demonstrating how countercurrent chromatography (CCC) and high performance liquid chromatography (HPLC) can be used together to purify synthetic peptides. In one example, CCC provided a preliminary purification of Met-Arg-Asp-Val-Val-Leu-Phe-Glu-Lys by enabling separation of ultraviolet absorbing, ninhydrin-negative material from the desired peptide. Final purification was achieved with HPLC without risk of harming the HPLC column. In a second example Tyr-Ala-Ala-Nle-Ala-Ala was completely purified by CCC with the CCC separation rapidly and conveniently monitored by HPLC. CCC appears to be a very useful technique for the peptide chemist.     

Separation of Tetrahydrocannabinol Isomers by Reverse-Phase High Pressure Liquid Chromatography

Abstract

The separation of three closely related tetrahydrocannabinol isomers differing only in the position of the double bond in ring C was achieved by HPLC using a μBondapak C18 column and a ternary mobile phase of acetonitrile/tetrahydrofuran/water. Near base line resolution was obtained on the first pass through the column and complete resolution was accomplished after one recycle.     

Separation of Xanthine Derivates by High Pressure Liquid Chromatography and Application to Plasma Analysis

Abstract

High pressure liquid chromatography (HPLC) methods were developed for separation and plasma analysis of ten xanthine derivates. Separation was evaluated on silica column and on three different reverse phase columns, with optimum conditions obtained on C₆ spherisorb column using isocratic elution with phosphate buffer 10^?2 M, pH 2.7 - acetonitrile mixture (80/20 V/V). Determination of these xanthine derivates in plasma for therapeutic control was studied.