Rapid isocratic high-performance liquid chromatography of porphyrin esters on aminopropyl-bonded silica

High-performance liquid chromatographic determination of zinc protoporphyrin and porphyrin carboxylic acids in urine

A method for the reversed-phase high-performance liquid chromatographic separation of zinc protoporphyrin and porphyrin carboxylic acids with fluorescence detection and its application are described. A mu Bondapak C18 column was employed for all the experiments in this study. The method required a pretreatment of the column with a two-component mobile phase containing 0.1 M NaH2PO4 in acetonitrile (28:15, v/v, pH 5.3) for 10 min prior to sample injection. Separation was achieved isocratically by increasing the concentration of acetonitrile in the mobile phase (0.1 M NaH2PO4:acetonitrile, 18:130, v/v, pH 5.3) 4 min after injection to complete the elution. The flow rates and the period of pretreatment of the column were studied to optimize the separation. The method was applied to determining zinc protoporphyrin and porphyrin carboxylic acids of heme biosynthesis in urine.

High-performance liquid chromatography of porphyrins

Techniques for the analysis of porphyrins in the biomedical fields are reviewed. The emphasis is on high-performance liquid chromatography and its aspplications in: (1) the quantitative analysis of porphyrins in blood, urine and faeces; (2) qualitative porphyrin profiles in normal subjects and in the porphyrias; (3) assay of haem biosynthetic enzyme activities and (4) resolution of type isomers of porphyrins and porphyrinogens. Detection systems, quantitation methods, peak identification and sample preparation procedures are discussed.

Porphyrinostatic effect of isonicotinic acid hydrazide on porphyric chick embryo and yeast

1. The common feature of "inducible" forms of hepatic porphyria is an increased activity of delta-amino-levulinate/ALA/synthase. 2. As a potential therapeutic procedure, isonicotinic acid hydrazide/INH/as inhibitor of this enzyme, was applied and found to show a porphyrinostatic effect, depending on its concentration, both in yeast and porphyric chick embryo models. 3. Moreover, pyridoxalphosphate/PDX/eliminated the porphyrinostatic effect of INH, depending again on its concentration. 4. Histochemical tests did not demonstrate any significant functional or morphological changes in the chick embryo hepatocytes following INH administration.

Normal-phase high-performance liquid chromatography of free acid dicarboxylic porphyrins and hematoporphyrin derivative on silica

The isocratic separation of dicarboxylic porphyrins (hematoporphyrin, hydroxyethylvinyl-deuteroporphyrin and protoporphyrin) and their isomers by normal-phase high-performance liquid chromatography is described. The stationary phase is unmodified silica and the mobile phase consists of acetone-ethyl acetate (1:1, v/v) mixtures containing water and inorganic acids. Retention (capacity factor, k') was found to decrease exponentially with the mole fraction of water (NH2O) and to increase linearly with the concentration of hydrochloric acid, following the relation k' = A [HCl] NH2O-4.85, where A is a constant characteristic of the porphyrin. The effects of the concentration and the nature of the acid used strongly suggest that retention involves a form of the porphyrin in which the inner nitrogens are protonated. The retention is thus partly determined by the basicity of the inner nitrogens, which depends on the electron-donating power of the porphyrin side-chains. Good resolution of the various components of hematoporphyrin derivative was obtained. In comparison with reversed-phase chromatography this method shows a different retention mechanism, appears to yield results of comparable reproducibility and provides complementary information. Possible retention mechanisms based on partition or adsorption equilibria are discussed.

Solid phase extraction and isocratic separation of urinary porphyrins by HPLC

A method for determining urine porphyrins by HPLC is described. In the preliminary step, porphyrins are purified in high yields and concentrated by low pressure reverse-phase chromatography on C18 (octadecylsilane bonded silica) cartridge. Porphyrins are stable for 10 days after adsorption on C18 cartridge. The separation of porphyrin esters is performed on an aminopropyl-bonded silica column with an eluting system containing n-heptane and ethyl acetate. The system enables rapid isocratic separation of porphyrin methyl esters with high selectivity. The simplicity and reproducibility of the whole procedure allows its application to the routine analysis of urinary porphyrins in the clinical laboratory.