A.E. Claeys

High-performance liquid chromatographic assay of vitamin K in human serum.

A sensitive combined adsorption and reversed-phase high-performance liquid chromatographic procedure is described that permits the determination of endogenous vitamin K1 levels in serum. The separation of vitamin K1 (cis- + trans-isomers), vitamin K1 epoxide and the menaquinones MK-2, MK-4 and MK-9 by adsorption, reversed-phase and cyano-bonded phase chromatography is discussed. The methodology was further developed for the quantitative measurement of vitamin K1 in human serum. Concentrations as low as 500 pg/ml in serum could be detected. The identity of the vitamin K1 peak was confirmed by UV absorption spectrophotometry and re-chromatography. The method has been applied to the determination of serum levels in normal healthy individuals and patients treated with vitamin K1.

Plasma vitamin A in haemodialysis patients

Different high performance liquid chromatographic systems were applied to the investigation of vitamin A metabolism in subjects undergoing haemodialysis. Plasma levels of retinol, retinyl esters and retinoic acid were measured. There was a significant elevation of plasma retinol and dialysis failed to normalise this level. No correlation with plasma concentrations of creatinine or urea was found. No differences in retinyl ester and retinoic acid levels were observed between healthy subjects and haemodialysis patients. These results suggest that retinol accumulation is not caused by a deficiency in its oxidative metabolism.

Thin-layer chromatography of hydrazidic monoamine oxidase inhibitor drugs.

Seven solvent systems for the thin-layer chromatographic separation of hydrazidic monoamine oxidase inhibitor drugs have been developed. Detection of compounds at the microgram level was performed with the aid of thirteen spray reagents.

Improved Column Systems for Gas-Liquid Chromatography of Iproniazid and Iproclozide

As a result of a comparative study performed on thirteen liquid phases an improved set of four analytically packed columns, i.e., Versamid-900, Versamid-930, XE-60, and OV-225 is withheld for successful gas chromatography of iproniazid and iproclozide. Retention data in terms of adjusted retention times and relative retentions, using structurally related compounds as reference, are reported. An evaluation of gas chromatographic performance of proposed columns is described.