Determination of biologically active low-molecular-mass thiols in human blood. III. Highly sensitive narrow-bore isocratic reversed-phase high-performance liquid chromatography with fluorescence detection.

The fast isocratic narrow-bore reversed-phase high-performance liquid chromatographic method employing fluorescence detection is described for the precise reproducible simultaneous measurement of total homocysteine, cysteine and glutathione in human blood. Sample preparation involves conversion of disulfides to free thiols with triphenylphosphine, precipitation of proteins with sulfosalicylic acid, and conjugation of thiols with monobromobimane. Optimized sample preparation conditions as well as chromatographic conditions allowed to obtain reliable quantitative results within the concentration range corresponding to the levels of these thiols in human blood in norm and pathology.

Direct determination of amino acids and carbohydrates by high-performance capillary electrophoresis with refractometric detection.

This is an initial report to propose a novel approach in high-performance capillary electrophoresis (HPCE) for the direct detection of compounds without natural absorbance in the UV and visible spectral range, such as amino acids and carbohydrates. A refractometry detector with the 2 nl cell (Applied Systems, Minsk, Belarus) was employed to identify amino acids and carbohydrates without derivatization. The first results are provided on separation of seven free amino acids in the phosphate running buffer and three free carbohydrates in the borate-sodium dodecyl sulfate running buffer and detection by refractometer.