[THE SIMULTANEOUS ANALYSIS OF FREE CATECHOLAMINES AND METANEPHRTNES IN URINE USING TECHNIQUE OF HIGHLY EFFECTIVE LIQUID CHROMATOGRAPHY WITH FLUORIMETRIC DETECTION AND SOLID PHASE EXTRACTION ON POLYMERIC SORBENT (PUROSEP-200)].

The article considers the technique of simultaneous detection of free catecholamines and free metanephrines in urine using inverse phase highly effective liquid chromatography with fluorimetric detection. The solid phase extraction was implemented on cartridges with 30 mg of hyper cross-linked polystyrene (Purosep-200). The simplicity, reproducibility and sufficient sensitivity of technique permit applying it in clinical practice to diagnose pheochromocytoma.

[HPLC analysis of dehydroepiandrosterone sulfate in serum with use of solid-phase extraction on hyper cross-linked polystyrene (Purosep-200)].

We have developed a simple HPLC method for analysis of the dehydroepiandrosterone sulfate (DHEA-sulfate) in serum with use a new procedure of solid-phase extraction (SPE) on hyper cross-linked polystyrene (Purosep-200) and fast chromatographic separation on the monolithic column under isocratic elution and UV detection at 200 nm. Complete SPE procedure lasts for about 7 min, chromatographic separation takes less than 6 min. Simplicity and high reproducibility of this method makes it attractive in routine clinical practice.

[The HPLC analysis of vanillil-almond, 5-hydroxiindolacetic, homovanillic and homogentisic acids in biologic fluids in clinical laboratory].

The simple and fast HPLC technique of analysis of vanillil-almond, 5-hydroxiindolacetic, homovanillic and homogentisic acids in urine with solid-phase extraction using ultra cross-linked polystyrene (Purosep-200) is proposed. The separation on column Chromolith Performance RP-18e "Merck" 100x4.6 mm with monolithic phase-reversed silica gel in isocratic or gradient mode with ultraviolet detection under 285 nm. The isocratic mode is applied in case of ordinary analysis of vanillil-almond or homogentisic acids. The composition of eluent is isopropanol - water - TFA (1:99:0.025, v/v/v), flow speed is 1400 mkl/min; pressure is 37 bar, full separation less than in 4 min. The gradient low pressure mode is applied to analyze vanillil-almond, hydroxiindolacetic and homovanillic acids. Under this approach the switching to second eluent occurred from second minute. The composition of eluent is isopropanol-water-TFA (6:94:0.025, v/v/v), flow speed is 1400 mkl/min, pressure is 43 bar, full separation is less than in 7 min. The output (extraction share) consisted 78-113%. The simplicity reproducibility and sufficient sensitivity of technique in combination with the possibility of its application on standard chromatographic equipment (isocratic pump and ultraviolet detector) made it useful for routine clinical application.