High-speed analysis of catecholamines in plasma by medium-pressure mu-LC with an amperometric detector.

A high-speed highly sensitive and reproducible method for the determination of catecholamines in small plasma volumes has been developed. Catecholamines were separated on a short capillary fused-silica column (0.32 mm i.d.) packed with a reverse-phase sorbent with a particle size of 10 microns. The time of a single chromatographic analysis was less than 6 min, and the operating pressure in the system was not higher than 5.0 MPa. The required volume of blood plasma was 0.5 mL. When a 10 microL sample previously concentrated on alumina was injected into the column, the limits of amperometric detection for noradrenaline (NA), adrenaline (A), 3,4-dihydroxy-benzylamine (DHBA), and dopamine (DA) were 3.9, 2.6, 1.8 and 5.6 ng/L, respectively. The average variation coefficient was 17.4%.