Rmv. Camanas et al., ANALYSIS OF PHARMACEUTICAL PREPARATIONS CONTAINING CATECHOLAMINES BY MICELLAR LIQUID-CHROMATOGRAPHY WITH SPECTROPHOTOMETRIC DETECTION, Analyst, 120(6), 1995, pp. 1767-1772
An HPLC procedure for the determination of catecholamines (CAs) and ot
her compounds which are associated with CAs in pharmaceutical preparat
ions is described. A sodium dodecyl sulfate (SDS) micellar mobile phas
e, a C-18 column and spectrophotometric detection at 280 nm were used.
A mobile phase containing 0.1 mol l(-1) SDS, 0.67 mol l(-1) (5% v/v)
propanol and buffered with phosphate at pH 3 is recommended. The CAs g
ave limits of detection in the 4-7 ng ml(-1) range. The procedure was
applied to the determination of L-dopa, 2-methyldopa, epinephrine, dop
amine and isoproterenol, as well as other compounds frequently associa
ted with CAs in pharmaceuticals including phenylephrine, carbidopa and
hydrochlorothiazide. The solute-micelle association constants and the
partition constants of the CAs between the stationary phase and water
in several media, and the protonation constants of L-dopa and 2-methy
ldopa, were evaluated from chromatographic data.