Jms. Mallols et al., DETERMINATION OF CATECHOLAMINES AS AMINOCHROMES BY MICELLAR LIQUID-CHROMATOGRAPHY WITH THERMAL LENS SPECTROPHOTOMETRIC DETECTION, Chromatographia, 38(5-6), 1994, pp. 365-372
The determination of catecholamines (CAs) using micellar liquid chroma
tography with thermal lens spectrophotometric detection has been studi
ed. CAs are oxidized with hexacyanoferrate(III) to aminochromes which
are separated with a mobile phase of 0.05 M sodium dodecyl sulphate, 7
% propanol and 0.03 M citrate buffer, pH 4.8, on a partially endcappe
d C-18 column. The aminochrome-micelles and aminochrome-stationary pha
se association constants are evaluated. Using the 488 nm line of an Ar
+ laser with 250 mW pump power the limits of detection are about 4 ng
mL-1. The technique is applied to the determination of unconjugated CA
s in urine using isoproterenol as internal standard.