POSTCOLUMN IMMOBILIZED TYROSINASE REACTOR FOR DETERMINATION OF L-3,4-DIHYDROXYPHENYLALANINE AND L-TYROSINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION
N. Kiba et al., POSTCOLUMN IMMOBILIZED TYROSINASE REACTOR FOR DETERMINATION OF L-3,4-DIHYDROXYPHENYLALANINE AND L-TYROSINE BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY WITH FLUORESCENCE DETECTION, Journal of chromatography, 648(2), 1993, pp. 481-484
Immobilized tyrosinase was used as a reactor in a liquid chromatograph
ic system for the selective detection Of L-3,4-dihydroxyphenylalanine
(L-DOPA) and L-tyrosine. Tyrosinase was immobilized on controlled-pore
glass beads. The compounds were separated on an ODS column with 0.1 M
phosphate buffer (pH 7.2) as mobile phase. The fluorescent dihydroxyi
ndol formed was detected at 490 nm (excitation at 360 nm). For L-DOPA
the linear working range was 0.005-15 muM, with a detection limit of 1
nM (6 pg in a 30-mul injection); for L-tyrosine the range was 0.01-30
muM, with a detection limit of 5 nM (27 pg in a 30-mul injection). Th
e reactor was stable for at least 2400 injections. Its usefulness for
simultaneous determination Of L-DOPA and L-tyrosine in serum is descri
bed.