Flow-injection determination of l-tyrosine in serum with immobilized tyrosinase.
A flow-injection method for the determination of the serum l-tyrosine is described. The method involves the conversion of tyrosine into dopaquinone by reaction of tyrosinase, followed by derivation of the dopaquinone with fluorogenic agent 1,2-diphenylethylenediamine. Serum was deproteinized with tungstic acid. Sample solution was injected into a reactor (50 x 4 mm i.d.) packed with glass beads on which tyrosinase was immobilized. The fluorescence was detected at 480 nm (excitation at 350 nm). The calibration graph was linear for 5 x 10(-7)-2 x 10(-4)Ml-tyrosine; the detection limit was 2 x 10(-7)M.
Kiba
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Department of Applied Chemistry and Biotechnology, Faculty of Engineering, Yamanashi University, Kofu 400, Japan.
Suzuki
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Furusawa
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