Y. Tsuruta, H. Inoue
Dec 1, 1998
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0
Influential Citations
23
Citations
Journal
Analytical biochemistry
Abstract
A highly sensitive fluorescent labeling reagent, 4-(5,6-dimethoxy-2-phthalimidinyl)-2-methoxyphenylsulfonyl chloride (DMS-Cl), for determination of amino acids by HPLC has been developed. DMS-Cl reacted with amino acids in the basic medium to produce the corresponding fluorescent sulfonamides (excitation and emission wavelength: 318 and 406 nm in aqueous acetonitrile, respectively). When the reactivity of DMS-Cl was investigated by means of reversed-phase HPLC using hydroxyproline (Hyp) and alanine (Ala) as model compounds, the reaction of Hyp was completed within 5 min at 25 degrees C and that of Ala within 15 min at 70 degrees C. The efficiency of conversion of Hyp into the fluorescent derivative was about 100%. The detection limits (signal-to-noise ratio = 3) of almost all amino acids were less than 5 fmol/injection. When the concentration of urinary free Hyp was measured with HPLC using DMS-Cl, the concentration (mean +/- SD, n = 10) was 3.8 +/- 2.76 microM (2.7 +/- 1.71 nmol/mg creatinine).