title: Separation and determination of L-tryptophan and its metabolites by capillary micellar electrokinetic chromatography with amperometric detection.
abstract: A high-performance method of capillary micellar electrokinetic chromatography (CMEKC) with amperometric detection (AD), using a newly designed pre-aligned electrochemical cell, has been developed for the separation and determination of L-tryptophan (Trp) and its eight metabolites including 3-hydroxy-L-kynurenine (3-HK), 5-hydroxy-L-tryptophan (5-HTP), L-kynurenine (KN), 5-hydroxyindole-3-acetic acid (5-HIAA), xanthurenic acid (XA), indole-3-pyruvic acid (IPA), 5-hydroxytryptamine (5-HT), and tryptamine (Tryp). A carbon disk electrode was used as the working electrode and the optimal detection potential was 0.85 V (versus Ag/AgCl). At 24 kV of applied voltage, the nine compounds were completely separated, within 23 min, in a 10 mol/L Na(2)HPO(4)-NaOH buffer (pH 11.0) containing 40 mmol/L sodium dodecyl sulfate (SDS) and 3% methanol (v/v). A good linear relationship was obtained for all analytes in this paper and the detection limits of 3-HK, 5-HTP, KN, Trp, 5-HIAA, XA, IPA, 5-HT, and Tryp were 7.42, 5.18, 34.6, 3.99, 15.1, 12.7, 260, 6.72, and 8.01 nmol/L, respectively. This method has been applied to analyze the metabolism of Trp in rabbit urine.
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Qiu
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Xu
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
authors.forename: Lan
authors.initials: L
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Fuzhou University, Fuzhou, Fujian, China.
authors.forename: Guonan
authors.initials: G
authors.lastname: Chen
mesh_terms: D000818:Animals; D002021:Buffers; D020374:Chromatography, Micellar Electrokinetic Capillary / Q000379:methods*; D019075:Electrophoresis, Capillary / Q000379:methods; D006863:Hydrogen-Ion Concentration; D011199:Potentiometry / Q000379:methods; D011817:Rabbits; D012680:Sensitivity and Specificity; D014364:Tryptophan / Q000302:isolation & purification* / Q000378:metabolism* / Q000493:pharmacokinetics / Q000652:urine
chemical_list: D002021:Buffers; D014364:Tryptophan
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