title: The use of carbon paste electrode in the direct voltammetric determination of tryptophan in pharmaceutical formulations.
abstract: A simple, fast and sensitive method is proposed for Tryptophan (Trp) determination in pharmaceutical formulations containing other non-electroative aminoacids, vitamins and hydroxycobalamines. Optimized conditions for differential pulse voltammetry allowed the determination of Trp with detection limit of 1.7 microM in 2-30 mM linear dynamic range (n=7; r=0.999), at a bare, non-treated carbon paste electrode. Ascorbic acid interference was evaluated and eliminated by choosing a suitable baseline for determination of peak currents for Trp.
authors.affiliation: Departamento de Química, Universidade Federal de São Carlos, Via Washington Luís, km 235, CxP 676, CEP 13565-905, SP, São Carlos, Brazil.
authors.forename: Antonio Rogério
authors.initials: AR
authors.lastname: Fiorucci
authors.forename: Eder Tadeu Gomes
authors.initials: ET
authors.lastname: Cavalheiro
mesh_terms: D001205:Ascorbic Acid / Q000737:chemistry; D002021:Buffers; D002244:Carbon; D004338:Drug Combinations; D004563:Electrochemistry; D004566:Electrodes; D007202:Indicators and Reagents; D013607:Tablets; D014364:Tryptophan / Q000032:analysis*
chemical_list: D002021:Buffers; D004338:Drug Combinations; D007202:Indicators and Reagents; D013607:Tablets; D002244:Carbon; D014364:Tryptophan; D001205:Ascorbic Acid