title: Simultaneous voltammetric determination of paracetamol and caffeine in pharmaceutical formulations using a boron-doped diamond electrode.
abstract: A simple and highly selective electrochemical method was developed for the single or simultaneous determination of paracetamol (N-acetyl-p-aminophenol, acetaminophen) and caffeine (3,7-dihydro-1,3,7-trimethyl-1H-purine-2,6-dione) in aqueous media (acetate buffer, pH 4.5) on a boron-doped diamond (BDD) electrode using square wave voltammetry (SWV) or differential pulse voltammetry (DPV). Using DPV with the cathodically pre-treated BDD electrode, a separation of about 550 mV between the peak oxidation potentials of paracetamol and caffeine present in binary mixtures was obtained. The calibration curves for the simultaneous determination of paracetamol and caffeine showed an excellent linear response, ranging from 5.0 x 10(-7)mol L(-1) to 8.3 x 10(-5)mol L(-1) for both compounds. The detection limits for the simultaneous determination of paracetamol and caffeine were 4.9 x 10(-7)mol L(-1) and 3.5 x 10(-8)mol L(-1), respectively. The proposed method was successfully applied in the simultaneous determination of paracetamol and caffeine in several pharmaceutical formulations (tablets), with results similar to those obtained using a high-performance liquid chromatography method (at 95% confidence level).
authors.affiliation: Instituto de Química de São Carlos, Universidade de São Paulo, C.P. 780, 13560-970 São Carlos, SP, Brazil.
authors.forename: Bruna Cláudia
authors.initials: BC
authors.lastname: Lourenção
authors.forename: Roberta Antigo
authors.initials: RA
authors.lastname: Medeiros
authors.forename: Romeu C
authors.initials: RC
authors.lastname: Rocha-Filho
authors.forename: Luiz Henrique
authors.initials: LH
authors.lastname: Mazo
authors.forename: Orlando
authors.initials: O
authors.lastname: Fatibello-Filho
mesh_terms: D000082:Acetaminophen / Q000032:analysis*; D001895:Boron; D002110:Caffeine / Q000032:analysis*; D002138:Calibration; D018130:Diamond; D004566:Electrodes; D011199:Potentiometry / Q000295:instrumentation / Q000379:methods*; D013607:Tablets / Q000032:analysis
chemical_list: D013607:Tablets; D000082:Acetaminophen; D002110:Caffeine; D018130:Diamond; D001895:Boron