title: Differential amperometric determination of hydrogen peroxide in honeys using flow-injection analysis with enzymatic reactor.
abstract: Hydrogen peroxide (H2O2) present in honey was rapidly determined by the differential amperometric method in association with flow-injection analysis (FIA) and a tubular reactor containing immobilized enzymes. A gold electrode modified by electrochemical deposition of platinum was employed as working electrode. Hydrogen peroxide was quantified in 14 samples of Brazilian commercial honeys using amperometric differential measurements at +0.60V vs. Ag/AgCl((sat)). For the enzymatic consumption of H2O2, a tubular reactor containing immobilized peroxidase was constructed using an immobilization of enzymes on Amberlite IRA-743 resin. The linear dynamic range in H2O2 extends from 1 to 100 x 10(-6) mol L(-1), at pH 7.0. At flow rate of 2.0 mL min(-1) and injecting 150 microL sample volumes, the sampling frequency of the 90 determinations per hour is afforded. This method is based on three steps involving the flow-injection of: (1) the sample spiked with a standard solution, (2) the pure sample and (3) the enzymatically treated sample with peroxidase immobilized. The reproducibility of the current peaks for hydrogen peroxide in 10(-5) mol L(-1) range concentration showed a relative standard deviation (R.S.D.) better than 1%. The detection limit of this method is 2.9 x 10(-7) mol L(-1). The honey samples analyses were compared with the parallel spectrophotometric determination, and showed an excellent correlation between the methods.
authors: NUPIS (Núcleo de Pesquisa em Instrumentação e Separações Analíticas), Departamento de Química, Instituto de Ciências Exatas, Universidade Federal de Juiz de Fora, 36036-330 Juiz de Fora, MG, Brazil.
authors: Rômulo Augusto de Abreu
authors: RA
authors: Franchini
authors: Maria Auxiliadora Costa
authors: MA
authors: Matos
authors: Rosana
authors: R
authors: Colombara
authors: Renato Camargo
authors: RC
authors: Matos
mesh_terms: D004553:Electric Conductivity; D004563:Electrochemistry / Q000295:instrumentation* / Q000379:methods*; D004800:Enzymes, Immobilized; D017022:Flow Injection Analysis / Q000379:methods*; D006722:Honey / Q000032:analysis*; D006861:Hydrogen Peroxide / Q000737:chemistry*; D009195:Peroxidase / Q000378:metabolism
chemical_list: D004800:Enzymes, Immobilized; D006861:Hydrogen Peroxide; D009195:Peroxidase