Differential amperometric determination of hydrogen peroxide in honeys using flow-injection analysis with enzymatic reactor.
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.
Franchini
Rômulo Augusto de Abreu
RA
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.
Matos
Maria Auxiliadora Costa
MA
Colombara
Rosana
R
Matos
Renato Camargo
RC
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
D004800:Enzymes, Immobilized; D006861:Hydrogen Peroxide; D009195:Peroxidase