Precise method for the measurement of catalase activity in honey.
An improved method is reported for the determination of catalase activity in honey. We tested different dialysis membranes, dialysis fluid compositions and amounts, dialysis temperatures, sample amounts, and dialysis times. The best results were obtained by dialysis of 7.50 g sample in a cellulose dialysis sack, using two 3 L portions of 0.015 M sodium phosphate buffer (pH 7.0) as the dialysis fluid at 4 degrees C for 22 h. As in previous methods, catalase activity was determined on the basis of the rate of disappearance of the substrate, H202, with the H202 determined spectrophotometrically at 400 nm in an assay system containing o-dianisidine and peroxidase. Trials indicated that the best solvent for the o-dianisidine was 0.2 M sodium phosphate buffer, pH 6.1; the best starting H202 concentration was 3 mM; the best HCl concentration for stopping the reaction was 6 N; and the best sample volume for catalase measurement was 7.0 mL. Precision values (relative standard deviations for analyses of 10 subsamples of each of 3 samples) were high, ranging from 0.48% for samples with high catalase activity to 1.98% for samples with low catalase activity.
Huidobro
José F
JF
Universidad de Santiago de Compostela, Area de Nutrición y Bromatología, Departamento de Química Analítica, Nutrición y Bromatología, Facultad de Farmacia, Campus Universitario Sur, E-15782 Santiago de Compostela, Spain. qnhuidob@usc.es
Sánchez
M Pilar
MP
Muniategui
Soledad
S
Sancho
M Teresa
MT
D002021:Buffers; D002138:Calibration; D002374:Catalase / Q000032:analysis* / Q000378:metabolism; D002384:Catalysis; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003956:Dialysis; D003962:Dianisidine / Q000032:analysis; D006722:Honey; D006861:Hydrogen Peroxide / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008566:Membranes / Q000378:metabolism; D009195:Peroxidase / Q000032:analysis; D010710:Phosphates / Q000737:chemistry; D015203:Reproducibility of Results; D012107:Research Design; D013053:Spectrophotometry; D013696:Temperature; D013997:Time Factors
D002021:Buffers; D010710:Phosphates; D006861:Hydrogen Peroxide; D002374:Catalase; D009195:Peroxidase; D003962:Dianisidine; C018279:sodium phosphate