Kinetic Method for Determination of Trace Amounts of Protein Based on its Inhibitive Effect on Potassium Periodate-(Dibromo-p-sulfonic acid arsenazo) Indicator Reaction

A novel kinetic spectrophotometric method for the determination of protein is based on the inhibitive effect of bovine serum albumin (BSA) on the oxidation reaction of dibromo-p-sulfonic acid arsenazo (DBS-ASA) by potassium periodate in the medium of CH2ClCOOH-CH3COONH4. The maximum absorption peak of BSA-(DBS-ASA)-KIO4 system is located at 530 nm. The absorbance difference (Delta A) is well linearly related with the concentration of bovine serum albumin over the rage of 2.5-90.0 mu g/mL of solution and fitted the equation: Delta A = 0.01091C + 0.0646 (C: mu g/mL), with a correlation coefficient gamma = 0.9941. The detection limit of the method was 0.48 mu g/mL. The method has been successfully used in the determination of the total content of protein in egg white and the relative standard deviation of 15 determinations were less than 5 %. The recovery of standard addition of the method was over the range of 100.1-101.2%.