Inhibitive Kinetic Spectrophotometric Determination of Traces of Protein Using m-Acetylchlorophosphonazo as an Indicator

Abstract

A novel kinetic spectrophotometric method for the determination of protein is developed based on the inhibitory effect of bovine serum albumin (BSA) on the oxidation reaction of m-acetylchlorophosphonazo (CPAmA) by potassium periodate. In the medium of 6 × 10^-3 mol L^-1 sulfuric acid and at maximum absorption peak of 550 nm, the absorbance difference (DA) is linearly related with the concentration of bovine serum albumin over the range of 0.20-6.0 μg/mL of solution and fitted the equation: DA = 0.1105C (C: μg mL^-1) + 0.0115, with a regression coefficient of 0.9936. The detection limit of the method was 0.028 μg mL^-1. The method was used to determine protein in white egg. The relative standard deviation was 3.13 % for 13 replicate determinations. The recovery of the standard addition was 103.7 %. The operation of the method is simple, fast and of high sensitivity and the linear range is wide, so it is suitable for the determination of protein.