Abstract:

A novel spectrophotometric method for the determination of protein was proposed based on the fact that in the presence of OP100, chlorophosphonazoⅢ（CPAⅢ） and bovine serum albumin （BSA） can react quickly to generate a composite under acidic conditions that shows a characteristic absorption peak by which protein can be accurately detected  with spectrophotometry. At 674 nm, （CPAⅢ）BSA composite  has a maximum absorption. The absorbance difference （Δ A） is linearly related with the concentration of BSA over a range of 0—300 μg/mL and the fitted equation is Δ A=0.003 1ρ+0.003 9 （ρ： μg/mL）, with a correlation coefficient r=0.996 4. The detection limit of the method was 1.55 μg/mL. The proteins in human serum and egg albumen samples were successfully determined by this method. The relative standard deviation was 2.43%—4.35%. The recovery of standard addition of the method was 97.97%—103.07%.

Key words: chlorophosphonazoⅢ, spectrophotometry, protein