ABSTRACT
A turbid solution was formed through the reaction between ?-PGA and cetylpyridinium chloride(CPC) and the turibidity was measured by using ultraviolet-visible spectroscopy at 680nm.The linearity between the concentration of ?-PGA and its absorbance,the stability,repeatability and recovery of the method were studied.Through the reaction of ?-PGA with CPC,a homogeneous turbid solution was formed.The turbid solution was stable in 3h under proper pH value and ion strength,the absorbance of the solution at 680nm had a good linear relationshi Pwith the concentration of ?-PGA in the range 12.5~50?g/ml(R2=0.9939).The recovery was within the range of 86%~99.75%(n=5).The relative standard division of the method for determining ?-PGA at the concentrations of 5,10 and 40?g/ml were 0.14%,0.23%和0.025% repeatability.The turbidmetric method has advantages of convenience,simplicity and good repeatability and can be used to control the quality of ?-PGA and its products.