中国生物工程杂志

A turbid solution was formed through the reaction between γ-PGA and cetylpyridinium chloride (CPC) and the turibidity was measured by using ultraviolet-visible spectroscopy at 680nm The linearity between the concentration of γ-PGA and its absorbance ,the stability ,repeatability and recovery of the method were studied. Through the reaction of γ-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 relationship with the concentration of γ-PGA in the range 12.5-50ug/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 γ-PGA at the concentrations of 5 、10和 40ug/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 γ-PGA and its products.