Determination of Pigments in Beverage by Ultraviolet Spectrophotometry

A method for simultaneous determination of two pigments in beverage are developed by Ultraviolet spectrophotometry.Tartrazine and ponceau 4R in beverage is determinated by this method.The results show that maximum absorption wavelengths are 424 nm and 507 nm respectively,the absorption coefficients are 32.22 L·g-1·cm-1 and 35.92 L·g-1·cm-1 respectively,the molar absorption coefficients are 1.72×104 L·mol-1·cm-1 and 2.17×104 L·mol-1·cm-1 respectively.The contents of tartrazine and ponceau 4R in beverage are 4.32×10-3 mg·mL-1 and 3.36×10-3mg·mL-1 respectively,relative standard deviations are 2.89% and 2.57% respectively,the recovery rates are 89.7% and 90.6% respectively.This method is proved to be simply and convenient and deserved to be popularized.