Determination of 11 Kinds of Synthetic Pigments in Gelatin Capsules by HPLC

To establish a method for the determination of 11 kinds of synthetic pigments in gelatin capsules by high performance liquid chromatography(HPLC). After being hydrolyzed by papain for 30 min at 60℃,the sample was separated by CAPCELL PAK C₁₈(4.6 mm×250 mm,5 μm)using methanol-acetonitrile(1:1)and 15 mmol/L ammonium acetate as mobile phase by gradient elution. The target compounds were detected with diode array detector at the wavelength 450(tartrazine,quinoline yellow),520(new red,amaranth,ponceau 4R,sunset yellow,allura red,carmoisine and erythrosine)and 620 nm(indigotine,brilliant blue). The results showed that 11 kinds of synthetic pigments had a good linear relationship in the range of 0~100 μg/mL,the correlation coefficient was over 0.999,the method limit of detection was 0.3~2.5 mg/kg,the average recovery rate was 79.1%~119.3%. The method could be operated easily and rapidly with high sensitivity and good separation,and it could be used for simultaneous determination of 11 kinds of synthetic pigments and suitable for the analysis of synthetic pigments in gelatin capsules.