| A simple analytical method, based on the Thin Layer Chromatography (TLC) and Cloud Point Extraction(CPE) of high peformance liquid chromatography (HPLC), are developed for the determination of Sudan dyes (I, II) in chilli powder, chilli oil and food additive samples. In this paper, designing to set up a more convenient and accurate way to detect the Sudan dyes from food used regularly, we collected Sudan dyes from food using the methods of the Thin Layer Chromatography (TLC) and Cloud Point Extraction(CPE) as the former step, and detected the Sudan dyes utilizing the method of liquid chromatography (LC).Eventually, Thin Layer Chromatography-High Performance Liquid Chromatography determination of Sudan Red in the food indicated that with n-hexane as the extractant to achieve Sudan dyes from samples, n-hexane and ethyl acetate (100:0.5, V/V) as developing solvent with the Self-made silica gel G plate efficiency will obtain higher workpiece ratio with the least time. Parameters related to extraction of Sudan dyes was also optimized. After dissolving and diluting with n-hexane, the samples of Sudan red was detected under the optimal conditions that column temperature was30℃, flow velocity were1.0ml/min, the injection volume were10μl, the detection wavelength was230nm and mobile phase were acetonitrile and water(V/V=90:10). Then we can obtain their linear regression rquation. Sudan I, II linear regression equation, respectively, were Y=1151.04X+14.167and Y=1187.95X+33.958; correlation coefficient R=0.9978and R=0.9991; linear in the range of0.32-0.64μg/ml; food in Sudan I recoveries between94.59%and98.05%, while food in Sudan II between89.69%and94.75%. The measurement of relative standard deviation are less than1%.With the satisfying results, the method is suitable for detection of Sudan dyes in food. Cloud Point Extraction-High Performance Liquid Chromatography determination of Sudan Red in the food indicated that with nonionic surfactant Triton X-114as the extractant to achieve Sudan dyes from samples, Influence of the extraction of the parameters and variable for optimum condition that0.3%Triton X-114(W/V),2%Na2CO3(W/V), temperature control at45degrees C, time setting for20min; Then will handle the good sample in the experimental conditions that column temperature was30℃, flow velocity was1.0ml/min, the injection volume were10μl, the detection wavelength was230nm and mobile phase were acetonitrile and water(V/V=90:10). Then we can obtain their linear regression rquation. Sudan I, II linear regression equation, respectively, were Y=1258.74X+13.333and Y=1208.78X+77.292; correlation coefficient R=0.9993and R=0.9995; linear in the range of0.32-0.64μg/ml; food in Sudan I recoveries between91.23%and97.46%, while food in Sudan II between91.96%and92.05%. The measurement of relative standard deviation are less than1%. This shows that the method of detection Sudan red accuracy and precision are quite good. |
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