Monitoring of Selected Banned Azo Dyes in Edible Oils by High-Performance Liquid Chromatography-Photodiode Array Detector

A new simple and rapid HPLC method was described and validated for simultaneous determination of eight banned dye compounds in corn and olive oil. These dyes are namely Sudan I, II, III, and IV (SI, SII, SIII, SIV); Sudan Orange G (SOG); Sudan Red G ( SRG); Fat Brown B (FBB); and Fat Red 7B (FR7B). The oil samples were dissolved in hexane, followed by liquid-liquid extraction and enrichment with acetonitrile. Then, the samples were cleaned using a PTFE syringe filter and analyzed by high-performance liquid chromatography (HPLC) coupled with a photodiode array detector (DAD) for separation, identification, and quantification of these dyes. The chromatographic separations were carried out using an ODS column under an isocratic mode using a mixture of acetonitrile, isopropanol, and water. The method was linear for all targeted compounds over the range of 0.25–50 mg/kg. All correlation recoveries were in the range 87–106% with a precision (RSD) less than 7%. Results of the twenty samples (ten corn oil and the ten olive oil samples), collected randomly from Jordanian markets during February 2018, were lower than the detection limits for the eight compounds.