Simultaneous determination of Sudan dyes and carotenoids in red pepper and tomato products by HPLC

To simultaneously detect Sudan dyes and carotenoids in red pepper and tomato products, high-performance liquid chromatography (HPLC) methods with photodiode-array detection are developed and validated. The methods include the use of end-capped and nonend-capped adsorbents with a gradient elution system starting with water containing methanol. Water content of 9% in the starting mobile phase is found to be necessary to ensure sufficient separation of Sudan dyes and to avoid overlapping or interference with the carotenoids of considerable content. The data of the validation reveal the accuracy and precision of the developed methods. A limit of Sudan dyes detection of 1-5 μg/g in red pepper or tomato sauce could be approached. The methods provide excellent separation of the carotenoids from the unsaponified extracts of red pepper and the tomato products.