Interference-free simultaneous determination of Sudan dyes in chili foods using solid phase extraction coupled with HPLC–DAD

A simple, rapid, inexpensive and robust solid phase extraction (SPE) cleanup method coupled with high performance liquid chromatography–diode array detector (HPLC–DAD) for the determination of four Sudan dyes in chili products was developed. The interference substances were removed completely by normal SPE-Alumina N, resulting in a clean and interference-free baseline. Without the use of expensive LCMS/MS instrument the low levels of Sudan dyes were identified and quantified in chili foods with good precision and recovery. Depending on the Sudan dyes involved, the limit of determination (LOD) and limit of quantification (LOQ) were in the range of 4.1–5.8 and 13.2–19.1 μg/kg, respectively. The recovery, repeatability and reproducibility varied from 93.2% to 103%, from 0.3% to 4.4%, and from 0.6% to 4.9%, respectively. This method is suitable for the routine analysis of Sudan dyes for the common factory laboratory due to its sensitivity, simplicity, convenience and low-cost.