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 lg/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.