Analysis of Sudan I in Food by QuEChERS Combined with Ultrasound-assisted Dispersive Liquid-liquid Microextraction with Solidification of Floating Organic Drop (UADLLME-SFO) Prior to HPLC-PAD

A convenient and environmentally friendly method was developed for extraction and enrich of Sudan I from tomato sauce and chilli products. The method is based on an ultrasound-assisted dispersive liquid-liquid microextraction with solidification of floating organic drop (UADLLME-SFO) after a preliminary QuEChERS procedure, which was followed by high performance liquid chromatography with photodiode array detection (HPLC-PAD). The several parameters involved in the UADLLME-SFO step was optimized. The optimal variables obtained were 30 mu L of 1-dodecanol as the extraction solvent, 1.0 mL of acetone as disperse solvent, ultrasonic irritation for 15 min, and no salt addition. Under the optimum conditions, the limit of detection for Sudan I was as low as 1.5 mu g kg(-1). The recoveries obtained was between 79% and 92% (RSD, 4.8% - 7.1%, n = 7). The proposed method was successfully applied to the determination of Sudan I in four kinds of real samples.