Simple determination of Sudan dyes in fruit juice and spices by microfunnel-filter-based emulsification microextraction followed by high performance liquid chromatography

In this work, a rapid method termed as microfunnel-filter-based emulsification microextraction is coupled with high performance liquid chromatography for a simple determination of the banned Sudan dyes (I, II, and III) in fruit juice, spice, and water samples. According to the method, in order to speed-up the extraction and concentration of the target analytes, a micro-volume of a low-density organic solvent (1-octanol) is dispersed into an aqueous sample solution (45 mL), and a simple separation of the extractant phase is obtained using a syringe filter and microfunnel. The method provides a low-toxic extraction, it is centrifuge-less, and the extraction process is totally performed in a few minutes. The influencing factors including the type of organic solvent, number of extraction cycles, pH of the sample solution, and volume of the extraction solvent are investigated to achieve the optimal conditions. A good linearity (in the range of 0.7–1000 ng mL−1 (R2 > 0.995)) and a low limit of detection (in the range of 0.2-0.5 ng mL−1) are obtained, the extraction recovery is in the range of 94-107%, and the developed method provides a high enrichment factor (in the range of 294-354).