Abstract: A test strip method was used to detect three synthetic colorants commonly used in soft drinks. Under the optimal conditions, the entire detection procedure was completed within 10 min, and the limits of detection (LODs) of three synthetic food colorants (SFCs), namely, Ponceau 4R (E124), Tartrazine (E102), and Sunset Yellow (E110), were 0.4, 0.3, and 0.4 mg/L, respectively. The proposed method was compared with thin-layer chromatography and high-performance liquid chromatography. The results of validation with 14 commercial samples indicated the reliability and sensitivity of the strip test method to the presence of the three SFCs in soft drinks. This study indicated that the polyamide film-based test strip exhibited the potential to monitor illegal or improper addition of SFCs.

Key words: synthetic colorants, polyamide, rapid detection, soft drink