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Journal of Food Quality
Volume 2018 (2018), Article ID 6302345, 9 pages
Research Article

Label-Free Fluorescent Determination of Sunset Yellow in Soft Drinks Based on an Indicator-Displacement Assay

School of Chemical Science and Technology, Yunnan University, Kunming 650091, China

Correspondence should be addressed to Can-Peng Li

Received 16 June 2017; Revised 12 September 2017; Accepted 22 October 2017; Published 8 February 2018

Academic Editor: Yuxia Fan

Copyright © 2018 Shilian Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This work reported a fluorescence sensing platform for Sunset Yellow (SY) determination based on competitive host-guest interaction between cucurbit[7]uril (CB7) and signal probe/target molecules. Luteolin/epigallocatechin gallate (EGCG) and SY were selected as the probe and target molecules, respectively. When luteolin or EGCG entered the CB7 host, its fluorescence significantly improved. However, upon the presence of SY in the performed luteolin·CB7 or EGCG·CB7 complex, this led to a remarkable decrease in fluorescence. This result was due to the fact that the binding constant of CB7/SY ( M−1) was greater than that of CB7/luteolin ( M−1) or CB7/EGCG ( M−1). The fluorescence intensities of CB7/luteolin and CB7/EGCG complexes decreased linearly with increased SY concentration ranges of 0.5–50.0 and 2.0–50.0 μM. The proposed method had detection limits of 0.12 and 0.45 μM and was successfully used to determine SY samples with good recoveries ranging from 96.3% to 103.8%. This competitive mode provided a promising fluorescence assay strategy for potential applications in food safety.