A test strip constructed by molecular imprinting for ratiometric fluorescence with ultra-low limit of detection for selective monitoring of Sudan I in chili powder.

Tian Shi, Tong Liu, Jinyuan Zhang, Da Cai, Yueli Zhang

Mikrochimica acta 2023 Jun 19

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An up-conversion molecularly imprinted ratiometric fluorescent probe with a monodisperse nuclear-satellite structure and its test strip are designed which can avoid fluorescent background interference to detect Sudan I in chili powder highly selective and sensitive. The detection mechanism is based on the selective recognition of Sudan I by imprinted cavities on the surface of ratiometric fluorescent probe and the inner filter effect between Sudan I molecules and the emission of up-conversion materials (NaYF4:Yb,Tm). Under optimized experimental conditions, the response of fluorescent ratio signals (F475/F645) of this test strip show a good linear relationship in the range 0.02-50 μM Sudan I. The limits of detection and quantitation are as low as 6 nM and 20 nM, respectively. Sudan I is selectively detected in the presence of fivefold higher concentrations of interfering substances (imprinting factor up to 4.4). Detection of Sudan I in chili powder samples show ultra-low LOD (44.7 ng/g), satisfactory recoveries (94.99-105.5%) and low relative standard deviation (≤ 2.0%). This research offers a reliable strategy and promising scheme for highly selective and sensitive detection of illegal additives in complex food matrix via an up-conversion molecularly imprinted ratiometric fluorescent test strip. © 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Austria, part of Springer Nature.

Citation

Tian Shi, Tong Liu, Jinyuan Zhang, Da Cai, Yueli Zhang. A test strip constructed by molecular imprinting for ratiometric fluorescence with ultra-low limit of detection for selective monitoring of Sudan I in chili powder. Mikrochimica acta. 2023 Jun 19;190(7):263