Sensitive determination of Sudan dyes in foodstuffs by Mn-ZnS quantum dots

Abstract A novel luminescence sensing system has been designed for Sudan dyes detection based on the quenched fluorescence (FL) of oleic acid-functionalized Mn–ZnS quantum dots (QDs). The Sudan dyes could quench the fluorescence signal of Mn–ZnS QDs due to the so-called inner filter effect. Herein, it was demonstrated that this facile methodology could offer a rapid, reliable and selective detection of Sudan dyes, and the detection limits of Sudan I, II, III, and IV were 24.6, 32.7, 2.1, and 3.2 ng/mL, respectively. In this work, Sudan dyes were mainly detected in hot chili sauce, sausage, egg and tomato sauce, and Sudan I was chosen as spiked substance owning to its wide use as a coloring matter among Sudan dyes in many industrial and daily products. Furthermore, the recoveries of Sudan I from the standard fortified blank samples were in a range of 93.0–107.0%, and the relative standard deviations (RSDs) were lower than 2.8% ( n  = 3).