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Ionic liquid/anionic surfactant aqueous two-phase system was developed and applied for the extraction of Sudan I–IV. High-performance liquid chromatography was applied to the determination of the analytes. The aqueous two-phase system (ATPS) was formed in the present of C 4 [MIM]BF 4 , sodium dodecyl benzene sulphonate and (NH 4 ) 2 SO 4 . The parameters affecting the extraction efficiency, such as volume of ionic liquid, amount of sodium dodecyl benzene sulphonate, ionic strength, pH value of system, extraction time and temperature were investigated. The limits of detection for Sudan I, II, III and IV were 5.45, 4.66, 3.68, 4.20 μg kg −1 , respectively. When the present method was applied to the analysis of candy samples, the recoveries of the analytes ranged from 82.3% to 112.1% and relative standard deviations were lower than 7.41%. [ABSTRACT FROM AUTHOR]

Butyrylcholinesterase (BChE), as a member of the cholinesterase family, is widely expressed in various tissues and cell types. Abnormal activity levels of BChE in organ systems or cells are usually associated with diseases. Therefore, developing effective methods for monitoring the distribution and activity of BChE in vivo is significant for exploring the physiological effects of BChE in organisms and improving prophylaxis, diagnosis or therapy of diseases. In this study, a dihydroxanthene-derived fluorescent probe CHQ-B with near-infrared (NIR) excitation and emission maxima was developed for visualizing endogenous BChE in vivo. This probe exhibits superior selectivity and sensitivity towards BChE, as well as low cytotoxicity and good biocompatibility to biosamples. Furthermore, efficient and robust fluorescence imaging of the distribution and activity of BChE in diabetic mouse models confirmed the high expression of BChE induced by diabetes. Results of experiments demonstrated that CHQ-B is a promising fluorescence imaging tool for exploring butyrylcholinesterase expression in organisms during researches of relationships between BChE expression and various diseases. [Display omitted] • A novel fluorescent probe with both excitation and emission maxima at NIR region. • High sensitivity (LOD = 0.032 U/L) and selectivity to BChE. • Visualization of the expression variation of BChE in diabetic models. [ABSTRACT FROM AUTHOR]