A bisspiropyran fluorescent probe for the selective and rapid detection of cyanide anion in liqueurs

Abstract

Cyanide anion (CN⁻) in diet may cause serious health risks, and hence it requires a sensitive, selective, and rapid detection method, particularly in on-site tests. In this study, a novel bisspiropyran (SP1) fluorescent probe has been designed and prepared for the selective and rapid detection of CN⁻ in liqueurs. Containing two spiropyran units linked by an alkyl chain, the developed SP1 probe exhibited excellent photoluminescence properties and a specific fluorescence response towards CN⁻. Moreover, the sensing mechanism of SP1 to CN⁻ was discussed in detail. Under the optimized analysis conditions, irradiated at 320 nm for 4 min after mixing with CN⁻ and detection at 440 nm, a SP1 probe-based fluorescence method was established for CN⁻ quantitation with a response range of 1.0–50.0 μmol L⁻¹ (2.6 × 10⁻²–1.3 mg L⁻¹), and the limit of detection was 0.21 μmol L⁻¹ (5.5 × 10⁻³ mg L⁻¹). Furthermore, this SP1 probe-based fluorescence method was applied to CN⁻ detection in liqueurs, and the accuracy was proved by the satisfied recoveries of 91.5–102.5% with relative standard deviations less than 5.5% and the low relative error of 5.0% with the results using the standard ion chromatography method. This selective and rapid CN⁻ detection method has a potential application in on-site tests of food safety.