Highly sensitive and selective colorimetric and fluorescent dual-readout assay for the analysis of spermine, spermidine and cysteine.

Fluorescent cuprous iodide (CuI)-based coordination polymers (CuI-CPs) were widely used in the sensor field for high selectivity and sensitivity. Here, a new CuI-CP fluorescent probe was fabricated for the detection of spermine, spermidine and cysteine with dual-mode, which was capable of both convenient colorimetric analysis and ratiometric fluorescent detection. The fluorescence of CuI-CP solution was quenched and the solution changed from white to purple upon addition of spermine or spermidine, while the solution changed from white to yellow for cysteine. This probe exhibited selective, sensitive, rapid and linear response to spermine, spermidine and cysteine with a limit of detection of 0.57, 1.06 and 1.18 μM, respectively. Furthermore, cellulose acetate was used as the matrix to fabricate intelligent fluorescent film for real-time and visual monitoring the freshness of pork samples based on distinct fluorescence changes under UV light. This work realized a rapid, efficient, and profitable method for visually evaluating food quality. This work developed a real-time and visual detection of the freshness of food. [Display omitted] • A novel dual-mode probe was designed for detection spermine, spermidine and cysteine. • The probe exhibits high sensitivity with LOD of 0.57, 0.98 and 1.18 μM, respectively. • The probe was used as colorimetric analysis and ratiometric fluorescent detection. • An intelligent fluorescent film for real-time, visual monitoring freshness of pork. [ABSTRACT FROM AUTHOR]