A sensitive ratiometric fluorescent sensor based on carbon dots and CdTe quantum dots for visual detection of biogenic amines in food samples.

A novel dual-emission ratiometric fluorescent sensor for biogenic amines (BAs) was prepared by simple mixing blue fluorescent carbon dots (CDs) and yellow fluorescent CdTe quantum dots (CdTe QDs). Based on different sensitive properties of pH, CdTe QDs and CDs were used as the response signal and internal reference signal, respectively. The developed ratiometric fluorescent sensor achieved quantitative analysis of eight kinds of BAs with rapid response (30 s) and low limits of detection (1.259-5.428 μM). Furthermore, color-tunable fluorescent test strips were constructed by easily assembling CDs and CdTe QDs onto filter paper. The obtained smart label showed a distinguishable fluorescent color variation from blue to green during the corruption of shrimp samples. The smart label with advantages of convenience and rapidness provided a method for visually monitoring the freshness of food samples.