In-situ preparation of molecularly imprinted fluorescent sensing test strips for on-site detection of tyramine in vinegar

Test strips as one of micro-devices are widely concerned in the fields of point-of-care detection and in-field diagnosing. For the purpose of on-site detection of tyramine, a carbon dots-molecularly imprinted fluorescent sensing test strip with high selectivity has been successfully obtained via a rapid in-situ preparation procedure (about 2.5 h). Here, the layer composed of carbon dots-molecularly imprinted polymer (CDs-MIP) with the function of the recognition and signal transduce has been formed on the surface of the filter paper strips via the sol-gel method. The developed test strip displayed a high specificity (Imprinting factor, IF = 4.96); and its fluorescence emission was quenched linearly with the increase of tyramine concentration from 0.5 to 10.0 mg L −1 . The limit of detection (LOD) is 0.059 mg L −1 (3 σ/s ). The application potential was verified by sensing of tyramine in rice vinegar and white rice vinegar with the recoveries of 90.9-104.4% (RSD < 5.8%). Many advantages including a rapid preparation and high selectivity make the fluorescence strip suitable for on-site detection of tyramine. In addition, the preparation procedure can also be easily transferred to the preparation of the fluorescence strip toward other targets.