ZnO-based molecularly imprinted fluorescence nanoprobe for selective recognition and ratiometric quantification of pectenotoxin2 in seawater

Pectenotoxin2 (PTX2), a lipophilic marine biotoxin produced by several species of dinoflagellates, poses significant ecological risks by adversely affecting the growth and survival of fish and shellfish populations. In this study, a highly selective and sensitive ratiometric fluorescence nanoprobe was developed by molecular imprinting technology based on a photoinduced electron transfer recognition mechanism. Zinc oxide (ZnO) nanorods were employed as responsive fluorophore unites, and carbon dots (CDs) extracted from coffee as internal reference signals. Under optimum condition, increasing concentrations of PTX2 in the detection system led to a remarkable quenching of blue-emitting ZnO fluorescence signal, whereas the reference emission from green-emitting CDs remained unaffected. The constructed nanoprobe exhibited a dynamic linear response to PTX2 in the range of 44–1320 ng L −1 with a limit of detection of 13 ng L −1 . Spiked seawater samples yielded satisfactory recoveries from 95.45 % to 99.55 % with relative standard deviations below 9.30 %. Furthermore, semi-quantitative analysis was achieved by integrating a smartphone-based color recognition application, followed by naked-eye visualization under UV irradiation. The dual-emission imprinted fluorescence nanoprobe demonstrates excellent specificity, high sensitivity, and practical applicability for detection of PTX2 at trace levels in seawater with low cost and fast response.