A smartphone-based ratiometric fluorescent sensing system for on-site detection of pyrethroids by using blue-green dual-emission carbon dots.

Exploring the high-performance fluorescence strategy for on-site monitoring of pyrethroids is of great significance to the protection of the ecological environment and human health. Aiming at attaining precise onsite analysis, blue-green dual-emission carbon dots (CDs) were used as well-resolved optosensing centers, and an innovative ratiometric fluorescence core-shell nanosphere was constructed using molecular imprinting in this study. The ratiometric fluorescent signal of the CDs was used by the nanospheres to realize on-site quantitative detection of pyrethroids with excellent selectivity. The detection range of this ratiometric sensing platform was 1-150 μg/L and the limit of detection (LOD) was obtained, as low as 0.048 μg/L. Importantly, the core-shell nanospheres exhibited fluorescence changes on exposure to pyrethroids under UV irradiation. A smartphone application was used to output the color channel values of the captured images. The smartphone-based ratiometric sensing system was used for the quantitative detection of pyrethroid with a sensitive LOD of 0.61 μg/L, which could meet the needs of real analytical samples. This sensing platform showed great application potential for the on-site detection of pesticide residues in agriculture food and pollution control in resource-limited environments.