A red-emissive carbon dots-based fluorescence and colorimetric dual-mode probe for rapid and sensitive detection of perfluorooctanoic acid in environmental samples.

Perfluorooctanoic acid (PFOA) is a ubiquitous persistent organic pollutant. Hence, developing effective strategies for its fast and efficient detection in environmental samples is imperative for ecological and health safety. Herein, red-emissive carbon dots (R-CDs) were innovatively fabricated and employed to construct a novel eco-friendly fluorescence and colorimetric dual-mode probe for the effective determination of PFOA. The R-CDs were sourced from meso‑tetra(4-carboxyphenyl)porphine, ethanolamine, and oxalic acid via a facile hydrothermal method. The fluorescent intensity of the R-CDs at 652 nm and the absorbance at 415 nm decreased gradually with increasing concentration of PFOA. The experimental results demonstrated the probe exhibited good linearity across PFOA concentration ranges of 1-100 ng/mL, 100-900 ng/mL, and 1000-4000 ng/mL based on fluorescence quenching attributable to the static quenching. Additionally, the probe achieved high sensitivity with a detection limit as low as 0.0012 ng/mL. On the other hand, the probe could detect PFOA in the range of 1000-7000 ng/mL with a detection limit of 54.9 ng/mL according to colorimetric principle. This probe exhibited excellent reliability and satisfactory recoveries when analyzing the trace PFOA in actual water and soil samples. The proposed probe provided a simple, rapid, economical, and environmentally friendly platform for effectively, selectively, and sensitively detecting PFOA in environmental samples.