A molecularly imprinted micro-nano fiber optic sensing platform for ultrasensitive detection of perfluorooctane sulfonate

To address the limitations of conventional methods in the rapid detection of sudden environmental contamination events, a molecularly imprinted micro-nano fiber optic sensor was developed for the sensitive detection of perfluorooctane sulfonate (PFOS). The sensing mechanism relies on selective recognition enabled by molecular imprinting, whereas the enhanced sensitivity arises from strong evanescent field interactions in the tapered micro-nano fiber region. Under optimized conditions, the proposed sensing platform exhibits a high detection sensitivity of 1.4977 nm/(ng/L), and a low limit of detection (LOD) of 0.24 ng/L, which is well below the guideline limits of 4 ng/L for PFOS in drinking water established by the United States, European countries, and the World Health Organization. Selectivity studies indicate that the length of the perfluorinated carbon chain plays a critical role in molecular recognition and sensing performance. Furthermore, real-sample analysis demonstrates that the proposed sensor enables reliable PFOS detection in lake water and complex biological matrices, including egg and milk samples. These results highlight the strong potential of the molecularly imprinted micro-nano optic fiber sensor for applications in environmental monitoring and biomonitoring.