Facile preparation of lignin-based material for fluorescent detection of pyrrole

The utilization of rich lignin to synthesize fluorescent probes with low toxicity, good biocompatibility, low cost, and high fluorescence has attracted significant attention due to its great potential value in sensor applications. To achieve accurate and sensitive detection of amines, a lignin-based intelligent fluorescent material (Lum-MDI-Lignin) with high fluorescence is designed for ultrasensitive determination of pyrrole (PYR) and a variety of amines by constructing responsive functional groups (-C = O and –NH). This preparation strategy enabled Lum-MDI-Lignin to achieve detection limits of 0.036 μM in fluorescence mode and 0.011 μM in UV–Vis mode, respectively which was significantly superior when compared to only lignin and luminol. Moreover, the material demonstrated a remarkable specificity even in the presence of 10 common aliphatic and aromatic amines. The fluorescence was significantly quenched after adding 0.289 µM of different amines which indicate that intramolecular electron transfer process was ceased as a result of interaction of the sensor with various amines. However, interesting results were obtained after adding pyrrole where fluorescence was enhanced. Additionally, the material is fabricated into fluorescent inks and realized security printing applications. This design provides a universal strategy to promote the active utilization of biomass resources such as lignin and offers a new “fluorescence turn on” approach for ultra-sensitive detection of pyrrole.