Room-temperature phosphorescence based on chitosan carbon dots for trace water detection in organic solvents and anti-counterfeiting application

Trace water is known to be an impurity in organic solvents, having an adverse effect on the chemical reaction or environmental safety. Developing a green, facile and non-toxic method for detecting trace water in various organic solvents is still a challenge. Distinct form conventional fluorescent probes, room-temperature phos-phorescence (RTP) test paper (TP) has aroused wide concern owing to its characteristic optical performance, including long afterglow and non-background interference. Herein, we fabricated a new kind of RTP-TP on the basis of chitosan carbon dots (CDs). The anchoring effect of polyvinyl alcohol (PVA) promoted the restriction of vibration/rotation and hindered the non-irradiative quenching of CDs by forming intermolecular hydrogen bonds. However, water molecules could interrupt these hydrogen bonds and therefore the RTP phenomenon would be disappeared. Further, the RTP-TP was used to detect trace water in various organic solvents with high efficiency, excellent stability, and reliability. In addition, the CDs-PVA solution can be also used as anti-counterfeiting ink via various printing methods.

Automated summary

A novel room-temperature phosphorescence test paper was developed based on chitosan carbon dots, offering efficient, stable, and reliable detection of trace water in various organic solvents, and can also be used as anti-counterfeiting ink through various printing methods.