A novel ratiometric fluorescent probe based on dual-emission carbon dots for highly sensitive detection of salicylic acid.

In this study, a novel ratiometric fluorescence probe based on dual-emission carbon dots (CDs) for the sensitive detection of salicylic acid (SA) was constructed for the first time. The dual-emission CDs were synthesized by simple hydrothermal method using tartaric acid (TA) and m-phenylenediamine (mPD) as raw materials. In the presence of SA, the fluorescence intensity of CDs was enhanced at 499 nm, but remained basically unchanged at 439 nm. This phenomenon is caused by the intermolecular hydrogen bond interactions. The concentrations of SA had an excellent linear relationship with CDs' fluorescence intensity ratio (F/F) in a range of 1 ∼ 120 and 120 ∼ 240 μM with low detection limits of 0.68 and 1.05 μM. The established ratiometric fluorescent probe is economical, simple and green, and can be used for the effective detection of SA. In addition, the proposed ratiometric fluorescent probe was successfully used to monitor SA in facial mask and toning lotion samples with a satisfactory recovery of 99.7-106.7 %. The results show that the constructed fluorescent probe based on dual-emission CDs has a great potential for the rapid and sensitive analysis of SA in actual samples.