Signal enhancement of sensing nitroaromatics based on highly sensitive polymer dots†
A new, rapid, sensitive, selective and portable fluorescence detection method for nitroaromatics based on polymer dots (Pdots) had been successfully developed not only in aqueous media but also in the solid state with test strips. The fluorescence quenching rates were proportional to the concentrations of 2,4,6-trinitrophenol (TNP) in the range of 0.2–20.0 μg mL−1 and p-nitrophenol (PNP) in the range of 0.05–6.0 μg mL−1, when Pdots were used as ratiometric fluorescent sensors in aqueous solution. The 3σ limit of detection of PNP reached 18.8 ng mL−1. Compared with polymer-based detection for nitroaromatics in the organic phase, the signal enhancement effect was initially found when Pdots were used to detect nitroaromatics in the aqueous phase. The mechanism of the interaction between Pdots and nitroaromatics was revealed as an electron transfer phenomenon from the electron-rich chromophoric probe to the electron deficient nitroaromatics. The results indicated that Pdots-based detection was particularly suitable for on-site qualitative detection and quantitative analysis of nitroaromatics.