Microwave-assisted facile synthesis of polymer dots as a fluorescent probe for detection of cobalt(II) and manganese(II).

Polymer dots (PDs) were synthesized at 200 °C for 90 min via a microwave-assisted method. The PDs were characterized by fluorescence spectroscopy, UV-vis absorbance spectra, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. The PDs display blue fluorescence under 320 nm excitation with a fluorescent quantum yield of 13.48%. The PDs show stable fluorescence against ion strength and light bleaching, especially extreme pH. Significant pH-independent behavior may relate to -OH of polyvinyl alcohol (PVA) retained on the surface of PDs. The bright fluorescence of PD solution can be distinctly quenched by cobalt ion (Co) and manganese ion (Mn) in PD solution. For Co, the linear was from 3.4 to 50.0 μmol L and 46.7 to 600.0 μmol L with the limit of detection (LOD) of 1.0 μmol L. The LOD of Mn was 0.4 μmol L in the range from 1.5 to 100.0 μmol L. Self-film-forming PDs (FPDs) were obtained via dropping PD solution on quartz glass. The bright blue fluorescence of FPDs can be obviously quenched by Co and Mn. This paper may provide an efficient and flexible approach to the application of on-site detection. Graphical abstract Graphical abstract.