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The polymerisable fluorescent monomer, allyl carbazole, was synthesized from carbazole and characterized using FT-IR spectra, 1H NMR and fluorescence spectra. Using allyl carbazole as fluorescent dye, carboxyl polystyrene fluoresent microspheres, polyacrylamide fluorescent microspheres and polystyrene fluoresent microspheres with sulfonic groups with narrow particle size were prepared by dispersion polymerization. These fluorescent microspheres were characterized by SEM, fluorescence microscopy, FT-IR spectroscopy, the conductivity, fluorescence spectrophotometry and UV-vis spectrometer. The results indicated that the three kinds of fluorescent microspheres with good dispersion and stability and high blue fluorescence intensity were obtained. And carboxyl groups, sulfonic groups and amino groups were successfully introduced on the surface, whose contents were approximately 45, 90 and 60 μmol g−1, respectively. Furthermore, the characteristics of allyl carbazole should be maintained in the fluorescent microspheres, the difference of the spectra between fluorescent microspheres and allyl carbazole in ethanol and toluene were also proved.

Derivatives of oxazine dyes were synthesized on mulitigram scales via efficient synthetic strategies. One practical route was selected to prepare compounds 6, 9 and 10, especially water-soluble compound 6 was obtained in better yield than reported, and compound 10 was insoluble in aqueous media in absence of phenolic-OH. Compounds 3 and 9 were found to be clear pH-dependent between pH = 4.0 and 10.0, and could be used as acid-base indicators to measure intracellular pH. Compounds 6, 9, 10 all have carboxylic acid functionalities, which could be activated and used to conjugate the dyes to biomolecules. In addition, compounds 6 and 9 with good solubility in aqueous media were used to develop a simple, quick, safe, highly sensitive staining method to detect PHAs-producing bacteria on heat-fixed smears, which was confirmed by fluorescence images of PHAs granules of bacteria.

To prepare nitrogen doped carbon dots (NCDs) with excellent luminescence efficiency, a facile hydrothermal method was developed using cabbage juice as the carbon source and poly ethylene polyamine (PP) as the nitrogen source. Then, as-prepared NCDs were grafted onto calcium alginate to produce calcium alginate film (CA-NCDs), and the CA-NCDs were used as a fluorescent probe. The significant quenching effect of Fe3+ was established. The ratio of fluorescence intensity (F/F0) of the CA-NCDs had a linear relationship with the concentration of Fe3+ within the range of 0 to 48 μM (R2 was 0.9947) and the detection limit was 1.4 nM. In addition, the recovery of spiked samples ranged from 98.6% to 103.1%. Most importantly, the amino-functionalized CA-NCD fluorescent probe can be successfully applied for the detection of trace Fe3+ in water samples.