Synthesis of Melamine‐Formaldehyde Microcapsules Containing Polyfluorene for Fluorescent Detection of Picric Acid in Aqueous Medium

To detect nitroaromatic picric acid (PA) in water, polyfluorene (PF) encapsulated melamine‐formaldehyde microcapsules (PF@MFMs) were fabricated via in situ polymerizations. Because of the microcapsule structure, PF@MFMs were uniformly dispersed in water maintaining the blue fluorescence of PF in the capsules. The fluorescence intensity of PF@MFMs linearly decreased with increase in the PA concentrations with high limit of detection of 3.0 × 10 −6 M. The addition of other nitroaromatic derivatives, which had structure similar to PA, or various ions did not affect the fluorescence of PF@MFMs, showing high specificity of the microcapsules toward PA.