Selective Recognition Of Microelement Based On Novel Fluorescent Probe

Fluorescent conjugated polymer probes have been widely applied to many fields, such as organic molecules, metal ions and biological molecules detection, due to its sensitivity, real time response and designability. Two kinds of fluorescent probes based on conjugated polymer were designed and used to quantitative detect metal ions (iron ions) and biological small molecules (fructose), respectively.Firstly, a novel strategy for identification and detection of iron ion in aqueous solution was developted. A fluorescent poly(m-aminobenzesulfonic acid) was formed by m-aminobenzenesulfonic acid as functional monomers, ammonium persulfate as initiator, iron ions as catalyst. The fluorescence intensity of the present system was related to the concentration of iron ion. The mechanism of the reaction was investigated by1H NMR, FT-IR, UV-vis, free radical scavenger, and changing species of initiators. The factors such as initiator concentration, monomer concentration, reaction temperature and reaction time were also optimized. Under the optimum conditions, linear range and detection limit of iron ion were obtained. The practical application of the method was demonstrated by detection of iron ions in drinking water and human serum, respectively. The results showed that iron ions could activate ammonium persulfate, and sulfate radical played a major role in the process of polymerization, the catalytic activity of Fe2+was better than that of Fe3+. The system showed wide linear ranges and low detection limits for iron ion:For Fe2+, linear range was divided into two parts (5.0×10-10-1.0×10-7mol/L,1.0×10-7-1.0×10-5mol/L), the detection limit was2.56×10-11mol/L; For Fe3+, linear range and the detection limit was1.0×10-7-1.0×10-5mol/L and2.34×10-10mol/L, respectively. The correlation coefficients were all above0.99. The novel strategy had high selectivity and was used successfully to detect the iron ion in drink water and human serum.Secondly,(aminophenylboronic acid-m-phenylenediamine) polymer was synthesized by free radical polymerization reaction of aminophenylboronic acid and m-phenylenediamine in aqueous solution with ammonium persulfate as initiator. The polymer was characterized by UV-vis and fluorescence spectra, respectively. The mechanism of determination, linear range, detection limit and specificity were investigated. The results showed that the boron hydroxyl of polymer can interact with the cis-adjacent diol of fructose. Fluorescence intensity of the polymer decreased with the increasing concentration of fructose in the range of10-10-2mol/L, and with a detection limit of10-8mol/L. The feasibility of the resulted material for detection of fructose has also been demonstrated by real sample.