The invention relates to a preparation method of a fluorescent
molecular probe for detecting
sulfite ions through naked eyes and
fluorescence ratio as well as the application of the fluorescent
molecular probe in detecting
sulfite ions. The fluorescent
molecular probe is prepared by condensing 4-hydroxy naphthalimide serving as
raw material and acetylpropionic acid in refluent
methylene dichloride. The synthesis is simple and convenient, and the
reaction conditions are mild. The probe molecule provided by the invention has higher sensitivity, stable
fluorescence performance, higher synthesis yield and good selectivity, and furthermore, the response range of the probe is 0-1500 mu m, the
detection limit is 6 mu m; the detection range is wide, the lower
detection limit is low, and the probe is suitable for
naked eye detection. Meanwhile, the florescence-ratio detection is adopted to avoid errors caused by exciting
light intensity, probe concentration and environment factors of an off-on type probe which detects ions only depending on the change of
fluorescence intensity and the probe disclosed by the invention is not influenced by anions such as F<->, Cl<->, Br<->, I<->, HPO4<2->, SO4<2->, NO<3->, AcO<->, ClO<4->, N<3-> and HCO<3->. Even interfering ions exist, the probe has very good response to
sulfite ions. Therefore, the fluorescent molecular probe has practical application value in the fields of
biochemistry, environmental science and the like.