| With the rapid growth of population in the world and the quick development of modern industry and agriculture,the problem of water pollution caused by toxic anion and cation has become more and more serious.Some of them such as Cu2+and CN-would accumulate in organisms,which is great harmful for deactiving the basic biological function of biological organs to results in series of diseases.Accordingly,it is desired for us to develop some effecient sensing materials to monitor these toxic ions quickly,effectively and conveniently.In this paper,four water-soluable organic chromophores with huge?-conjugated systems will be identified and prepared according to the special physicochemical property properties of these toxic ions respectively.After the structures and spectral performances were characterized in detail,the spectral responses to some toxic ionsin the environment were investigated as followings:?1?After brief reviews on organic Schiff base and azo chromophores were presented,the applications of UV-vis and fluorescence spectroscopy in common toxic ions were summarized,which expressed low water-solubility and selectivity in practice.?2?Anovelkindofwater-solubleSchiffbase,N-2?-benzothiazole-2-hydroxy-naphthalimide was synthesized by condensation reaction between 2-aminobenzothiazole and 2-hydroxy-1-nayl formaldehyde.After its structure was confirmed by 1H NMR,its fluorescence spectrum and UV-Vis absorption spectrum were studied especially in detail.The results show that when excited at?ex=345 nm,the target compound exhibits different fluorescent responses to CN-and Ac-with no obvious interference in the presence of other coexisting anions,and the detection limit are 5.4×10-5 mol/L and 2.8×10-5 mol/L respectively.Under the optimized conditions(cdye=4.0×10-6 mol/L,VH2O/VDMSO/VCH3CN=1/48/1),there is a linear relationship between F440/F0 and c-CN in the range of 2.0?6.0×10-5 mol/L and a linear regression equation of F440/F0=-3.9+0.283 c-CN?R2=0.9936?.For Ac-,the linear relationship between F540/F1 and c-Ac was 5.0?12.25×10-6 mol/L with a linear regression equation of F540/F1=-64.346+8.006 c-Ac?R2=0.9960?under the optimized conditions of cdye=4.0×10-6 mol/L,VH2O/VDMSO/VCH3CN=1/48/1,cHCl=1.5×10-5 mol/L.The stoichiometric ratio of 1:1 between N-2?-benzothiazole-2-hydroxy-naphthalimide and CN-or Ac-was confirmed by Job'plot and 1H NMR.The proposed probe was successfully applied for detection of CN-and Ac-in some real aqueous and vegetable juice samples,the recovery range was80.20%?84.10%and 101.50%?106.50%,the R.S.D of the CN-were less than2.07%,and the R.S.D of the Ac-were less than 0.60%.?3?Anotherwater-solublepolyhydroxylchromophore,bis-2,4,6-trihydroxy-N,N?-2?,6?-diimide pyridine,was synthesized using2,6-diaminopyridine and 2,4,6-trihydroxybenzaldehyde as raw matweials.After its structure was characterized by 1H NMR and UV-vis absorption spectra,it was noted that the present bis-2,4,6-trihydroxy-N,N?-2?,6?-diimide pyridine possesses a good selective response to CN-with 35.0%water content,the detection limit was2.09×10-7 mol/L.Under the optimized conditions,there was an excellent linear relationship between c-CN and A517 in the range of 2?280×10-7 mol/L,which A517 is the absorption intensity at 517 nm.The linear regression equation for CN-detection was A517=0.2338+0.0157 c-CN?R2=0.9947?with a 1:1 stoichiometric ratio.Importantly,the proposed probe was applied to detect CN-in real environmental water and vegetable samples with satisfactory results,the recovery was between84.50%?99.30%,and the relative standard deviation?R.S.D.?were less than 0.69%.?4?In this part,a water-soluble multidentate ligand,bis-2,4,6-trihydroxy N,N?-3?,5?-diimide benzoic acid,was designed and synthesized using3,5-diaminobenzoic acid and 2,4,6-trihydroxy benzaldehyde as raw materials,whose structure was characterized and confirmed by 1H NMR and UV-vis spectral analyses.It was noted that there was a selective colorimetric response for bis-2,4,6-trihydroxy N,N?-3?,5?-diimide benzoic acid to heavy metal Cu2+,and the detection limit was2.06×10-6 mol/L.Upon addition of Cu2+,the maximum absorption peak of bis-2,4,6-trihydroxy N,N?-3?,5?-diimide benzoic acid was blue shift with a gradual decrease in the absorption intensity.Under the optimized conditions,there was an excellent linear relationship between Amax and cCu2+in the range of 4?128×10-7 mol/L with a linear regression equation of Amax=-0.0013 cCu2++0.6404?R2=0.9899?.Also,the present colorimetric probe was successfully applied to the detection of Cu2+in some real environmental aqueous and vegetable samples,the recovery was between99.05%?106.95%,and the R.S.D were less than 3.31%.?5?A multiple water-soluble azo dye with a D-?-A-?-D conjugated system,3,5-dis-?2,4,6-tri-hydroxy phenyl azo?benzoic acid?THPBA?,was identified and developed using phloroglucinol as the electron-donating group,benzoic acid as the electron-accepting group and azo double bond as the bridging group.After the structure was confirmed by IR and 1H NMR,its UV-Vis absorption spectral property,especially the spectral response to pH was investigated carefully.The results expressed that the proposed THPBA,combining carboxyl group,azo and multi-hydroxyl group,possessed excellent UV-vis absorption spectrum(?max from2.794×104 to 2.115×104 L·mol-1·cm-1)with changing pH and solvents.Especially in DMF-H2O?v/v=1:9?,there was a nice spectral response for THPBA to pH in the linear range of 5.2?7.5,which was successfully applied to detect pH values in some commercial aqueous samples and fruit juices with some quite satisfied results. |
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