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为了探讨天然产物槲皮素作为荧光探针检测醋酸根离子的选择性和灵敏性,实验将不同种类阴离子加入到槲皮素的二甲亚砜溶液中,考查槲皮素溶液的荧光强度变化。实验发现:槲皮素的二甲亚砜溶液在500 nm处有一荧光发射峰,加入醋酸根离子时,该峰强度明显增强,而其他阴离子(Cl~-、Br~-、I~-、ClO~-_4、H_2PO~-_4)对该峰强度无明显影响,同时在Q-Ac~-中加入其他阴离子未引起荧光强度的变化。表明槲皮素对醋酸根离子具有较好的选择性;荧光滴定光谱表明槲皮素对醋酸根离子具有较高的灵敏度,且荧光滴定曲线线性关系较好(R~2=0995),线性范围为1.0×10~(-6)~8.0×10~(-6)mol/L,最低检测限为1.0×10~(-7)mol/L;通过Job曲线得到槲皮素与醋酸根离子作用的化学计量比为3∶2,稳定常数为3.11×10~4。核磁等实验表明,醋酸根离子的加入破坏或减弱了体系原有的氢键,促进了槲皮素分子内电荷转移,使槲皮素的荧光强度增强。用该方法检测了样品中微量的醋酸根离子,回收率为98.82%~100.96%,测定结果稳定。
In order to investigate the selectivity and sensitivity of the natural product quercetin as a fluorescent probe for the detection of acetate ions, different kinds of anions were added to the quercetin solution in dimethylsulfoxide (DMSO) solution to examine the change in the fluorescence intensity of the quercetin solution. The results showed that the quercetin dimethylsulfoxide solution has a fluorescence emission peak at 500 nm, and the intensity of this peak is obviously enhanced when acetate ion is added. The other anions (Cl ~ -, Br ~ -, I ~ -, ClO ~ -_4, H_2PO ~ -_4) had no significant effect on the intensity of the peak, while addition of other anions in Q-Ac ~ - did not cause any change in fluorescence intensity. The results showed that quercetin had a good selectivity for acetate ion. Fluorescence titration spectra showed that quercetin had higher sensitivity to acetate ion and the linearity of fluorescence titration curve was better (R 2 = 0995). The linear range The detection limit was 1.0 × 10 ~ (-6) mol / L and the detection limit was 1.0 × 10 ~ (-7) mol / L. The quercetin and acetate ion interaction Stoichiometry is 3: 2, and the stability constant is 3.11 × 10 ~ 4. NMR and other experiments show that the addition of acetate ion destroys or weakens the original hydrogen bonds of the system and promotes the intramolecular charge transfer of quercetin so that the fluorescence intensity of quercetin is enhanced. With this method, a trace amount of acetate ion in the sample was detected, and the recovery rate was 98.82% ~ 100.96%. The determination result was stable.