高灵敏度席夫碱镁离子荧光探针的合成及识别性能研究

A Highly Sensitive Fluorescent Probe for Detection of Magnesium Ion(Ⅱ) Based on Novel Schiff's Base

以对氨基苯甲酰肼为连接基团,分别通过氨基和酰肼基团引入丹磺酰氯和2-羟基-1-萘醛,制备了新型席夫碱(Schiff's base)类荧光探针TZ,实现了对镁离子(Mg^(2+))的高灵敏度识别。利用电喷雾质谱、紫外光谱、荧光光谱等研究了荧光探针TZ对Mg^(2+)的识别作用与机理。紫外光谱表明,单纯探针TZ在386.5 nm出现了萘醛的特征吸收峰;当探针TZ与Mg^(2+)结合后,在411 nm处出现新的吸收峰,等吸收点为400 nm。荧光光谱表明,探针TZ与Mg^(2+)结合后激发波长红移到400 nm,在发射波长468 nm处荧光强度增强10倍,量子产率为0.57。当向TZ中加入其它金属离子(Li^+、Na^+、K^+、Zn^(2+)、Ca^(2+)、Mn^(2+)、Cd^(2+)、Pb^(2+)、Ag^+等)时,荧光强度并未发生明显变化,表明TZ对Mg^(2+)具有较高的选择性。通过ESI-MS滴定和Job's plot曲线确定了TZ与Mg^(2+)的配位模式为1∶1的关系,检出限可达0.13μmol/L。

A highly sensitive fluorescent probe TZ based on a novel Schiff's base was prepared for detection of Mg2+.It was constituted by introducing dansyl chloride and 2-hydroxy-1-naphthaldehyde through amino and hydrazide groups on p-aminobenzoyl hydrazide.The recognition mechanism of the fluorescent probe TZ for Mg2+was studied by electrospray ionization mass spectrometry(ESI-MS),UV-vis and fluorescence spectra.UV-vis spectra showed that the probe TZ had a characteristic absorption peak of naphthalene aldehyde at 386.5 nm,and a new absorption peak at 411 nm was observed after coordination between TZ with Mg2+.A sharp isobestic point was obtained at 400 nm.Fluorescence spectra showed that the emission wavelength was red-shifted to 400 nm upon the addition of Mg2+into probe TZ.The fluorescence intensity was enhanced by 10 times at the emission wavelength of 468 nm and the quantum yield of 0.57 was obtained.Moreover,chemical bond energy transfer was found when 2-hydroxy-1-naphthaldehyde was coordinated with Mg2+.When the other metal ions(Li+,Na+,K+,Zn2+,Ca2+,Mn2+,Cd2+,Pb2+,Ag+,etc.)were added into TZ,no significant change of fluorescence intensity was observed.It indicated that TZ had high selectivity to Mg2+.Furthermore,the recognition of TZ to Mg2+was not interfered by other competing metal ions.ESI-MS titration and Job's plot analysis confirmed that 1:1 complexation stoichiometry between TZ and Mg2+was obtained.The lowest detection limit was up to 0.13μmol/L.