基于1,8-萘酰亚胺与罗丹明B间荧光共振能量转移的高选择性Hg^(2+)比率荧光探针

Highly Selective Ratiometric Fluorescent Probe for Hg^(2+)Based on Fluorescence Resonance Energy Transfer Between 1,8-Naphthalimide and Rhodamine B

以罗丹明B与1,8-萘二甲酰亚胺反应合成了1个高选择性Hg^(2+)比率荧光探针(RN).在甲醇/乙腈/4-羟基哌嗪乙磺酸缓冲溶液(p H=7.2,体积比8∶1∶1)中,RN对Hg^(2+)具有比色和比率荧光双重响应.加入Hg^(2+)后,RN的紫外-可见光谱在约556 nm处产生强吸收,溶液由浅绿色变为橙色,其它金属离子对RN的紫外-可见光谱几乎无影响.无Hg^(2+)存在时,RN的荧光光谱在540 nm处出现萘二甲酰亚胺荧光团的特征峰;加入Hg^(2+)后,540 nm处的发射带逐渐消失,同时在580 nm附近产生强荧光,荧光颜色从绿色变为橙色.这归因于从萘酰亚胺到开环罗丹明B的荧光共振能量转移(FRET),探针RN对Hg^(2+)的比率荧光响应具有高选择性,不受其它共存金属离子的干扰.

A ratiometric fluorescent probe（RN） was developed based on rhodamine B and 1,8-naphthalimide which were linked together by an amido linkage. In CH3OH/CH3 CN/HEPES buffer solution （pH = 7.2） , free RN showed absorption maximum at 412 nm. The presence of Hg^2＋ could induce an intensive absorption at 556 nm. The change of absorption spectrum resulted in a color change from light green to orange in response to Hg^2＋. Significantly, the probe RN gave rise to a ratiometric fluorescent response to Hg^2＋. Upon the addition ot Hg^2＋ , a significant fluorescence enhancement at 580 nm and meanwhile the gradual disappearance of the emission at 540 nm were observed, which were ascribed to the fluorescence resonance energy transfer（FRET） from 1,8-naphthalinfide moiety to the ring-opened rhodamine B moiety. Accompanying the change of fluorescence spectra, the significant fluorescence color changed from green to orange occurred, which could be used tot naked-eye detection of Hg^2＋. The ratiometric fluorescence signal for Hg^2＋ was not affected by other coexisting mental ions.