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Hg2+比率荧光探针

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Hg²⁺比率荧光探针(RN). 在甲醇/乙腈/4-羟基哌嗪乙磺酸缓冲溶液(pH=7.2, 体积比8:1:1)中, RN对Hg²⁺具有比色和比率荧光双重响应. 加入Hg²⁺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Hg²⁺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Hg²⁺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Hg²⁺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.

Highly Selective Ratiometric Fluorescent Probe for Hg2+Based on Fluorescence Resonance Energy Transfer Between 1,8-Naphthalimide and Rhodamine B†

A ratiometric fluorescent probe(RN) was developed based on rhodamine B and 1,8-naphthalimide which were linked together by an amido linkage. In CH3 OH/ CH3 CN/ HEPES buffer solution(pH=7. 2), free RN showed absorption maximum at 412 nm. The presence of Hg2+ 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 Hg2+. Significantly, the probe RN gave rise to a ratiometric fluorescent response to Hg2+. Upon the addition of Hg2+, a significant fluorescence enhancement at 580 nm and meanwhile the gradual disappearance of the emis-sion at 540 nm were observed, which were ascribed to the fluorescence resonance energy transfer(FRET) from 1,8-naphthalimide 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 for naked-eye detection of Hg2+. The ratiometric fluorescence signal for Hg2+ was not affected by other coexisting mental ions.