设计合成了一种以耐尔蓝为母体的Hg2+光学探针分子1-苯甲酰-3-{2-[9-(乙氨基)-10-甲基-9H-苯并[α]苯酚-5-胺基]乙基}硫脲盐酸盐(NBET).在pH=7.4的Tris-HCl缓冲液中,探针分子最大吸收波长为640 nm,此时溶液为淡蓝色;加入汞离子可以诱导探针分子在640 nm处的吸收降低,并在556 nm处产生新的吸收峰,溶液变为浅紫色,而其它金属离子的加入未引起显著变化,基于此可对水溶液中的痕量Hg2+进行裸眼识别.荧光光谱显示,汞离子可以特异性地猝灭探针分子在660 nm处的荧光发射.该探针分子的灵敏度、选择性及荧光量子产率高,激发/发射波长长,可以实现水溶液中0.005μmol/L Hg2+的荧光检测.
A sensitive and selective Nile blue-based optical sensor 1-benzoyl-3-{2-[9-(ethylamino)-10-methyl-9H-benzo[α]phenoxazin-5-ylamino]ethyl}thiourea hydrochloride(NBET) in aqueous solution for Hg2+ was synthesized.The maximum absorption peak of the probe molecule appeared at 640 nm,and decreased upon the addition of Hg2+ in 0.05 mol/L Tris-HCl buffer solution at pH=7.4,a new peak of absorption at 556 nm was observed.The color of the solution changed from light blue to light purple.There was neglectable change upon the addition of other metal ions.Fluorescence monitoring revealed a fluorescence quenching of the probe's characteristic emission at 660 nm upon the addition of Hg2+.The probe possessed the advantages of near-infrared excitation and emission and high fluorescence quantum yield in aqueous solution and offer an opportunity to detect Hg2+ by a "naked-eye" manner.Limit of detection of fluorescence spectral for Hg2+ was found to be 0.005 μmol/L in aqueous solution.