用荧光光谱法研究了在铜(Ⅱ)、铅(Ⅱ)及镍(Ⅱ)存在时对苋菜红(AT)与牛血清白蛋白(BSA)结合反应的荧光光谱特性的影响。试验在pH 7.43的B-R缓冲溶液中进行,荧光测定的激发波长(λex)为280 nm和发射波长(λem)为350 nm。试验发现:① 由于与AT的结合,使BSA的内源性荧光发生猝灭现象,荧光的猝灭程序随AT的浓度增加而加强;② 上述3种离子的加入,使AT-BSA体系的荧光猝灭有不同程度的增强;③ 3种离子均能与AT竞争参与和BSA的结合,产生以生成不发光基态配合物为主的静态荧光猝灭,加强了AT对BSA的猝灭作用,但并不改变其反应的类型,在猝灭反应中同时有非辐射能量转移;④ 在3种离子中铅(Ⅱ)与BSA的结合能力更强。

Fluorophotometric study on the interation of bovine serum albumin (BSA) with amaranth (AT) in the presence of Cu(Ⅱ), Pb(Ⅱ) and Ni(Ⅱ) was made in a B-R buffer medium of pH 7.43 with λex and λem at 280 nm and 350 nm respectively. It was found that: ① due to binding with AT, quenching of intrinsic fluorescence of BSA was observed, and magnitude of the fluorescence quenching increased with increase of concentration of AT; ② upon addition of each of the 3 cations, fluorescence quenching of the reaction system of BSA-AT was enhanced at various extents; ③ each of the 3 cation take competition with AT to react with BSA to form mainly groud-state coordination complex of non-emission fluorescence, attributing to static quenching process, which enhanced the fluorescence quenching without changing the type of reaction. Non-radiative energy transfer happened to take place simultaneously with the quenching reaction, and ④ binding force of Pb(Ⅱ) with BSA hehaved to be stronger than the other 2 cations.