Gd^(3+)离子在氨基多膦酸配合物溶液中的敏化发光研究

Sensitized Fluorescence of Gd^(3+) in Aminopolyphosphonic Aicd Complex Solution

对 Gd3+离子与氨基多膦酸配体 (乙二胺四亚甲基膦酸和氨三亚甲基膦酸 )配合物溶液荧光的研究表明 ,在碱性溶液中 2种配体可使 Gd3+离子的荧光强度分别增强 9倍和 7.4倍 ,比氨基多羧酸的荧光敏化作用要强得多。其激发和发射峰分别在 2 74 nm和 310 nm,与 Gd3+水合离子相应谱峰的位置相同。表明这种荧光增强来源于氨基多膦酸配体对 Gd3+强烈的配位作用所引起的 f→ f跃迁的部分解禁。由于 Gd-氨基多膦酸配合物十分稳定 ,因此配合物溶液荧光强度基本不受其他共存阴阳离子的影响 ,在一定范围内受 p H值变化的影响也很小。

Fluorescence of Gd 3+ could be greatly enhanced in ethylenediaminetetrakis (methylphosphonic) acid (EDTP) and nitrogentri(methylphosphonic) acid (NTP) complex solutions of pH 7—11 for about 9 and 7.4 times, respectively. However the excitation and emission peaks were the same with those of Gd 3+ aquatic ion.The enhancing effect is proposed to be a consequence of strong coordination between Gd 3+ and ligands, which introduce additional uninhibition to the f→f transition of Gd 3+ . Owing to the high stability of the Gd aminophosphonic acid complex,various coexist ions or pH variation in range of 7—11 have little effect on the fluorescence intensity,which indicates these aminophosphonic acid are potential reagents for fluorometry determination of Gd 3+ ions.