铝试剂的共振散射光谱研究

Resonance Light Scattering of Aurintricarboxylic Acid

研究了铝试剂 (ATA)的共振散射光谱、吸收光谱和荧光光谱。在pH3 7～ 1 1 0的溶液中 ,ATA的共振光散射 (RLS)信号很弱 ;当pH <3 7时 ,RLS随pH值减小而增强 ,pH 2 7时达到最大。RLS信号增强的原因是ATA由带负电荷的型体转变为中性分子并聚集形成超分子聚合体。RLS光谱图中 2 60和 340nm出现两个散射峰 ,30 0nm处为一峰谷 ,而在吸收光谱图中 30 0nm处为一吸收峰 ,由此可知ATA的RLS光谱与其吸收光谱有关 ,RLS信号强度随波长的变化不符合瑞利散射定律。ATA的荧光激发光谱和发射光谱不重叠 ,说明RLS光谱中没有共振荧光成分。在实验条件一定时 ,RLS强度与ATA浓度有关 ,但不是严格的线性关系。

Resonance light scattering (RLS), absorption and fluorescence spectra of aurintricarboxylic acid (ATA) were studied. In solutions with pH 3.7 to pH 11.0, the RLS signal was very weak, but increased sharply with a decrease in pH when pH < 3.7 and reached a maximum at pH 2.7. This enhancement effect of RLS occurred because the negative charged species of ATA were transformed into neutral,molecules when pH decreased, and the neutral molecules assembled into supermolecular aggregates. Two peaks at 260 nm and 340 nm, respectively, and a valley at 300 nm, appeared in the RLS spectrum, whereas an absorption peak appeared at 300nm in the absorption spectrum. This spectral feature reveals that the RLS spectrum was related to the absorption spectrum of ATA. The change in RLS intensity with the wavelength was not accordant with Rayleigh scattering law. The fluorescence excitation and emission spectra of ATA do not overlap, so resonance fluorescence was not involved in the RLS spectrum. Under a given set of experimental conditions, the RLS intensity increased with the increase in ATA concentration, which, however, was not a strictly linear relationship.