Abstract: Ternary system of Morin-Al(Ⅲ)-Nucleic acids was studied by spectrophotometry. At pH 3.25 Britton-Robinson medium, morin has the absorption peaks at 250, 300 and 350nm. When Al³⁺ was added, the absorption of morin at 350nm decreased and a new absorption peak at 419nm appeared. Adding of nucleic acids to the morin-Al(Ⅲ) binary system leads to decrease of the absorption at 350nm and great increase at 419nm. There is an isochromatic point at 370nm. The increase of absorbance at 419nm is proportional to the amount of nucleic acids added within certain concentration range. Based on this, a new sensitive nucleic acids analysis method is established. The linear ranges of ct DNA, fs DNA and y RNA are 0.71～35.4，0.64～25.6 and 0.94～28.4μg/mL, respectively.

Key words: morin, Al(Ⅲ), nucleic acid, spectrophotometry

摘要： 用分光光度法研究了桑色素-铝离子-核酸三元体系。在pH 3.25的Britton-Robinson介质中, 桑色素在250，300和350nm处有吸收峰。铝离子的加入使桑色素350nm处的吸收峰下降, 在419nm处出现桑色素-铝络合物的吸收峰。再往桑色素-铝离子二元体系中加入核糖核酸或脱氧核糖核酸, 则进一步引起桑色素350nm吸收峰的降低，419nm处的吸收大大加强, 同时在370nm处有一等色点。419nm处吸光度的增加值与加入的核酸量在一定范围内成正比, 基于此建立了在较宽范围内测定核酸的方法。其线性范围分别为：ρ(ct DNA), 0.71～35.4μg/mL；ρ(fs DNA), 0.64～25.6μg/mL；ρ(y RNA), 0.94～28.4μg/mL。

关键词: 桑色素, 铝离子, 核酸, 分光光度法