Abstract As a cationic fluorescence dye acridine orange (AO) is commonly used in biology and biochemistry for DNA analyses. In this study the light absorption and fluorescence of AO after being sorbed on kaolinite (Kao) and halloysite (Hal) were investigated. In dilute systems with initial AO concentrations of 1 × 10−6 to 1 × 10−4 M (0.3–25 μmol/g loadings on Kao), both light absorption and fluorescence emission increased as the initial AO concentrations, thus, the amounts of AO sorbed increased. In contrast, the light absorption and fluorescence emission reached maxima at 1 × 10−5 M (3 μmol/g) for Hal. In concentrated systems with initial AO concentrations of 5 × 10−4–5 × 10−3 M (22–57 and 50–126 μmol/g AO sorption on Kao and Hal), significant fluorescence quenching was observed and the fluorescence intensity decreased as the initial AO concentrations, thus, the amounts of AO sorbed increased. The results suggested that to achieve maximal fluorescence emission, monomeric AO configuration on the solid surface is a necessity. The AO sorption was mostly attributed to cation exchange between protonated AO and exchangeable cations on Kao and Hal surfaces. As such, both cation exchange capacity and specific surface area of the minerals control the maximal fluorescence emission.

中文翻译：

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用于荧光增强的 1:1 层状粘土矿物上吖啶橙负载的优化

摘要 作为一种阳离子荧光染料，吖啶橙 (AO) 常用于生物学和生物化学中的 DNA 分析。在这项研究中，研究了 AO 吸附在高岭石 (Kao) 和埃洛石 (Hal) 上后的光吸收和荧光。在初始 AO 浓度为 1 × 10-6 至 1 × 10-4 M（花王上的负载量为 0.3-25 μmol/g）的稀释系统中，光吸收和荧光发射都随着初始 AO 浓度的增加而增加，因此， AO 吸附量增加。相比之下，Hal 的光吸收和荧光发射在 1 × 10−5 M (3 μmol/g) 时达到最大值。在初始 AO 浓度为 5 × 10-4-5 × 10-3 M（22-57 和 50-126 μmol/g AO 在 Kao 和 Hal 上的吸附）的浓缩系统中，观察到显着的荧光猝灭，荧光强度随着初始 AO 浓度的增加而降低，因此，AO 的吸附量增加。结果表明，为了获得最大的荧光发射，固体表面上的单体 AO 配置是必要的。AO 吸附主要归因于质子化 AO 与 Kao 和 Hal 表面上的可交换阳离子之间的阳离子交换。因此，矿物的阳离子交换能力和比表面积都控制着最大的荧光发射。