Abstract Many dye molecules form different aggregation states in aqueous solution under different concentrations. Acridine orange (AO) is a cationic fluorescence dye and is commonly used in DNA analyses. Most measurements for light absorption and fluorescence emission of dyes sorbed on solid matrix reported in literature were performed in clay-dye suspension. Rarely, it was evaluated in solid state. In this study, the fluorescence effect of AO, after being sorbed on 2:1 layered clay minerals montmorillonite (MT), rectorite (RT), and illite (IT), was evaluated in terms of contributions by different forms of AO (monomer, dimer, H- and J-aggregates). As the amounts of AO sorbed increased, the proportion of absorption spectra made by monomer and dimer decreased, while that made by of H- and J-aggregates increased. In sorbed state, the absorbance of AO monomer and dimer was obvious while that attributed to H- and J-aggregates was higher in comparison to that in AO solution. At AO loading of 30 μmol/g on MT and 24 μmol/g on RT and IT, fluorescence emission reached maximum intensity. While the majority of the fluorescence was attributed to monomer and dimer, an unknown peak at 580–590 nm was resolved in the fluorescence spectra. Due to its red shift, it was attributed to J-aggregates on the surface of the minerals. The contribution by H-aggregates was observed in absorption spectra, but not in fluorescence spectra, which was speculated that the blue shift caused by H-aggregates overlapped with the excitation wavelength of 490 nm. The 2:1 clays could serve as a substrate for optimal dye sorption to achieve maximum fluorescence emission effect and practical applications of such dye-clay composites in powder form could be further explored.

中文翻译：

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吖啶橙吸附在 2:1 层状粘土矿物上的增强荧光效应

摘要 许多染料分子在不同浓度的水溶液中形成不同的聚集态。吖啶橙 (AO) 是一种阳离子荧光染料，常用于 DNA 分析。文献中报道的吸附在固体基质上的染料的光吸收和荧光发射的大多数测量是在粘土染料悬浮液中进行的。很少，它以固态进行评估。在这项研究中，AO 被吸附在 2:1 层状粘土矿物蒙脱石 (MT)、蒙脱石 (RT) 和伊利石 (IT) 上后的荧光效应，根据不同形式的 AO（单体、二聚体、H-和J-聚集体）。随着AO吸附量的增加，单体和二聚体吸收光谱的比例下降，而H-和J-聚集体的吸收光谱比例增加。在吸附状态下，AO单体和二聚体的吸光度明显，而归因于H-和J-聚集体的吸光度高于AO溶液中的吸光度。在 MT 上 30 μmol/g AO 和 RT 和 IT 上 24 μmol/g AO 负载下，荧光发射达到最大强度。虽然大部分荧光归因于单体和二聚体，但在荧光光谱中解析了 580-590 nm 处的未知峰。由于它的红移，它归因于矿物表面的J-聚集体。在吸收光谱中观察到 H-聚集体的贡献，但在荧光光谱中没有观察到，这推测由 H-聚集体引起的蓝移与 490 nm 的激发波长重叠。2：