A Ti⁴⁺/Zr⁴⁺ ion immobilized sorbent was developed by starting from monodisperse-porous titania microbeads, for the isolation of nucleosides via immobilized metal affinity chromatography (IMAC). For the synthesis of IMAC sorbent, the monodisperse-porous titania microbeads were coated with a polydopamine (PDA) layer. PDA coated titania microbeads were then interacted with TiCl₄ or ZrOCl₂ solution for the immobilization of Ti⁴⁺ or Zr⁴⁺ ions onto the PDA layer. Five nucleosides (adenosine, uridine, cytidine, thymidine and guanosine) were individually adsorbed onto Ti⁴⁺ or Zr⁴⁺ immobilized titania microbeads in aqueous buffer in a pH range of 4–9. The desorption of nucleosides was performed in an aqueous formic acid solution. The nucleoside isolation performance of Ti⁴⁺ immobilized sorbent was also compared with Zr⁴⁺ immobilized sorbent, PDA coated titania and bare titania microbeads. The highest equilibrium adsorptions and the highest desorption yields were obtained with Ti⁴⁺ immobilized sorbent for all nucleosides. It was demonstrated that pH 7 was found as the most appropriate for the adsorption of all nucleosides onto Ti⁴⁺ immobilized sorbent, which was also close to the physiological pH of urine. The highest equilibrium adsorption was observed with adenosine as 12.67 mg adenosine/g Ti⁴⁺ immobilized sorbent. Almost quantitative desorption yields were achieved with all nucleosides adsorbed in a wide range of pH onto Ti⁴⁺ immobilized sorbent. With respect to the similar sorbents developed previously, we believe that the proposed sorbent is a promising candidate for being a stationary phase particularly for the construction of micro-column based IMAC systems used in the continuous isolation of nucleosides.

中文翻译：

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Ti 4+ / Zr 4+固定化聚多巴胺涂层单分散多孔二氧化钛微珠的核苷分离性能

从单分散多孔二氧化钛微珠开始，开发了Ti ⁴⁺ / Zr ⁴⁺离子固定吸附剂，用于通过固定金属亲和色谱法（IMAC）分离核苷。对于IMAC吸附剂的合成，将单分散多孔二氧化钛微珠涂有聚多巴胺（PDA）层。然后将PDA涂覆的二氧化钛微珠与TiCl ₄或ZrOCl ₂溶液相互作用，以将Ti ⁴⁺或Zr ⁴⁺离子固定在PDA层上。五个核苷（腺苷，尿苷，胞苷，胸苷和鸟苷）分别吸附在Ti ⁴⁺或Zr ^4+上在pH范围为4–9的水性缓冲液中固定二氧化钛微珠。核苷的解吸在甲酸水溶液中进行。还比较了固定有Ti ^4+的吸附剂与Zr ⁴⁺固定的吸附剂，PDA包覆的二氧化钛和裸露的二氧化钛微珠的核苷分离性能。Ti ⁴⁺固定吸附剂对所有核苷均具有最高的平衡吸附和最高的脱附产率。结果表明，pH 7最适合将所有核苷吸附到固定有Ti ^4+的吸附剂上，这也接近尿液的生理pH。腺苷的最高平衡吸附为12.67 mg腺苷/ g Ti ⁴⁺固定的吸附剂。在宽pH范围内将所有核苷吸附到固定化Ti ^4+的吸附剂上，几乎可以实现定量的解吸产率。对于以前开发的类似吸附剂，我们认为拟议的吸附剂是固定相的有希望的候选者，特别是用于连续分离核苷的基于微柱的IMAC系统的构建。