金刚石–有机聚合物杂化离子色谱固定相的研制及应用

Synthetic diamond combines mechanical stability, chemical inertness and absence of shrinking or swelling in the presence of inorganic or organic solvents. Therefore, it could be applied as the potential substrate of chromatographic stationary phase in ultra performance ion chromatography. However, direct utilization of synthetic diamond as the substrate of ion chromatographic stationary phase is still not available, due to the difficulty of modifying the inert diamond surface and severe chromatographic band broadening causing by irregular and nonuniform diamond shape. To overcome the shortages of diamond as the chromatographic stationary phase substrate and that commercial polymer–based stationary phase is fragile at condition of ultra–high pressure, an approach to prepare novel diamond–organic polymer hybrid stationary phases is proposed by cladding or embedding. With the advantages of diamond, mechanical strength of the hybrid substrate would be improved. After the functional modification of the hybrid substrate, high column efficiency is available by the employment of spherical stationary phase. The novel hybrid stationary phase could be operated at a wide pH range (~pH 0–14) as the traditional polymer–based stationary phase, and especially under ultra-high pressure as the silica–based stationary phases, making ultra performance ion chromatography possible with short analytic time and high efficient separation. Additionally, the investigation of chromatographic parameters of novel hybrid stationary phase under ultra–high pressure would be performed. Finally, the optimized hybrid stationary phase and separation conditions would be applied to the analysis of samples with complex matrix or multi components.

人造金刚石具有机械强度大，化学稳定性强，有机溶剂兼容性好等优点，可作为超高效离子色谱固定相的潜在基质。但金刚石的惰性表面不易于直接功能化修饰，并且颗粒的不规则或不均匀严重影响色谱分离柱效，因此不适合直接作为色谱固定相基质。本项目为克服金刚石作为色谱固定相基质存在的不足及市售有机聚合物基质固定相不耐超高压的缺点，拟通过包覆、掺杂等方式制备球形金刚石–有机聚合物杂化基质。利用金刚石独特的物理化学特性，提高基质微球的机械强度；并且球形基质的使用有利于提高色谱固定相的柱效；最后对基质微球进行功能化修饰，研制开发超高效离子色谱固定相。该固定相不仅具有传统有机聚合物基质固定相耐酸碱性强的优点，同时兼具硅胶基质固定相柱效高、耐超高压的特点，从而实现目标离子在超高压条件下的快速、高效分离。此外，将探索金刚石–有机聚合物杂化基质固定相在超高压条件下的色谱性能变化，并应用于复杂基质样品及多组分样品的分析检测。

固定相在色谱仪器中有着举足轻重的作用，它直接影响物质的分离。虽然分析物的分离效果受流动相，流速，温度等因素的影响，但对其影响最大的还是固定相自身的性质。因而在液相色谱中，开发分离效果好，分析速度快并且能适应各种环境的新型固定相依旧是未来发展的一个重要趋势。本项目利用人造金刚石具有机械强度大，化学稳定性强，有机溶剂兼容性好等优点，制备具有机械性能优异的金刚石–有机聚合物杂化基质。.利用浓硫酸和浓硝酸的混合酸氧化纳米金刚石，增加了其表面羟基，环氧基和羧基等基团浓度，提高了纳米金刚石的亲水性。用BDDE和甲胺对氧化纳米金刚石进行季铵化，使其表面带有季铵基团同时提高了它的分散性。采用红外光谱仪、热重分析仪、X射线光电子能谱分析仪以及XRD对纳米金刚石进行了表征，结果表明纳米金刚石表面成功键合了羟基及有机聚合物层，且金刚石的晶型未发生改变。.通过比较悬浮聚合法，乳液聚合法和种子溶胀法等方法合成的纳米金刚石-聚合物复合型填料的形貌特征，选择以种子聚合法合成聚苯乙烯-二乙烯基苯-氧化纳米金刚石，制备的填料经扫描电镜，透射电镜，氮气吸附脱附等方法进行表征，并对不同掺杂量的聚苯乙烯-二乙烯基苯-氧化纳米金刚石进行了色谱性能和机械性能测试。最后以掺杂0.15 g氧化纳米金刚石的聚苯乙烯-二乙烯基苯作为基质合成了一种阴离子交换剂。.以季铵化纳米金刚石为胶体通过静电作用和磺化的微球附聚得到附聚型阴离子交换剂，再以该阴离子交换剂为基质，用1,4-丁二醇二缩水甘油醚 (BDDE) 和甲胺 (MA) 在其表面进行接枝反应，制备的阴离子交换剂分离效果良好，稳定性高，能在pH=1～13的环境和有机溶剂中保持稳定；用1,4-丁二醇二缩水甘油醚和甲胺合成的阳离子聚电解质与磺化的聚合物微球附聚，再用1,4-丁二醇二缩水甘油醚和甲胺进行接枝反应得到的阴离子交换剂有良好的分离效果。最后对两种阴离子交换剂进行了机械稳定性和化学稳定性测试。