Abstract:

Amine compounds such as benzidine and melamine are widely applied in industry, leading to inevitable residues in the environment. Therefore, it is necessary to study the extraction materials and determination methods of these amine compounds. Solid phase extraction has become a common pretreatment method in laboratories owing to its advantages of high reproducibility and low usage of organic solvents. In this paper, the microwave radiation was used to rapidly synthesize polystyrene-divinylbenzene substrate. Its surface was modified by sulfonic acid reaction to obtain mixed cation exchange (MCX) materials with reverse phase and ion exchange. Then cation exchange solid phase extraction column was prepared by these MCX materials. The obtained MCX materials presented monodisperse spherical with average diameter of 54 μm. The FTIR and XPS data showed that the synthesized MCX material had the same matrix as the commercial polymer solid phase extraction column, and all of them contained -SO₃H functional group. The MCX materials had similar cation exchange capacity with three kinds of commercial columns. The enrichment performance of the lab-made cation exchange solid phase extraction column was evaluated by using benzidine and melamine as extraction targets in river water samples. The recovery rate of benzidine was 112.7%±3.5%, and that of melamine was 102.3%±2.8%. In summary, the MCX materials can be rapidly synthesized by microwave radiation. Meanwhile, the lab-made MCX cation exchange solid phase extraction column can achieve the same extraction effect as the commercial solid phase extraction column. This research greatly saves the preparation time and reduces the detection costs.

Key words: solid phase extraction column, microwave radiation heating, mixed cation exchange materials, benzidine, melamine

摘要：

联苯胺和三聚氰胺等胺类化合物是用途宽泛的有机化工中间体，在工业上大量使用，导致其在环境中广泛残留。而联苯胺和三聚氰胺在环境中浓度低，因此研究该类有机污染物的富集萃取材料尤为必要。固相萃取技术因具有操作简单、重现性高、有机溶剂使用量少的优点成为实验室常用的前处理手段之一。采用微波辅助加热悬浮聚合法快速制备出聚苯乙烯-二乙烯基苯基质微球，并对微球表面进行修饰引入磺酸基团，制备出具有反相、离子交换一体化的固相萃取材料（MCX），最后将其压制成固相萃取柱。所制备的MCX填料呈单分散的球状形貌，平均直径约为54 μm。FTIR和XPS的数据表明微波辅助加热条件下合成的MCX填料与市售阳离子聚合物固相萃取柱的基质材料结构相同，且均含有磺酸基（-SO₃H）功能基团。将MCX填料压制成与商品柱规格一致的固相萃取柱，以河水中的联苯胺和三聚氰胺作为目标物，评价制备的MCX柱的萃取富集性能。测试结果表明，MCX填料和3种市售固相萃取柱填料具有相似的阳离子交换能力。实验结果表明，MCX填料压制的固相萃取柱对河水中联苯胺的回收率为112.7%±3.5%、三聚氰胺的回收率为102.3%±2.8%，满足监测/检测行业需求，且与市售商品柱回收率相近。不同批次的MCX填料压制的固相萃取柱在萃取水样中的目标物时，联苯胺的回收率在90%-120%、三聚氰胺的回收率在95%-105%。综上所述，利用微波辐射加热悬浮聚合法可以快速制备出强阳离子交换材料，以其为填料压制的固相萃取柱可以达到商品化阳离子固相萃取柱相同的萃取效果，且填料的合成方法重复性强，极大地节省了固相萃取填料的制备时间，提高了生产效率。

关键词: 固相萃取柱, 微波辅助加热, 阳离子交换填料, 联苯胺, 三聚氰胺