Stelmach Emilia, Maksymiuk Krzysztof, Michalska Agata
Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland.
Talanta. 2016 Oct 1;159:248-254. doi: 10.1016/j.talanta.2016.06.024. Epub 2016 Jun 15.
Copolymeric acrylate microspheres were prepared from hexyl acrylate using different amounts of methacrylic acid, resulting in a series of microspheres of gradually changing properties. The distribution of carboxyl groups - between surface and bulk of microspheres was evaluated. Bulk reactive carboxyl groups were determined using reverse coulometric titration with H(+) ions, following hydroxide ions have been generated and allowed to react with microspheres in the first step. It was found that the number of reactive carboxyl groups available in copolymeric microspheres is lower compared to number of methacrylic acid units used for polymerization process. Moreover, there is correlation between the number of groups introduced and found to be reactive in microspheres. On the other hand, the number of surface reactive groups was proportional to the number of groups introduced in course of polymerization. Thus, the surface reactive groups can be used as reagent, in novel heterogeneous microtitration procedure, in which a constant number of microspheres of different carboxyl groups contents is introduced to the sample to react with the analyte. The applicability of novel proposed method was tested on the example of Ni(2+) determination.
使用不同量的甲基丙烯酸由丙烯酸己酯制备共聚物丙烯酸酯微球，得到一系列性质逐渐变化的微球。评估了羧基在微球表面和本体之间的分布。在第一步中产生氢氧根离子并使其与微球反应后，使用H(+)离子的反向库仑滴定法测定本体反应性羧基。发现共聚物微球中可用的反应性羧基数量比用于聚合过程的甲基丙烯酸单元数量少。此外，引入的基团数量与微球中发现具有反应性的基团数量之间存在相关性。另一方面，表面反应性基团的数量与聚合过程中引入的基团数量成正比。因此，表面反应性基团可以用作试剂，用于新型非均相微滴定程序，其中将不同羧基含量的恒定数量的微球引入样品中以与分析物反应。以Ni(2+)测定为例测试了新提出方法的适用性。
