The first example of application of nanosized polystyrene‐based cation exchanger (NSCE) with sulfo groups as a dynamic coating of capillary walls was demonstrated. The conditions of dynamic coating formation were optimized and ensured the long‐term stability of the coating. Capillary‐to‐capillary and day‐to‐day repeatabilities were 4% and 3%, correspondingly. The NSCE coating stability at various pH and influence of pH on the EOF mobility were investigated. The developed NSCE‐modified coated capillaries provided improved resolution (Rs = 0.9–3.2 for catecholamines and Rs = 1.7–2.8 for amino acids) and efficiencies (330–520 ×103 t.p./m) of basic analytes, which are 1.5 times higher compared to untreated capillary. The optimized conditions were as follows: 50 mM phosphate buffer solution at pH 2.2 with 5 μM NSCE. The effect of the NSCE concentration in BGE on the electrophoretic mobilities of the analytes was investigated. The various online concentration techniques were tested in order to decrease the LODs. The simultaneous application of NSCE capillaries and field‐amplified sample stacking provided the lowest LODs of catecholamines and amino acids and allowed to determine these analytes in human urine.
Поступила в редакцию 9 января 2017 г., после доработки -14 февраля 2017 г.Работа посвящена выявлению возможностей высокоосновного наноанионита на основе ани-онита типа АВ-17 в качестве модификатора фонового электролита в капиллярном электрофорезе (КЭ) для эффективного и селективного разделения неорганических анионов. Выявлено влияние концентрации наноионита в составе фонового электролита на величину и знак электроосмотиче-ского потока (ЭОП), а также эффективность и факторы разрешения при электрофоретическом раз-делении неорганических анионов. Впервые установлено, что добавка высокоосновного наноанио-нита в фоновый электролит в концентрации, превышающей 0.01 мМ по функциональным группам, приводит к обращению электроосмотического потока. Это свидетельствует о динамической моди-фикации стенок кварцевого капилляра и приводит к росту эффективности и селективности разде-ления неорганических анионов по сравнению с результатами, получаемыми с традиционным катион-ным детергентом цетилтриметиламмоний бромидом (ЦТАБ). Предложен вариант одновременного электрофоретического разделения восьми неорганических анионов с использованием высокоос-новного анионита. Выявлены возможности различных вариантов внутрикапиллярного концентри-рования: стэкинга с усилением поля и электростэкинга. Разработанный вариант реализован при электрофоретическом определении неорганических анионов в моче.Ключевые слова: капиллярный электрофорез, неорганические анионы, наноанионит, online концентрирование. 7/9 Universitetskaya nab., St. Petersburg, 199034, Russian Federatin *Corresponding author: Darya V. Dzema, E-mail: dasha.dzema@gmail.com Submitted 09 January 2017, received in revised form 14 February 2017 In this study, the possibilities of using the highly basic nano-sized anionite based on the anionite AB-17 as a modifier of the background electrolyte (BGE) in the capillary electrophoresis (CE) for the separation of inorganic anions was investigated. The influence of the concentration of nano-sized anionite in BGE on the velocity and direction of EOF as well as on the efficiency (N, t.p.) and peaks resolution (R) of inorganic anions was determined. It was established that the addition of the highly basic nano-sized anionite to the BGE (with the concentration of functional groups of nano-sized anionite more than 0.01 mM) leads to the reversal of the EOF. This indicates the dynamic modification of the silica capillary walls by the particles of nano-sized anionites and leads to the better efficiency (up to 600*10 3 t.p.) and increased resolution of inorganic anions compared to BGE containing conventional cationic surfactant -CTAB. Various on-line
Saint-Petersburg State University, Institute of Chemistry
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