Ion‐exchange vs reversed‐phase chromatography for separation and determination of basic psychotropic drugs

Abstract

Ion exchange chromatography, an alternative to reversed-phase (RP) chromatography, is described in this paper. We aimed to obtain optimal conditions for the separation of basic drugs because silica-based RP stationary phases show silanol effect and make the analysis of basic analytes hardly possible. The retention, separation selectivity, symmetry of peaks and system efficiency were examined in different eluent systems containing different types of buffers at acidic pH and with the addition of organic modifiers: methanol and acetonitrile. The obtained results reveal a large influence of the salt cation used for buffer preparation and the type of organic modifier on the retention behavior of the analytes. These results were also compared with those obtained on an XBridge C18 column. The obtained results demonstrated that SCX stationary phases can be successfully used as alternatives to C18 stationary phases in the separation of basic compounds. The most selective and efficient chromatographic systems were applied for the quantification of some psychotropic drugs in fortified human serum samples.

Lipophilicity of oils and fats estimated by TLC

“…The alkaloids are compounds with basic properties, which makes them difficult analytes in chromatographic analysis mainly because of strong interactions between their cationic forms and surface‐active groups. These interactions cause widening of spots, poor separation efficiency, and spot asymmetry . In our case, a strong tailing effect could be observed when the mobile phases consisted of methanol and water and consequently, in order to avoid this problem, the pH of the mobile phase has been adjusted to a value of 9.6 by ammonium solution addition, which plays the role of an ionization suppressor.…”

Влияние Природы Ионных Жидкостей На Сорбцию Бензимидазола И Некоторых Его Производных Из Водно-Ацетонитрильных Растворов На Октадецилсиликагеле

“…Возможным решением этих проблем могут стать ионные жидкости (ИЖ), которые, благодаря своей двойственной природе, позволяют поддерживать ряд важных для хроматографии межмолекулярных взаимодействий как с поверхностью сорбента, так и с аналитами [9], что делает их перспективными добавками в ОФ ВЭЖХ [10]. Анализируя современную литературу можно найти большое количество статей, посвященных применению различных ИЖ в качестве модификатора подвижной фазы при анализе и разделении биологически активных соединений, лекарственных препаратов, белков и даже взрывчатых соединений методом ВЭЖХ [5,6,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29]. Использование ИЖ в ОФ ВЭЖХ анализе позволяет регулировать времена удерживания биологически активных соединений при их одновременном содержании в пробе [11], не влияя при этом на порядок выхода соединений [12].…”

Total content determination for the effective fraction of the alkaloids in Dicranostigma leptopodum (Maxim.) Fedde by HPLC and ultraviolet-visible spectrophotometry

“…[19][20][21] When alkaloids are analyzed by HPLC methods, broadening and tailing are the main problems that need to be addressed. [22][23][24] In our previous study, the alkaloids of DLF were achieved by baseline separation, but the peak tailing still inuenced the quantitative determination of alkaloids in DLF. 4 Recently, it was reported that mobile phase additives could be successfully used to solve the problem of broadening and tailing.…”