Study of the retention behaviour of barbiturates by overpressured layer chromatography using silica gel bonded with tricaprylmethylammonium chloride

Thin-layer chromatography in the analysis of narcotic and strongly acting substances (a review)

“…The separation of barbamyl, barbital, and phenobarbital on the Silufol UV-254 plates is recommendeit with a mobile phase of benzene-dioxane-25% aqueous ammonia Kovacs-Hadady [23,24] used high-pressure TLC on a Chrompress-25 system (Laboratory Instruments Co., Hungary) and successfully separated more than ten barbituric acid derivatives (including those under international control) on the Silieagel 60 F2.s4 (Merck) plates in the reversed-phase regime. The plates were impreL, nated with methanol solutions of dodecyltrimethylammonium bromide (DTMA), tricaprylmethylammonium chloride (TCMA), or a 10% paraffin solution in n-hexane.…”

“…The plates were impreL, nated with methanol solutions of dodecyltrimethylammonium bromide (DTMA), tricaprylmethylammonium chloride (TCMA), or a 10% paraffin solution in n-hexane. The recommended mobile phase represented a methanol -water 3 : 7 mixture [23,24].…”

A systematic study of the desorption of different ion-pairing reagents on reversed phase thin-layers

“…As a result of these studies the situation existing in the stationary phase before the chromatographic run have been described. Depending on the composition of the mobile phase, the chromatographic run changes the concentration of the ion-pairing reagent in the stationary phase [2][3][4][5]. Recently [6] we have reported the results for the absolute concentrations of different ion-pairing reagents (tetramethylammonium bromide, TMA; tetrabutylammonium bromide, TBA; cetyltrimethylammonium bromide, CTMA and trioctylmethylammonium chloride, TOMA) on silica gel layers, after the chromatographic run.…”

Simultaneous effect of organic modifier and physicochemical parameters of barbiturates on their retention on a narrow-bore PGC column

“…Because of their considerable importance in health care much effort has been devoted to the development and application of various chromatographic methods for the separation and quantitative determination of barbituric acid derivatives such as gas [1] and thin-layer chromatomatography [2], etc. Numerous high-performance liquid chromatographic (HPLC) techniques with high separation capacity and elevated sensitivity have also found employment in the analysis of barbiturates [3].…”