Separation of pharmaceutical bases from neutral and acidic components by capillary electrochromatography

Capillary electrochromatography with a silica column with a dynamically modified cationic surfactant

“…For example, poor peak shape of strong basic compounds was observed on the silica based ODS stationary phase [3]. A way to resolve the problem is the addition of competing base to the mobile phase [5,6], but special instrumentation with pressurization of both the capillary ends is required in order to avoid The influence of CTAB concentration and methanol content on the capacity factors of alkylbenzenes was also investigated in this study. The results are shown in Figs.…”

“…It was also found that the peak heating. Therefore a pressure of 8 bar [5] or 10 bar tailing of basic compounds can be effectively elimi- [6] was applied to both sides of capillary to avoid nated in this mode because the surfactant has more bubble formation by utilization of those mobile affinity to silanol than common basic compounds. phases, which requires a more complex instrument and cannot be performed on most of the standard capillary electrophoresis instrument.…”

“…Several relary (100 mm I.D.3365 mm O.D.) was obtained from searchers [5,[7][8][9][10] have reported a number of sepaYongnian Optic Fiber Plant (Hebei, China). Five mm rations on these packings.…”

Reversed‐phase capillary electrochromatography for the simultaneous determination of acetylsalicylic acid, paracetamol, and caffeine in analgesic tablets

“…Solutes are separated according to their partitioning coefficient between the two phases and, when charged, their electrophoretic mobility should also be considered. A strong electroosmotic flow (EOF) is necessary in order to speed up the CEC analysis and this can be easily obtained by using classical reversed-phase stationary phases where free silanol groups are present [25,26]. As in CE, the EOF has a nearly flat flow velocity profile with reduced dispersion compared to LC, leading to a high efficiency [23].…”

“…Pharmaceuticals (and their impurities) are often basic, and, therefore, the application of CEC to pharmaceutical analysis can be often problematic. However, the addition of a competing amine to the mobile phase at low pH, has been proposed to improve the separation of basic substances by reversed-phase CEC [25,[37][38][39].…”