Application of open tubular electrochromatography for acidic and basic analytes

The separation of charged analytes by electrochromatography has been examined on porous-layer open tubular capillaries prepared using the sol gel method. An electroosmotic flow of about 2.10 x 10(-4) cm(2) V-1 s(-1) was obtained using between 10 and 30% acetonitrile in the mobile phase. Acidic diuretic drug compounds were successfully separated at high pH as were the N-alkylanilines in their basic and neutral forms. The limitation of open tubular columns was observed on separating some basic pharmaceutical drugs. These components showed severe peak tailing and were not resolved on a 20 mum i.d. porous silica layer open tubular column. Strongly acidic components could not be detected on these columns due to their higher counter electromobilities. The successful separation of neutral aryl alkyl ketones with an efficiency of 101,533 plates m(-1) for butyrophenone was an indication of the improved phase ratio on this type of open tubular columns.