Determination of digoxin by in-capillary derivatisation based on the formation of o-tolyl- and 2-naphtyl- anionic boronate esters in combination to large volume sample stacking-capillary electrophoresis is proposed. Derivatisation reaction is performed at basic pH values to obtain compounds with charge and a chromophore group during the stacking process. After the stacking, the species were separated and detected at 225 nm using p-nitrophenol as internal standard. Stacking and derivatisation parameters such as pre-concentration time, preconcentration voltage and injection time (relation between the analyte and the derivatisation agent) were evaluated using a Box-Behnken design. In the optimal conditions, the proposed method exhibits a linear range 1.08 – 50.00 µM with a limit of detection of 0.36 µM, additionally an adequate repeatability and reproducibility obtained (%RSD ≤ 5.0%) is achieved. The methodology was validated by comparison to a HPLC UV-Vis established methodology and was successfully applied to digoxin determination in pharmaceutical tablets and blood serum samples, showing a positive performance for these matrices.

You have access to this article

Please wait while we load your content... Something went wrong. Try again?