This contribution deals with the development and application of voltammetric and amperometric (HPLC-ED) methods for the determination of selected biologically active organic compounds, namely 5-amino-6-nitroquinoline (5-A6-NQ), 1,2-diaminoanthraquinone (1,2-DAA), and propyl gallate (PG) on bare or chemically modified carbon paste electrodes in either batch (voltammetry) or flow (amperometry) arrangements.