As flavonoids show pharmacological activity, in the present investigation, an economical
and efficient method for their trace determination was developed. In this context, the interfacial
behavior of three flavonoids, 3-hydroxyflavone (3HF), morin and hesperidin (Hesp) was studied
on the hanging mercury dropping electrode (HMDE) by phase sensitive ac voltammetry and cyclic
voltammetry (CV). The investigated flavonoids were strongly adsorbed which is the prerequisite
step for applying the cathodic adsorption stripping voltammetric determination of some flavonoids.
Based on the adsorption character of investigated flavonoids onto the surface of the HMDE,
validated, simple, fast and sensitive square-wave cathodic adsorptive stripping voltammetric
(SWCASV) procedure for the quantification of the flavonoids under investigation in bulk form
and in biological fluids was described. Moreover, controlled adsorptive accumulation of the Cu(II)
complex of flavonoids was also achieved to assay indirect determination of 3HF, morin and Hesp
via the reduction of the formed complex. Operational and solution conditions for the quantitative
ultra-trace determination of the investigated flavonoids were optimized in the absence and presence
of Cu(II). Limits of detection of 4.4 × 10-9, 7.19 × 10-9 and 7.54 × 10-9 mol L-1 3HF, morin and
Hesp in bulk form were achieved using SWCASV, respectively.