The derivative adsorption chronopotentiometry of flavin adenine dinucleotide

The flavin adenine dinucleotide (FAD), leucoflavin adenine dinucleotide (FADH(2)) couple was studied by derivative adsorption chronopotentiometry al a HMDE. The theory of an EE mechanism for adsorption chronopotentiometry was developed and the semiquinone formation constant determined. Constant current stripping results at pH 7.0 were consistent with previous reports that adsorbed FAD was reduced via a stable semiquinone intermediate in two reversible one-electron transfers (EE mechanism). Potentiometric stripping analysis was also carried out in which the FAD was accumulated as FADH(2) on the HMDE at a reducing potential. The FADH(2) was subsequently oxidized by dissolved oxygen. This reaction was also found to fit the EE model.