Efficient electrochemical defluorination of fluorinated drugs in aqueous medium with product monitoring by ion selective electrode/mass spectrometry methods

The electrochemical defluorination of fluorinated pharmaceuticals, including widely used antibiotics levofloxacin and ciprofloxacin, as well as ripasudil, a glaucoma treatment drug, was investigated in aqueous media within the hydrogen evolution potential range. Efficient cleavage of C–F bonds was achieved under mild electroreduction conditions and confirmed by mass spectrometry and potentiometric determination of released fluoride ions using a fluoride ion-selective electrode. The method exhibited high selectivity toward a dominant defluorinated product under the applied experimental conditions. The proposed reaction pathway is based on literature reports and suggests the involvement of electrogenerated reactive hydrogen species in weakening the C–F bond, thereby facilitating its subsequent electrochemical cleavage at carbon-based electrodes without the use of metal catalysts. The method was validated using tap and river water samples, demonstrating its robustness and applicability to realistic aqueous matrices. In terms of application, the approach provides an electrochemical platform for time-resolved monitoring of defluorination efficiency and degradation products, contributing to the development of sustainable analytical technologies for pollution control and pharmaceutical waste management. • Hydrogen-boosted electrochemical defluorination enables highly efficient and selective C–F bond cleavage. • A single defluorinated product is obtained electrochemically, unlike multiple by-products from photocatalysis. • Electrogenerated hydrogen species act as strong reductants, allowing complete fluorine removal under mild conditions without toxic catalysts. • High defluorination efficiency in natural water samples demonstrates the method’s environmental applicability. • Real-time monitoring of fluoride ion release via ion-selective electrodes supports process control and analytical reliability.