3D-printed electrochemical cell for both detection and degradation of venlafaxine and desvenlafaxine with boron-doped diamond electrode

• VF and DVF voltammetric responses strongly depend on BDD surface composition and pH • Nucleation side of free-standing BDD outperforms growth side for VF and DVF sensing • VF and DVF determined in spiked river water and pharmaceutical capsules • BDD growth side achieves ∼97% removal of VF and DVF via advanced oxidation • Proven integrated detect-and-degrade platform using free-standing BDD and 3D printing Venlafaxine (VF) and its active metabolite desvenlafaxine (DVF) are widely prescribed antidepressants that are only partially metabolized and excreted in significant amounts, making them clinically important analytes and environmentally relevant contaminants. In this study, a free-standing boron-doped diamond (BDD) electrode is exploited in a dual role for the electrochemical detection and degradation of VF and DVF, integrated into a custom 3D-printed dual-function electrochemical cell. The nucleation (BDD NS ) and growth (BDD GS ) sides of the BDD plate were systematically compared under different surface terminations. Oxidized BDD NS (O-BDD NS ) provided three well-resolved oxidation peaks for VF, whereas hydrogen-terminated BDD NS (H-BDD NS ) yielded a single distinct peak for DVF in 0.1 M H 2 SO 4 . Differential pulse voltammetric (DPV) methods were developed with limits of detection of 0.35 µM for VF (peak 1) and 0.34 µM for DVF and wide linear ranges in the low-to-high micromolar region. By exploiting the different surface-termination preferences and multi-peak behaviour of VF, simultaneous determination of VF and DVF was achieved. The methods showed good selectivity toward common interferents and were successfully applied to spiked river water and pharmaceutical capsules using the standard addition approach, giving recoveries close to 100%. In the 3D-printed cell, BDD GS was used for electrochemical advanced oxidation, achieving ∼97% degradation of 1 mM VF and DVF in 0.1 M H 2 SO 4 within 20 min under galvanostatic conditions, following pseudo-first-order kinetics. In situ DPV on BDD NS enabled real-time monitoring of VF decay, demonstrating an integrated detect-and-degrade platform based on BDD and additive manufacturing.