2. Experimental part
The standards of ifosfamide (IF) and cyclophosphamide (CF) (Table 1) were purchased from Sigma–Aldrich (Steinheim, Germany). Acetonitrile (ACN) was HPLC grade, while sodium sulfate, sodium chloride, Cy5.5 NHS ester sulfate, sodium hydroxide, potassium phosphate, potassium nitrate, ammonium sulfate were obtained from POCH S.A. (Gliwice, Poland).
Structure of IF and CF molecules and the main intermediate products identified by LC–MS during electrochemical oxidation of both drugs.Parent compoundIntermediates[M+H]+tR (min)StructureIF[M+H]+ = 261tR = 14.6 min27510.72777.62797.82496.0u.i.3115.4u.i.CF [M+H]+ = 261tR = 15.7 min25911.427510.42496.9u.i3073.4u.iu.i. unidentified.tR – retention time.Full-size tableTable optionsView in workspaceDownload as CSV
2.2. Electrochemical experiments
The Total Current Efficiency (TCE) was calculated using the relation :equation(1)TCE=FV[(CODt)-(CODt+Δt)]8IΔtwhere (CODt), and (CODt+Δt) denote the chemical oxygen demand (mol O2 m−3) at time t (initial time) and t + Δt (after 4 h of electrolysis) (s), respectively; I is ribose a current (A); F is a Faraday’s constant (C mol−1); and V is a volume of electrolyte (m3).