Electrooxidation of sulfanilamide and its voltammetric determination in pharmaceutical formulation, human urine and serum on glassy carbon electrode

For the first time,sulfanilamide(SFD)was determined in otologic solution,human urine and serum by electroanalytical techniques on glassy carbon electrode(GCE).The cyclic voltammetry(CV)experiments showed an irreversible oxidation peak at+1.06V in0.1mol/L BRBS(pH=2.0)at50mV/s.Different voltammetric scan rates(from10to250mV/s)suggested that the oxidation of SFD on the GCE was a diffusioncontrolled process.Square-wave voltammetry(SWV)method under optimized conditions showed a linear response to SFD from5.0to74.7μmol/L(R=0.999)with detection and quantification limits of0.92and3.10μmol/L,respectively.The developed SWV method showed better results for detection limit and linear range than the chronoamperometrymethod.It has been successfully applied to determine SFD concentration in pharmaceutical formulation,human urine and serum samples with recovery close to100%.