Anodic stripping voltammetric assay for the determination of prazosin at carbon paste electrodes

An anodic stripping voltammetric method for the determination of prazosin h as been developed using a modified carbon paste electrode (C-8-MCPE), givin g rise to an enhancement of preconcentration efficiency diminishing by half the accumulation time. The effects of paste composition, voltammetric para meters, supporting electrolyte and pH were studied. The process is irrevers ible and controlled by adsorption, giving rise to an oxidation peak around 1.0 V in Britton-Robinson buffer (pH 2.6). A mechanism based on the oxidati on of the amine group is postulated. A comparison was made between the dete ction limits reached on the C-8-MCPE using differential pulse (DPV) and squ are wave voltammetry (SWV) as redissolution techniques. For AdS-DPV, prazos in can be determined over the 1.0 x 10(-9) to 2.0 x 10(-8) mol L-1 range wi th a relative standard deviation of 3.65% (4.0 x 10(-9) mol L-1) and a dete ction limit of 3.2 x 10(-10) mol L-1. When AdS-SWV was used, a linear range from 1.0 x 10(-9) to 2.0 x 10(-8) mol L-1 is obtained, the relative standa rd deviation being 3.46% (4.0 x 10(-9) mol L-1) and a detection limit of 7. 7 x 10(-10) mol L-1 was reached. An AdSV-DPV procedure, to determine prazos in in urine and formulations, was proposed.