Polarographic determination of N-acetyl-L-cysteine in pharmaceutical preparations.

The polarographic behaviour of N-acetyl-L-cysteine in Britton Robinson Buffer (BRB) over the whole pH range was studied. At pH 10, a well-defined anodic wave was developed. The wave was irreversible, one-electron, diffusion-controlled and partially affected by adsorption phenomenon. Adopting both direct current (DCT) and differential pulse polarographic (DPP) modes, the current concentration plot is rectilinear over the range 0.05 to 1.0 mM and 0.01 to 0.75 mM, respectively, with a minimum detection limit of 0.0005 mM using the DPP mode. The proposed method was successfully applied to the determination of N-acetyl-L-cysteine in pharmaceutical preparations. The obtained results were in a good agreement with those obtained by the official method.