Labetalol (I) [36894-69 6] and methyldopa (II) 1555-30-61 were determined in pharmaceuticals by performing voltammetry at platinum test electrode vs Ag/AgCl reference eloctrode in sodium hydroxide, potassium hydroxide, hydrochloric acid and acetic acid systems. These compounds followed Ilkovic equation linearly upto 5 x 10(-4) Mole/dm3 with 98% reproducibility based on their oxidation potentials. Labetalol showed higher sensitivity in potassium hydroxide and sodium hydroxide, while methyldopa showed higher sensitivity in acetic acid system. Gold did not work when used as a test electrode. This method can be preferred to the reported methods for the determination of these drugs due to its better detection limits, reproducibility of the results, and less interference from dissolved oxygen.


S MUNIBULLAH HUSSAINI ,S AZHAR ALI ,ABDUL SAMAD ,