Abstract
A flow-through sensor for the determination of diclofenac sodium was developed, based on retention of the analyte on a Sephadex QAE A-25 anion-exchange resin packed in a flow-cell of 1 mm of optical path length, and monitoring of its intrinsic absorbance by UV-spectrophotometry at 281 nm. Diclofenac could be determined in the concentration ranges 2.0 - 40.0, 1.0 - 22.0 and 0.5 - 14.0 µg ml-1 with RSD (%) ranging from 1.05 to 1.53 for sample volumes of 300, 600 and 1200 µl, respectively. The proposed sensor was satisfactorily applied to the rapid determination of diclofenac in commercial pharmaceutical preparations and in semi-synthetic pharmaceuticals containing diclofenac and paracetamol.
