Determination of lignocaine hydrochloride by ion-pairing flow injection with piezoelectric detection

A rapid and simple method for the determination of lignocaine hydrochloride by ion-pairing flow injection analysis was developed. It is based on the formation of an ion pair between lignocaine hydrochloride and sodium dodecyl phenylsulfonate and piezoelectric detection. The calibration curve was linear between 0.01 and 2.00 mg ml-1, with a detection limit of 8 micrograms ml-1, an RSD of 0.29% (10 replicates) and a sampling frequency of 120 h-1. The proposed method was satisfactorily applied to the determination of lignocaine hydrochloride in pharmaceutical preparations.