A MULTICOMMUTATED FLOW SYSTEM WITH ONLINE COMPENSATION OF THE SCHLIEREN EFFECT APPLIED TO THE SPECTROPHOTOMETRIC DETERMINATION OF PINDOLOL

A continuous flow methodology for the spectrophotometric determination of pindolol in pharmaceutical preparations following complexation wit h Fe(III) is described. The reaction is carried out within a multicomm utated flow network by employing a binary sampling approach. The Schli eren effect, associated with the pronounced concentration gradients, w as compensated by using a carrier solution processed on-line with two alternating solutions. The concentration profiles of the resulting car rier solution and sample plug are similar, a fact that prevents the fo rmation of concentration gradients. Beer's law was followed for pindol ol concentrations of up to 120 mu g ml(-1). Results were reproducible (RSD <1.1%, n=10) and in agreement with those obtained by the referenc e procedure. A sampling rate of 30 samples per hour was attained. (C) 1998 Elsevier Science B.V.