Multi-task flow system for potentiometric analysis: its application to thedetermination of vitamin B-6 in pharmaceuticals

A flow set-up based on the sequential injection analysis concept was design ed. aiming at increased automation and robustness of procedures related wit h potentiometric detection in pharmaceutical control. In this sense, progra mmable set-up calibration, ion-selective electrode characterization, standa rd addition techniques and titration procedures could be carried out withou t any stock solutions conventional handling or modification on the physical structure of the flow system. Evaluation of a flow-through vitamin B-6 sel ective electrode and its application to routine analysis of pharmaceuticals were selected as models to demonstrate the: System potentialities, The sys tem ability to generate in-line calibrating solutions was verified by compa ring the results with those obtained with solutions prepared by the manual procedure. The vitamin B, determination in pharmaceutical products was carr ied out and in-line performed recoveries gave values within 97.4-103.5%. Th e system ability to perform titrations was ascertained using the precipitat ion reaction of vitamin B, with tetraphenylborate. Other profitable feature s such as lower reagent consumption with a low effluent generation volume w ere also achieved. (C) 2000 Elsevier Science B.V. All rights reserved.