FLOW-INJECTION ANALYSIS OF FLUORIDE IN ELECTROPLATING BATHS WITH POTENTIOMETRIC DETECTION

A high dispersion FIA system with a fluoride selective and a double ju nction reference electrode in cascade arrangement was developed for th e determination of the fluoride content in chromium electroplating bat hs. The analyses of seven synthetic baths prepared in the laboratory a nd two samples provided by the industry gave results with a mean recov ery value of 100.5%, and a mean variation coefficient of 1.6%. These d ata were better than those obtained by the EDTA complexometric titrati on, the reference technique, with a mean recovery of 94.0% and a mean variation coefficient of 7.5%. The sampling rate for the FIA manifold was 20 samples per hour.