COULOMETRIC DETERMINATION OF THE FLOW-RATE OF SMALL MASSES OF SUBSTANCES .2. APPLICATION TO ONLINE MEASUREMENT OF THE EOX-PARAMETER

Today's microprocessor-controlled coulometric systems can generate com plex functions obtained from the response of the microcoulometric cell . A previously developed procedure for determining the flow-rate (mass per unit time of detected species) has been accomplished by integrati ng, in the software, the full time dependence of the reaction of the c oulometric cell and their electrodes, as well as of the titration curv e. This leads to a time dependence of the measured signal, which has a fast response time without any delay. The titration curves are determ ined by means of various procedures. The applicability of the method i s demonstrated for the case of the continuous analysis of the EOX-para meter (Extractable Organic Halogens X = Cl, Br, I) by coupling the cou lometric detection with a FIA system. Results of continuous measuremen ts of aqueous samples containing different chlorinated compounds as an alytes are presented by taking into account different flow velocities in the FIA system as well as different measuring times. Recovery yield s of the FIA system better than 70% have been obtained.