A robust multisyringe system for process flow analysis - Part I. On-line dilution and single point titration of protolytes

A robust multichannel manifold involving a multisyringe piston pump used fo r performing process flow analysis is proposed. The simultaneous sequential determination of two analytes with a sampling frequency of 97 injections p er hour is demonstrated. A robust and rapid continuous flow titration syste m, including a predilution step, was developed. A quantitative dilution, av oiding the need for diluting the standards too, is achieved in two steps by first splitting the concentrated sample stream and further dilution in a m ixing chamber. A wide range of dilution grades (from 80 to 1150) can be eas ily implemented by software instructions, without the necessity of mechanic al reconfiguration of the manifold. The resulting system gives medium or lo w dispersion peak signals with a sampling frequency of over 75 injections p er hour for off-line diluted samples, and more than 33 injections per hour for concentrated samples. The proposed assemblage allows the automation of the single point flow injection titration procedure for the assay of acids and bases in concentrated process solutions. Recoveries of 97.5-103% were f ound with a maximum RSD value of 5%.