The Development of an Automated HPLC System for the Determination of Trace-Metals in Concentrated Brines and Its Application to Process Monitoring

Methodology based on high performance liquid chromatography (HPLC) has been developed for the determination of trace-metals in concentrated brines. Metal ions, (Al, Ba, Ca, Mg, Sr and Zn) were concentrated quantitatively and isolated from the sodium chloride matrix using a chelating ion-exchange column dynamically coated with the chelating dye xylenol orange. The pH dependence of the uptake of the metals was studied. Using the chelating ion-exchange preconcentration column followed by ion chromatography all the metals studied were determined at the low ng ml-1 level in concentrated brines and linear/workable calibrations were obtained in the concentration range of interest (<100 ng ml-1). The methodology developed was successfully transferred to an automated on-line monitoring system for the determination of Ba, Ca, Mg and Sr in concentrated feed brines used in the chlor-alkali industry. © 1991 Springer-Verlag.