Efficiency and characteristics of solid-phase (ion-exchange) extraction for removal of Cl- matrix

Certain types of samples contain chloride in concentrations that are too high to accurately determine other anions by ion chromatography without any pretreatment. One of the most widely used approaches for such samples is matrix elimination using disposable cartridges containing a cation-exchange resin in the Ag+ form. The efficiency and characteristics of the commercially available cartridge for Cl- removal were tested by the on-line connection of the cartridge effluent to an inductively coupled plasma mass spectrometer. Displacement efficiency of Ag+ ions and loading capacity of the cartridges were studied at different flow-rates. Significant amounts of silver were detected in the effluent, which were attributed to colloidal AgCl as well as dissolved Ag+ ions. Because silver ions can cause irreversible damage to the analytical column, an Ag cartridge followed by an on line filter (pore size 0.22 microm) and cartridge in the H3O+ form were proposed for improvement of this sample pretreatment technique for chloride removal.