Sorbents for the Removal of Organic Compounds that Interfere with the Determination of Bromide in Natural Waters

Abstract

A number of porous polymeric solid phase extracting sorbents were tested for selective removal of organic compounds from aqueous solutions in which bromide ions are to be determined, and the best were recommended. A methodology was developed to achieve selectivity as to bromide ion, the concentration of which should not change in the sample during sample pretreatment. In order to selectively remove dissolved organic compounds from water matrix intended for analysis for bromide, sample acidification to pH 2.0 is recommended followed by sample filtration through the reverse-phase sorbent of LC-18 type. In these conditions, 20 mg/dm3 of fulvic acid characteristic of Dnipro River water are effectively separated from 0.1 mg/dm3 Br- with minimal losses of the latter. Sample acidification promotes the formation of molecular non-dissociated forms of organic compounds in solution, which are effectively separated from bromide ions on reverse-phase sorbents. Artesian water and sea water contaminated with oil spills were analyzed using passing through LC-18 sorbent. Results of natural water analysis by photometric and ICP-MS methods prove the applicability of the approach proposed.