STATIONARY-PHASE FOR THE DETERMINATION OF FLUORIDE AND OTHER INORGANIC ANIONS

A pellicular anion-exchange column was developed for the determination of inorganic anions including fluoride and oxyhalides such as chlorite, chlorate and bromate. Compared with conventional latex-agglomerated resins, the new anion exchanger allows the retention of fluoride well out of the water dip with elution of sulfate in less than 15 min using a carbonate-hydrogencarbonate eluent under isocratic conditions. Because the ethylvinylbenzene-divinylbenzene substrate is highly cross-linked, the new separator is solvent compatible, thus allowing the use of organic solvents to alter the selectivity of the separation, and also to remove organic contaminants from the column. The separation characteristics of this column are presented and various applications are discussed.