Ion chromatographic determination of bromate in drinking water by post-column reaction with fuchsin.

Bromate deriving from ozonation treatment of bromide containing waters are analyzed by ion-exchange chromatography with spectrophotometric detection after post-column reaction with fuchsin in low pH medium. An anion-exchange column was used with 2.7 mM carbonate-0.3 mM hydrogencarbonate eluent. The eluent from the column was then allowed to react with a SO2-reduced fuchsin solution and then with a diluted HCl solution at 65 degrees C. The developed colour of the final product was measured spectrophotometrically at 530 nm. Linearity was checked up to 50 micrograms/l with a 200-microliter injection loop (r2 = 0.9997) and up to 100 micrograms/l of bromate with 100 microliters loop (r2 = 0.9939). Nitrate, sulfate, bromide, phosphate, fluoride did not interfere at 100 mg/l concentration level; only nitrite at concentration levels greater than 3 mg/l caused partial overlapping with bromate peak, but this value is not likely to occur in common drinking water. The detection limit (3 sigma) is 0.1 microgram/l (1 microgram/l propagation error approach).