Spectrophotometric determination of trace levels of allura red in water samples after separation and preconcentration.

A new, simple, rapid and sensitive solid phase extraction procedure based on separation and preconcentration of trace levels of allura red in water samples on MCI GEL CHP20P column system has been established. Optimal analytical conditions including pH, amount of allura red, flow rates of sample and eluent solutions, resin amount, sample volumes, etc. were investigated. The interference effect of some cations and anions was also studied. Preconcentration factor was found as 250. The detection limit (3 sigma) of the reagent blank for allura red was 2.35 μg L(-1). The determination of allura red levels in samples was performed by using spectrophotometry at 506 nm. The relative standard deviations of the procedure were below 7%. The validation of the presented procedure was performed by the method of standard addition. The procedure was successfully applied to the determination of trace levels of allura red in tap water and waste water samples.