Flow-injection extraction spectrophotometric determinatin of chromium(VI) with the benzyltributylammonium cation

Abstract Chromium(VI) can be determined spectrophotometrically at 365 nm after flow-injection extraction into chloroform of the ion associate benzyltributylammonium dichromate. The carrier stream was distilled water, merged with 1.0 M sulphuric acid solution, the reagent stream was 0.5% (w/v) benzyltributylammonium chloride solution. The injection rate was 20 h −1 . The calibration graph was linear up to 20 μg ml −1 and the detection limit (3 × baseline noise) was 0.5 μg ml −1 Cr(VI) based on 250-μl injection volumes. The system has been applied to the determination of chromium in steels.