A flow-cell optosensor for monitoring aluminium(III) based on immobilised eriochrome cyanine R (ECR) and reflectance spectrophotometry

An optosensor for the determination of aluminium based on the use of eriochrome cyanine R (ECR) immobilised on XAD-2 and diffuse reflectance spectrophotometry has been developed. This system consists of a flow-cell containing the reagent phase which stimulates the distal end of the bifurcated fibre, which in turn is connected to the source lamp and detector. The response of the sensor was found to be reproducible with a response time of < 5 min, and a sensing range of 0.34–10.75 ppm Al. Fluoride solution provides a rapid method for regeneration of the sensor after reaction with aluminiu. Interferences from other ions were also studied.