alizarin red as a single colorimetric chemosensor for sequential determination of al3+ and cn- ion

We have developed a colorimetric sensing method for quantitative determination of cn- using alizarin red (alr) as a colorimetric sensor of al3+ that the resulting interaction (alr - al3+ complex) indicated photophysical changes upon the addition of al3+ among other cations. in the first step, alr was used for colorimetric detection of al3+ in aqueous solution by the obvious color change. in the second step the produced ensemble (alr- al3+), sensitively and selectively detected a low concentration of cn- via indicator displacement assay system. the colorimetric detection operation is low-cost using alr and al3+ ion and has a simple operation without any further modifications. any enzymatic reactions, separation processes, chemical modifications, and sophisticated instrumentations are also not required in this experiment.