Chromazurol S solution is widely used as a colorimetric reagent for the detection and quantification of metal ions, especially aluminum, in environmental, biological, and industrial samples. It forms stable, colored complexes with metal ions, allowing for sensitive measurement using spectrophotometric methods. The solution is particularly effective in water quality testing, where trace levels of aluminum need to be monitored due to health and environmental concerns. It is also applied in clinical laboratories for analyzing aluminum content in biological fluids, such as serum or urine, especially in patients with kidney disease who are prone to aluminum accumulation. In addition, Chromazurol S is used in combination with surfactants or other reagents to enhance selectivity and sensitivity in flow injection analysis and sensor development. Its ability to change color upon metal binding makes it useful in developing visual test kits and solid-phase extraction systems for on-site metal detection.