Developing an Ultrasensitive Colorimetric Assay for Low‐abundance Iron‐tetraamido Macrocyclic Ligand (Fe−TAML) Catalyst.

Fe−TAML is a well‐known green catalyst for bleaching and wastewater treatments. Quantitative analysis of Fe−TAML is important to understand its activity and lifetime in these applications. However, because of its sub‐parts‐per‐million dosage and the presence of interfering substances, it is very challenging to detect Fe−TAML specifically and quantitatively at this level. To overcome these issues, we develop a quantitative assay for Fe−TAML, which is based on its catalytic reaction with a blue dye (Reactive Blue 19) and H2O2. This assay is highly specific, and shows no interference for iron species. Moreover, the colorimetric assay can be carried out for fast screening of Fe−TAML with a limit of detection (LOD) of 0.39±0.08 μg L−1. Finally, this assay was successfully applied to understand the stability of Fe−TAML under various conditions, and monitoring the activity of Fe−TAML during wastewater treatments. [ABSTRACT FROM AUTHOR]