Smartphone-assisted colorimetric sensing hydrogels based on MnO2 NFs nanozyme for highly sensitive and rapid detection of tert-butylhydroquinone in edible oils.

Inspired by the free radical scavenging mechanism of tert-butylhydroquinone (TBHQ), smartphone-assisted colorimetric sensing hydrogels based on MnO2 nanoflowers (MnO2 NFs) nanozyme for TBHQ detection was developed. MnO2 NFs with excellent oxidase-like activity was successfully synthesized through the thermal decomposition of KMnO4. These MnO2 NFs nanozyme could produce O2- and ·OH radicals, converting colorless TMB into blue oxTMB. The presence of TBHQ neutralizes these radicals, decreasing the absorbance at 652 nm. This offers a highly sensitive and quantitative method for detecting TBHQ in edible oils, with a linear detection range of 0.5-42 μg mL-1 and a low detection limit of 0.087 μg mL-1. Additionally, a smartphone-assisted hydrogel was designed for visual and sensitive TBHQ detection. The results from this method closely matched those obtained through high-performance liquid chromatography, presenting an innovative and efficient approach for rapid TBHQ detection in edible oils.