Selective and sensitive on-site colorimetric detection of 4,4′-isopropylidenediphenol using non-enzymatic molecularly imprinted graphitic carbon nitride hybrids in milk and water samples

Abstract

Bisphenol-A (4,4′-isopropylidenediphenol) is widely used in a variety of industries such as food packaging and plastic coatings. Because of the high quantity of BPA, it is incompatible with both terrestrial and aquatic environments. As a result, an approach for detecting BPA is urgently needed. Graphitic carbon nitride (g-C₃N₄) has recently been investigated as a peroxidase-like catalyst for a non-enzymatic colorimetric-based sensor. Herein, environmentally benign molecularly imprinted polymer incorporated on graphitic carbon nitride (MIP@g-C₃N₄) was synthesized by using functional monomer 3-aminopropyl ethoxy silane (APTES) and cross-linker tetraethyl orthosilicate (TEOS) for sensing (Bisphenol-A/BPA). The synthesized MIP@g-C₃N₄ shows high peroxidase-like activity and can catalytically oxidize the colorless substrate (TMB) 3,3′,5,5′-tetramethylbenzidine to produce a blue-colored product ox-TMB. This hybrid material exhibits good linearity that was obtained in the range of 0–50 nM, with the limit of detection as 3.8 nM. Additionally, the developed low-cost and environmentally friendly colorimetric probe was tested for the detection of BPA in food and real-world water samples.