Colorimetric and electrochemical assay for dual-mode detection of di-2-ethylhexyl phthalate based on hemin-graphene nanocomposites

Di-2-ethylhexyl phthalate (DEHP) is one of the phthalic acid esters (PAEs) that can impact human health and increase the risk of cancer. In this study, we report a dual-mode method for detecting DEHP using hemin-graphene (H-Gr) hybrids and DEHP aptamers. The H-Gr nanocomposites possess inherent peroxidase-like activity, which can catalyze the chromogenic substrate TMB to produce a blue oxidized product (oxTMB). Additionally, H-Gr can be used as an in situ probe for electrochemical detection. And DEHP aptamer is added as the biological recognition element. Due to its specific recognition properties, the DEHP-aptamer complexes formed inhibit the enzymatic activity and reduce the electrochemical signal of H-Gr. As a result, colorimetric and electrochemical methods were developed for detecting DEHP with a linear relationship ranging from 2.00 × 10−10 − 1.00 × 10−7 g·L−1 and 1.00 × 10−10 − 1.00 × 10−7 g·L−1, respectively. In summary, our study presents a sensitive, rapid, and simple dual-mode strategy for detecting DEHP and has the potential for practical use in detecting DEHP in water samples.