5,10,15,20-Tetrakis(4-carboxyl phenyl)porphyrin–CdS nanocomposites with intrinsic peroxidase-like activity for glucose colorimetric detection

Here, we describe the design of a novel mimic peroxidase, nanocomposites composed by 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H₂TCPP) and cadmium sulfide (CdS). The H₂TCPP–CdS nanocomposites can catalyze oxidation of substrate 3,3,5,5-tetramethylbenzidine (TMB) in the presence of H₂O₂ and form a blue product which can be seen by the naked eye in 5 min. The mechanism of the catalytic reaction originated from the generation of hydroxyl radical (·OH), which is a powerful oxidizing agent to oxidize TMB to produce a blue product. Then, we developed a colorimetric method that is highly sensitive and selective to detect glucose, combined with glucose oxidase (GOx). The proposed method allowed the detection of H₂O₂ concentration in the range of 4 × 10⁻⁶–1.4 × 10⁻⁵ M and glucose in the range of 1.875 × 10⁻⁵–1 × 10⁻⁴ M with detectable H₂O₂ concentration as low as 4.6 × 10⁻⁷ M and glucose as low as 7.02 × 10⁻⁶ M, respectively. The results provided the theoretical basis of practical application in glucose detecting and peroxidase mimetic enzymes. - Graphical abstract: 5,10,15,20-tetrakis(4-carboxyl phenyl)-porphyrin (H₂TCPP)–CdS nanohybrids were demonstrated to possess intrinsic peroxidase-like activity and used for a glucose colorimetric sensor. - Highlights: • H₂TCPP–CdS nanocomposites were synthesized by a facile one step under mild condition. • H₂TCPP–CdS nanocomposites possess excellent intrinsic peroxidase-like activity. • A sensitive and selective colorimetric sensor for glucose is provided based on H₂TCPP–CdS nanocomposites. • The generation of hydroxyl radical (·OH) decomposed from H₂O₂ is contributed to efficient catalytic