Search

A Fe‐porphyrin covalent organic framework (Fe‐PorCOF) was prepared through a postmodification strategy and characterized using different techniques. Fe‐PorCOF exhibits an inherent peroxidase/oxidase mimetic catalytic activity and sharply accelerates chemiluminescence (CL) reactions between luminol and hydrogen peroxide (H2O2) or dissolved oxygen (O2) under alkaline conditions. The catalytic role was attributed to a significant increase in production of reactive oxygen species. Using the imminent peroxidase mimetic catalytic activity of Fe‐PorCOF, a new CL method was developed for determination of H2O2 over a linear range from 0.01 to 10.0 μmol·L−1 and with a limit of detection of 5.3 nmol·L−1. The combination of the peroxidase mimetic catalytic activity of Fe‐PorCOF with the catalytic activity of glucose oxidase on glucose oxidation presents a sensitive CL method for glucose assay. The linear range and the detection limit for glucose were 0.05–8.0 μmol·L−1 and 4.0 nmol·L−1, respectively. The practicability of this method was assessed by determination of glucose in human sera. As a peroxidase/oxidase mimetic, Fe‐PorCOF is easy to prepare and exhibits good catalytic efficiency in the luminol reaction. We believe that this strategy will promote the development of a CL field with functional COFs as a catalyst. [ABSTRACT FROM AUTHOR]

[Display omitted] • Fluorescent TpPa-1@FL was prepared with a post-synthetic modification strategy. • TpPa-1@FL was employed an energy acceptor to construct CRET system. • The CRET signal was enhanced by bovine serum albumin. • The CRET system can determine H 2 O 2 and uric acid in biological samples. A simple and feasible strategy was developed for the preparation of fluorescent covalent organic frameworks (COFs) TpPa-1@FL. The TpPa-1–1@FL was prepared via a self-assembly strategy by soaking non-fluorescent COFs TpPa-1 into strong fluorescent fluorescein (FL) solution. A chemiluminescence resonance energy transfer (CRET) system was constructed by the combination strong fluorescent TpPa-1@FL with TCPO-hydrogen peroxide (H 2 O 2) reaction. The chemiluminescence (CL) signal of the system was further improved by the addition of bovine serum albumin (BSA). The CRET system can determine H 2 O 2 with a linear range response from 5.0 µmol/L to 20.0 mmol/L and a detection limit of 1.1 µmol/L. The CRET system was further exploited for indirect detection of uric acid with coupling of uricase. A good linear relationship was obtained for uric acid in the 10.0–400.0 µmol/L concentration range with a detection limit of 3.8 µmol/L. The practicability of this method was assessed by the determination of uric acid in real samples of human serum and urine. [ABSTRACT FROM AUTHOR]

Covalent organic frameworks (COFs) are considered to be a promising support material for catalyst due to their highly ordered porous structure. Here, a core-shell structured Fe 3 O 4 magnetic covalent organic framework (Fe 3 O 4 @COF) was synthesized and employed to provide basic sites for immobilization of gold nanoparticles (AuNPs). The AuNPs was in-situ immobilized on the shell of Fe 3 O 4 @COF via a citrate reducing method. The Fe 3 O 4 @COF-AuNP had convenient magnetic separability and exhibited excellent mimicking peroxidase-like activity in catalyzing chemiluminescence (CL) reaction of luminol with hydrogen peroxide (H 2 O 2). With acetylcholine chloride (ACh) as substrate of acetylcholinesterase (AChE), a CL method was exploited for sensitive detection of organophosphorus pesticide triazophos due to its irreversible inhibiting effect on the AChE activity and subsequently influences the production of H 2 O 2 under the condition of choline oxidase (ChOx). This method gave a good linearity for triazophos in the range of 5.0–300.0 nmol L−1, and a limit of detection (LOD) of 1 nmol L−1 was acquired. The applicability of this method was verified by the determination of triazophos in different spiked vegetable samples. [Display omitted] • Core-shell structured magnetic covalent organic framework is prepared for the immobilization of gold nanoparticles. • Fe 3 O 4 @COF-AuNP exhibits excellent mimicking peroxidase-like activity. • Triazophos can be sensitive detected through hindering enzymatic H 2 O 2 production. • Fe 3 O 4 @COF-AuNP can be recycled and shows efficient reusability. [ABSTRACT FROM AUTHOR]