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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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier B.V. All rights reserved.)

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., (Copyright © 2021 Elsevier B.V. All rights reserved.)

In this work, 3,4-ethylenedioxythiophene (EDOT) emulsion is prepared by ultrasonication agitation and poly(3,4-ethylenedioxythiophene) (PEDOT) coating is fabricated on a stainless steel wire by electrochemical method from a 0.10M sodium dodecylbenzenesulfonate aqueous solution containing EDOT. The coating is characterized by scanning electron microscopy and Fourier transform infrared spectrophotometry, and it presents cauliflower-like structure. When the resulted PEDOT/steel fiber is used for the headspace solid phase-microextraction of some esters (i.e. methyl anthranilate, dimethyl phthalate, ethyl-o-aminobenzoate, methyl laurate and diethyl phthalate) and their GC detection, the limits of detection (LOD) are ca. 7.8-31 ng L(-1) (S/N=3) and the linear ranges are 0.25-800 μg L(-1). The fiber shows high thermal stability (up to 320 °C), good reproducibility and long lifetime (more than 183 times). It also has good chemical stability. After it is immersed in acid, alkali and dichloromethane for 4h its extraction efficiency remains almost unchanged. Besides esters the fiber also exhibits high extraction efficiency for alcohols and aromatic compounds., (Copyright © 2012 Elsevier B.V. All rights reserved.)

A polyaniline-ionic liquid (i.e. 1-butyl-3-methylimidazolium tetrafluoroborate, [C(4)mim][BF(4)]) composite film coated platinum wire (PANI-IL/Pt) was prepared by electrochemical method for the first time. Scanning electron microscopy image showed that the PANI-IL composite film was even and porous. When the PANI-IL/Pt was used as a fiber for the headspace solid-phase microextraction (HS-SPME) of some benzene derivatives (i.e. 1,3-dimethylbenzene, 1,2-dimethylbenzene, 1,4-dichlorobenzene, 1,2-dichlorobenzene, 1,3,5-trimethylbenzene and 1,2,4-trimethylbenzene), followed by gas chromatographic analysis, it presented excellent performance, which was much better than that of PANI/Pt and commercial polydimethylsiloxane fiber. Hence the fiber was coupled with gas chromatography for the determination of these benzene derivatives. It was found that under the optimized conditions the linear ranges were 0.04-400 μg L(-1) with correlation coefficients above 0.99, the detection limits were 9.3-48.1 ng L(-1) (S/N=3), the relative standard deviations (RSDs) were smaller than 5.1% for five successive measurements with single fiber, and the RSDs for fiber-to-fiber were 5.0-11.1% (n=3) for different benzene derivatives. The proposed method was successfully applied to the extraction and determination of benzene derivatives in waste water and tap water, and the recoveries were 87.1-108.1% for different analytes. Therefore, the PANI-IL/Pt is a promising SPME fiber., (Copyright © 2010 Elsevier B.V. All rights reserved.)