Trimethyloxonium-mediated methylation strategies for the rapid and simultaneous analysis of chlorinated phenols in various soils by electron impact gas chromatography-mass spectrometry

Utilizing Carbon Dots Derived from Waste Face Masks for Pentachlorophenol Detection

Pentachlorophenol is a very toxic chemical that is used as a pesticide, fungicide, herbicide, wood preservative, etc., and it should be monitored in terms of human health and environmental production. Another environmental problem is the increase in the use of facemasks, especially during the COVID-19 pandemic. This study provides a value added chemicals to sustainability of recycling process. Fluorescent carbon dots (CDs) were synthesized from waste facemasks and investigated their fluorescence sensor performances. UV-Vis and fluorescence spectra of the synthesized carbon dots were recorded in different organic solvents. The sensor properties of these carbon dots against pesticides were investigated, and a 'turn-off' response was observed toward pentachlorophenol. The limit of detection was found 8.5 µM in the linear range from 43.3 µM to 375 µM. This study showed that waste plastics such as facemasks can be recycled to obtain carbon dots, which are used in different technological areas such as photocatalysis, bioimaging, etc., as well as in sensors.

Simultaneous determination of 19 bromophenols by gas chromatography-mass spectrometry (GC-MS) after derivatization

Bromophenols (BPs) are a class of ubiquitous emerging halogenated pollutants. Their 19 congeners are problematically separated and detected. This work described the separation and detection of 19 BP congeners by gas chromatography-mass spectrometry (GC-MS). Investigations into the derivatization of bromophenols were carried out using two silylation reagents (N,O-bis(trimethylsilyl)trifluoroacetamide and N-methyl-N-(trimethylsily)trifluoroacetamide), two alkylation reagents (methyl iodide and trimethylsilyldiazomethane) and acetic anhydride prior to GC-MS analysis. Optimal chromatographic separation, sensitivity, and linearity were achieved after BP derivatization using acetic anhydride, featuring the equipment detection limits of 0.39-1.26 pg and correlation coefficients of 0.9948-0.9999 (linear range: 0.5-250 ng mL-1) for all 19 BP congeners. Furthermore, the simultaneous determination of 19 bromophenols and 19 bromoanisoles, common environmental transformation products of BPs, is also demonstrated. The improved analytical performance on GC-MS after derivatization would benefit investigations on the environmental origins, behaviors and fates of BPs and their environmental metabolites.

Food and environmental safety monitoring platform based on Tb(III) functionalized HOF hybrids for ultrafast detection of thiabendazole and 2-chlorophenol

Development of efficient and intelligent method for detecting harmful agrochemicals in resource-limited settings remains an urgent need to ensure food and environmental safety. Herein, a novel dual-emitting Tb3+-modified hydrogen-bonded organic framework (Tb@TBTC, TBTC is the ligand of HOF-TBTC.) with visible green fluorescence has been prepared through coordination post-synthetic modification. Tb@TBTC can be designed as a fluorescence sensor for the identification of two harmful carcinogenic pesticides, thiabendazole (TBZ) and 2-chlorophenol (2-CP) with high sensitivity, high efficiency and excellent selectivity. Tb@TBTC can also adsorb 2-CP with high adsorption rate. In realistic fruit juice and river water samples, the detection limits of Tb@TBTC toward TBZ and 2-CP are as low as 2.73 μM and 2.18 μM, respectively, demonstrating the feasibility in practical application. Furthermore, an intelligent real-time and on-site monitoring platform for 2-CP detection is constructed based on Tb@TBTC-agarose hydrogel films with the assistance of back propagation neural network, which can efficiently and accurately determine the concentration of 2-CP from fluorescence images through human-machine interaction. This work presents a facile pathway to prepare Tb@HOF fluorescent sensor for food and ecological environment safety, which is highly promising for preventing human disease and improving global public health.