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• A convenient analytical method for bifenazate acaricide in citrus was developed. • The method was based on QuEChERS and modified with the oxidation of ferric chloride. • The bifenazate and bifenazate-diazene can be simultaneously determined. • The detection of bifenazate acaricide with this method is time-saving and accurate. Bifenazate is widely recognized as an effective acaricide for citrus production in various regions. Detecting both the parent compound of bifenazate and its metabolite, bifenazate-diazene, simultaneously can be challenging owing to their tendency to undergo chemical interconversion. Current methods developed for detecting bifenazate or bifenazate-diazene residues often involve lengthy incubation periods and may not effectively separate the two compounds. In this study, we developed a convenient and fast method based on a modified QuEChERS method assisted by oxidants to concurrently detect bifenazate and bifenazate-diazene. Based on preliminary analysis, it appears that ferric chloride has the ability to react with a reducing substance present in citrus, which may prevent the reduction of bifenazate-diazene. The method was validated and applied in a field trial. This work reports a novel strategy to establish a balanced 'neutral' condition to create a potential method for efficient determination of bifenazate acaricide residues in fruit matrices. [ABSTRACT FROM AUTHOR]

[Display omitted] • Removal of organophosphorus pesticides from tea infusion was first reported. • The removal rate of pesticides by modified materials was greatly improved. • Hydrophobic interaction played a dominant role in the adsorption process. • There were no significant changes in tea infusion quality after adsorption. The abuse of organophosphorus pesticides (OPPs) in tea planting makes it easy to transfer from tea into its infusion, bringing potential health risks to consumers. Thus, it is essential to adopt reliable techniques to remove OPPs from tea infusion. In this study, three treatment methods were used to modify carbonized bacterial cellulose (CBC) to improve its adsorption performance. Among them, CBC treated by hydrazine hydrate (N -CBC) had the best adsorption effect, whose removal rate for dicrotophos is 13 times that of CBC. The in-depth study of adsorption mechanism proved that hydrophobic interaction dominated the adsorption of OPPs onto N -CBC. The pseudo-second-order kinetic model and Langmuir isotherm model were more suitable to describe the process. Additionally, there were no significant changes in tea infusion quality after N -CBC treatment. This work clarifies that N -CBC benefitted from simple preparation method, excellent adsorption performance and unique adsorption mechanism has potential applications in tea infusion. [ABSTRACT FROM AUTHOR]

Biochar materials have been widely employed for adsorption of pollutants, which necessitates further consideration of their efficiency and safety in environmental remediation. In this study, a porous biochar (AC) was prepared through the combination of hydrothermal carbonization and in situ boron doping activation to effectively adsorb neonicotinoids. The adsorption process was shown to be a spontaneous endothermic physical adsorption process, where the predominant interaction forces between the acetamiprid and AC were electrostatic and hydrophobic interactions. The maximum adsorption capacity was 227.8 mg g−1for acetamiprid and the safety of AC was verified by simulating the situation where the aquatic organism (D. magna) was exposed to the combined system (AC & neonicotinoids). Interestingly, AC was observed to reduce the acute toxicity of neonicotinoids owing to the reduced bioavailability of acetamiprid in D. magna and the newly generated expression of cytochrome p 450. Thus, it enhanced the metabolism and detoxification response in D. magna , which reducing the biological toxicity of acetamiprid. This study not only demonstrates the potential application of AC from a safety perspective, but also provides insight into the combined toxicity caused by biochar after adsorption of pollutants at the genomic level, which fills the gap in related research. [ABSTRACT FROM AUTHOR]

[Display omitted] • Effective methods for 6PPD and 6PPDQ in complex samples were established firstly. • The developed methods were applied to real samples successfully. • The existence of 6PPD and 6PPDQ in fish samples was confirmed for the first time. N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine (6PPD) and N-(1,3-dimethylbutyl)-N′-phenyl-p-phenylenediamine-quinone (6PPDQ) can pose a threat to human health through the food chain because of their ubiquitous presence in the environment and the biotoxicity on organisms. In this work, we developed modified QuEChERS methods coupled with high performance liquid chromatography tandem mass spectrometry (HPLC/MS-MS) to explore whether 6PPD and 6PPDQ are present in fish and honey. The proposed methods showed acceptable limits of quantification (0.00043-0.001 mg/kg), linearity (R2 > 0.99), recovery (73.3%-108.3%), matrix effect (70.4%-95.6%) and repeatability (RSD < 8.4%). Accordingly, 6PPD and 6PPDQ have been discovered in snakehead, weever and Spanish mackerel fish, while none of which have been detected in the honey samples. The results of our work contributed to increasing public attention to 6PPD and 6PPDQ in agricultural products and provided important reference for the analysis of them. [ABSTRACT FROM AUTHOR]