Search

BACKGROUND Pesticide residues in fruits and vegetables threaten food safety. Cleaning before eating is a usual way to remove pesticide residues, so it is very important to find the most efficient cleaning conditions for public health. However, many previous cleaning studies only focused on a single variable which required a large amount of time manpower and material resources. Plackett–Burman design (PBD) and response surface methodology can avoid the earlier‐mentioned problems and have potential in studying the influence and interaction of multiple factors. In this study, the effect of five factors on the removal of triadimefon and boscalid from rape by ultrasonic washing was evaluated through PBD: pH of water, ultrasonic cleaning time, water temperature, initial residual concentration and volume of water. RESULTS: Temperature had a significant effect on the rate of triadimefon removal while the other four factors impacted boscalid removal greatly. A higher temperature was better for the removal rate of triadimefon. Under alkaline environment, when initial residual concentration and cleaning time increased with decreasing water volume, the removal rate of boscalid increased. Furthermore, the interactions among factors were obtained. The regression coefficients of fitting equations about triadimefon and boscalid were 0.9657 and 0.9738, respectively. CONCLUSION: Changing pH of water, cleaning time, water volume and temperature during the washing process of rape through PBD designed experiments represents a valid strategy for improving the removal rate of two pesticides residue. This study provides a reference for ultrasonic cleaning conditions by a sink dishwasher, which has a positive effect on food safety. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

The maximum residue limit (MRL) of emamectin benzoate in mango had not been legislated in China and no work had been done to determine the emamectin benzoate residue in mango. The aim of this study was to investigate the dissipation and terminal residues of emamectin benzoate in mango under field conditions and to assess its safe use. A high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) with modified QuEChERS for analysis of emamectin benzoate was established. It was shown that at fortified levels of 0.005, 0.02 and 0.1 mg/kg, the average recoveries were 72–102% with RSDs less than 8% for intra-day and 81–102% with RSDs less than 9% for inter-day. The half-life of emamectin benzoate in mango was 4.9 days and terminal residues mostly lower than LOQ (0.005 mg/kg) with PHIs of 5, 7 and 10 days except Sichuan province. The dietary exposure risk of emamectin benzoate on mango was negligible depending on the RQ value of 2.77–34.96%. Therefore, it would be unlikely to cause health problems if emamectin benzoate was applied according to the use pattern suggested by the manufacturers on the label. These results would be useful in establishing MRL and providing guidance on the safe use of emamectin benzoate. [ABSTRACT FROM AUTHOR]

Pesticides such as insecticides, fungicides, and herbicides play an important role in the global agricultural industry as they reduce the occurrence of crop diseases, kill pests, and remove weeds. On the other hand, these pesticides are a double-edged sword because they have both acute effects and chronic adverse effects on human health. The widespread use of pesticides has led to their persistence in soil, water, and agricultural products, thus posing a serious threat to public health. Therefore, the removal and analysis of pesticides are critical to protecting human safety and health. When removing pesticides from the environment, it is imperative to ensure high removal efficiency while preventing secondary pollution to the environment. Because of the low concentrations of pesticide residue in the environment, complex matrix, and large throughput of pesticide residue analysis, a low-cost fast pre-treatment technique that has strong selectivity and an enrichment effect on the target pesticide residue, with little environmental impact, is required. Plant biomass-derived biochar is obtained from wheat straw, corn cob, rice husk, etc. This material has a large specific surface area, high pore capacity, tunable surface functional groups, and good environmental compatibility, which make it an inexpensive and efficient adsorbent. Hence, there is a need to systematically review the knowledge regarding the application of plant-based biochar on pesticide removal and pesticide residue analysis. This paper reviews the application progress of plant biomass-derived biochar in the above mentioned two areas over the last decade. The pesticide removal applications include reducing the mobility of pesticides in soil, eliminating the pollution caused by chiral pesticides, loading pesticide-degrading bacteria, and releasing fertilizers sustainably when removing pesticide. As mentioned above, plant biomass-derived biochar has a large specific surface area, a high number of functional groups on the surface, and good environmental compatibility. Therefore, it can effectively remove pesticides or their metabolites from the environment without causing any secondary pollution. During pre-treatment, plan biomass-derived biochar is used as an adsorbent for dispersive solid-phase extraction, solid-phase microextraction, and magnetic solid-phase extraction to selectively adsorb organophosphorus and triazole pesticides in fruits and vegetables, as well as organochlorine pesticides in the aquatic environment. This paper also introduces the adsorption mechanism of plant biomass-derived biochar, where studies based on computational simulations such as the density functional theory, molecular dynamics simulation, and giant canonical Monte Carlo simulation are carefully discussed. The benefits of adopting computational simulations are also mentioned. Finally, this paper summarizes the advantages and disadvantages of using plant biomass-derived biochar in pesticide removal and pre-treatment, as well as the future research trends in this area.

In the title compound, CH(6)N(3) (+)·C(5)H(8)NO(4) (-), there are two independent cations and two independent anions in the asymmetric unit. In the crystal structure, cations and anions are linked by inter-molecular N-H⋯O hydrogen bonds into a three-dimensional network.