A molecular-imprinted polymer nanoparticles (MIP-NP) for the selective preconcentration of 2,4-dichlorophenoxyacetic acid (2,4-D) is described. It was obtained by precipitation polymerization from methacrylic acid (the functional monomer), ethylene glycol dimethacrylate (the cross-linker), 2,2′-azobisisobutyronitrile (the initiator) and 2,4-D (the template molecule) in acetonitrile solution. The MIP-NPs were characterized by thermogravimetric analysis, and by scanning electron microscopy. Imprinted 2,4-D molecules were removed from the polymeric structure using acetic acid in methanol (15:85 v/v %) as the eluting solvent. The sorption and desorption process occur within 10 min and 15 min, respectively. The maximum sorbent capacity of the molecular imprinted polymer is 89.2 mg g−1. The relative standard deviation and limit of detection for water samples by introduced selective solid phase extraction were 4.2% and 1.25 μg L−1, and these data for urine samples were 4.7% and 1.80 μg L−1, respectively. The method was applied to the determination of 2,4-D in the urine and different water samples.

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BACKGROUND: The high spread rate of coronaviruses, specifically severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has raised concerns about the spread of the disease in crowded occupational environments. The risk of occupational exposure to coronavirus depends on the type of industry and the nature of work. Currently, most countries are working for reactivating their economies and need to improve working conditions for a safe situation during the COVID-19 pandemic. OBJECTIVE: The present work aimed to investigate the current engineering and administrative control measures, which are necessary to protect workers against COVID-19 in workplaces. METHODS: The current strategies, including engineering control, administrative control, personal protective equipment, and their efficiencies, were reviewed and discussed. RESULTS: Reviewing the literature indicated that a collection of control approaches should be implemented for an effective control of the virus. Control measures could be selected based on the risk of exposure to COVID-19. The results also revealed that relying solely on a specific control measure could not effectively control the outbreak. CONCLUSION: In conclusion, employers and health professionals must continually monitor international and local guidelines to identify changes in recommendations to make their workplaces safer. Establishment of an expert team in any workplace for the implementation of more effective control measures is warranted, as well.

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