RESUMO
The detection of antibiotics and pesticides are of great significance since their residues threaten the health of human beings by accumulation. However, most traditional solid chemical sensors are suffer from the limitations of low sensitivity and economic practicability because of the aggregating nature and unstable of solid sensors. Herein, a new luminescent sensor 1@PMMA (1, [(ZnL)·H2O]n (H2L = 5-(4-(pyridin-4-yl)benzamido)benzene-1,3-dioic acid); PMMA = poly(methyl methacrylate)) was successfully prepared. Notably, the polymer matrix provided the chemical protection for MOF particles. The as fabricated 1@PMMA was stable in milk, honey and egg as well as exhibited strong blue emission under ultraviolet light irradiation, which can act as luminescent probe for detecting antibiotics and pesticides. More interestingly, 1@PMMA exhibited visual, real-time and recyclable detection of antibiotics ornidazole (ODZ) and pesticides 2,6-dichloro-4-nitrobenzenamine (DCN) in real food samples. This work shows that the luminescent MOF-based mixed matrix membranes could be applied as good candidates for sensing analytes in practical application.
Assuntos
Antibacterianos , Contaminação de Alimentos , Estruturas Metalorgânicas , Praguicidas , Antibacterianos/análise , Estruturas Metalorgânicas/química , Praguicidas/análise , Contaminação de Alimentos/análise , Zinco/análise , Zinco/química , Polimetil Metacrilato/química , Leite/química , Medições Luminescentes/métodos , Mel/análise , Animais , Ovos/análise , Membranas Artificiais , Análise de Alimentos/métodos , Limite de DetecçãoRESUMO
Radiation measurements were conducted at 22 cabinet X-ray systems in Beijing, China, between 2015 and 2019. The median dose rates in the closed-drapes position were 0.11, 0.14, 0.12, 0.14, 0.34 and 0.17 µGy h-1 at the operator position and 5 cm from the surface of the left side, right side, top, entrance and exit, respectively. When a scattering object was passed through the entrance/exit (open-drapes position), the dose rates of eight systems ranged from 1.19 to 6.72 µGy h-1 (median: 3.75 µGy h-1). From 2015 to 2019, we monitored the personal dose equivalent Hp (10) 589 times. The personal dose equivalent of three workers exceeded 1 mSv year-1. However, the integrity of equipment shielding needs to be checked regularly to ensure safe operation. The regulation of radiation protection by employers, technician support institutes or government departments is thus warranted to limit the radiation exposure of workers and the public.