RESUMEN
Preparation of highly active and cost-effective electrode materials is of great interest in electrochemical detection. In this study, a simple urushiol-templated solvothermal method combined with calcination was proposed to fabricate N-doped three-dimensional graphene (3D-G) with Mn-doped Fe3O4 nanoparticles loaded on the surface (Mn-Fe3O4/3D-G). Because of the large active surface area, porous channel and high loading ratio of Mn-Fe3O4 nanoparticles, as-prepared Mn-Fe3O4/3D-G sensor showed high activity on the determination of 4-nitrophenol (4-NP), which are much improved from the control un-modified samples. The wide linear concentration range (5-100 µM), low detection limit (19 nM) and satisfactory recovery of 4-NP in various water samples (98.38-100.41%) indicated that the Mn-Fe3O4/3D-G electrode can be potentially used for real-world applications. This study gives a simple but meaningful strategy for constructing transition metal oxide/graphene composite materials with high electrocatalytic activity.
RESUMEN
OBJECTIVE: To investigate the effect of phthalates exposure from drinking water on children's intelligence and secretion of thyroid hormone. METHODS: Two villages in S County were selected randomly as polluted area and control area according to the distance from the Shaying river basin. Phthalates including DEP, DBP, DMP, DEHP were measured both in the river water and drinking water using HPLC method. Children aged 8 to 13 years old studying in the village primary school were recruited by cluster sampling (n = 154). The combined Reven Test was used to test children intelligence and ELISA method was used to determined thyroid hormone levels. RESULTS: The concentrations of phthalates (DEP, DBP) were exceeding standards of surface water quality in any of the three sections of the river. Compared to the control area, the concentration of DEP and DBP in drinking water were significant higher in the polluted area than that in control area (P < 0.05). Children from polluted area had significant higher FT4 concentration compared to children from control area (P < 0.05). Intelligence level in children from polluted area was lower than that from control area (P < 0.05). CONCLUSION: The drinking water has been polluted by Shaying river and thyroid hormones levels of children were affected in the polluted areas. It is necessary to verify if this change is related to the phthalates.