The environmental pollution of 2,4,6-tribromophenol (TBP) has attracted attention. Based on an urgent need for the better provision of clean water, in situ determination of TBP is of great importance. Here, a facile and effective approach for detecting TBP is developed, based on coupling molecular imprinting technique with electrodeposition of chitosan (CS) on the gold electrode. The TBP imprinting CS film was fabricated by using CS as functional material and TBP as template molecule. The experiments show that the morphologies and electrochemical properties of the imprinted film sensor was different from non-imprinted film electrode. The current of the imprinted film was linearly proportional to the TBP concentration, with a wide linear range of 1.0 × 10−7mol·L−1to 1.0 × 10−3mol·L−1. By selecting drop-coating method as a reference for controlled trials with the same functional material, the results illustrated that the electrodeposition enjoyed a widely linear range advantage.Keywords:2,4,6-tribromophenol;chitosan;molecular imprinting;electrodeposition
Ma Xiuling,Wu Dan,Huang Limei,Wu Zhenyue,Xiang Shengchang,Chen Sheng
Abstract 2,4,6-Tribromophenol has been used as flame retardant and is a synthetic intermediate of the most important brominated flame retardants produced. In this work, a novel electrochemical sensor for determining 2,4,6-tribromophenol was fabricated by surface molecular imprinting technology, in which core–shell nanoparticles modified with (3-chloropropyl)trimethoxysilan and polyethylenimine were used as functional monomer, and 2,4,6-tribromophenol as template, ethylene glycol dimethacrylate as cross-linker. The electrochemical behavior the modified electrodes was investigated by electrochemical impedance spectroscopy and differential pulse voltammetry. The results showed that the imprinted electrode was significantly different from the non-imprinted electrode. The imprinted electrode had ascendant selective recognition ability, exhibited a low detection limit (1.51 × 10 −8 mol/dm 3 ) and good repeatability (RSD is 4.35 % for 5 times) for the detection of 2,4,6-tribromophenol. Graphical abstract
AimsThis study aimed to ascertain the active substances in the hydroponic solution of Ulva (U.) fasciata (HSUF) and their effects on antibiotics resistance of pathogenic bacteria Vibrio alginolyticus (Va.) at environmental levels.Methods and ResultsAnalytical results of HSUF by solid-phase extraction and gas chromatography-mass spectrometry showed that HSUF contained rich active substances and dominated by 2,4,6-tribromophenol, acetal, mono (2-ethylhexyl) phthalate and 2- (4-hydroxybenzene) ethanol, etc. Thereinto, 2,4,6-tribromophenol had the lowest minimal inhibitory concentrations (MICs) of 64–128 μg mL−1 for Va. strains. The rich antibacterial substances of HSUF inhibited 47%-63% of isolated Va. strains. After 20 generations of subculture for Va. strains in three dilutes (1/2 (HT), 1/20 (MT) and 1/50 (LT)) of HSUF (20 g L−1), the resistance to streptomycin of Va. S1 and Va. M3 changed from intermediate resistance ability to susceptible level. The large promotion of reactive oxygen species was observed in different HSUF levels, but the biofilm formation of Va. S1 did not changed significantly. Transcriptome sequencing of Va. S1 demonstrated that antibiotic resistance gene lpxA was down-regulated at different HSUF levels.ConclusionsLive U. fasciata excreted a variety of active secondary metabolites (SMs) in HSUF, which exhibited strong inhibitory effects on three isolated Va. strains. HSUF changed the antibiotic resistance of Va. Strain, especially at a higher HSUF concentrations.
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