Preparation and characterization of layer-by-layer assembly of thiols/Ag nanoparticles/polydopamine on PET bottles for the enrichment of organic pollutants from water samples

Abstract

In this study, we immobilize thiols/Ag nanoparticles/polydopamine (thiols/AgNPs/PDOPA) sorbents onto the inner walls of 100 mL of PET bottles via layer-by-layer assembly technique. The polydopamine film, resulting from selfpolymerizing of dopamine in alkaline solution, is responsible for the firm adhesion of sorbents and reduction of Ag⁺ to AgNPs. AgNPs increase the specific surface areas of the bottles and supply hydrophobic thiols ad-layers through Ag–S bonds. Organic analytes can be sorbed via hydrophobic interaction with thiols on AgNPs surface and/or π–π stack interaction with PDOPA film. The enrichment of organic contaminants using these bottles can be performed by manual vibration of bottles loading with water samples for 1 min and standing for a certain time. After discarding the aqueous solution, the targets are collected with acetonitrile. In this novel kind of solid-phase extraction (SPE) method, no special instruments and electricity power are required and enrichment of organic contaminants can proceed during transport or storage of water samples, which will save the analytical time. Water samples can be stored in the bottles safely at room temperature and photocatalytic degradation, biodegradation of organic analytes are avoided due to the brown color of the bottle and antibacterial activity of AgNPs. The cost for water sample storage and loss of analytes during sample transport and storage can be decreased. The new SPE method is successfully applied to extract target analytes including two alkylphenols, two phthalate esters and six polycyclic aromatic hydrocarbons from real water samples. The recoveries of targets are ranged from 70–120%, and the detection limits are in the range of 0.1–68 ng L⁻¹.