In this work, the porous nanomaterial zeolite imidazolate framework-67 (ZIF-67) and tributyl phosphate (TBP) were introduced to co-modify the hollow-fiber liquid-phase microextraction (HF-LPME) for the first time. The extract of five typical flavor enhancers (vanillin, o-vanillin, ethyl vanillin, vanillinol and vanilla acetone) could be directly injected for electrophoretic separation and amperometric detection. The obtained optimum extraction conditions were as followed: supported liquid membrane, tributyl phosphate containing 0.050 mg mL -1 of ZIF-67; donor phase, 10 mL (pH 4.00 adjusted by HCl); acceptor phase, 10 μL (0.20 M NaOH); stirring rate, 500 rpm; extraction temperature, 25 °C; and extraction time, 45 min. Based on the synergistic enrichment effect of ZIF-67 and TBP, this HF-LPME could provide the enrichment factors of 207(V-OH)-890 times (EVA) for the flavor enhancers. This method has been successfully used for the analyses of milk, milk powder and milk tea samples. The limits of detection were 0.15-3.0 μg L -1 (S/N=3), and the recovery data were in the range of 80.1-115.5%. This developed method is easy to operate and has low consumption of solvents and samples, providing a green alternative method for the detection of typical flavor enhancers in dairy products. Besides, the greenness and eco-friendliness of the proposed method was assessed using the green analytical procedure index and analytical eco-scale tools.
The removal of personal care products (PCPs) in aqueous environments is a huge challenge. Traditional powder and magnetic materials are not conducive to complete solid–liquid separation, which hinders their practical application. In this study, the convenient recyclable magnetic self-stirring system combining with n-octanol hollow fiber-liquid phase micro-extraction (HF-LPME), wormhole-like mesoporous carbon (WMC) solid phase and magnetic stirring was constructed to improve the extraction and removal efficiency of the trace PCPs (triclosan, triclocarban, 2, 2′-Dihydroxy-4-methoxybenzophenone, and 2, 4-dihydroxydiphenylketone) in wastewater. The adsorption process of triclosan and 2,2′-dihydroxy-4-methoxybenzophenone on the WMC surface followed the pseudo-first-order kinetics as well as Freundlich isotherm model. Because WMC had oxygen-containing groups and the multiple mesoporous distribution forming the n-octanol microextraction unit and the shearing strength generated by the stir bar in the water sample accelerated the mass transfer efficiency of PCPs, this system had the advantage of simultaneous removal and extraction of four PCPs from wastewater samples. The extraction mechanism involved the hydrophobic force and size effect between the WMC and PCPs. In addition, the factors affecting extraction efficiencies (EEs) were discussed, such as the concentrate of WMC (1 mg/L), rotation rate (400 rpm), extraction time (15 min), and salt concentration (30%). The results indicated that the method possessed a wide linear range (0.05–200 μg L -1 ), and lower limits of detection (LODs) (S/N = 3, 0.005–0.05 μg L −1 ), at the optimal conditions. This method also showed excellent reusability and stability, with higher recovery (88–98%) and fewer relative standard deviations (2.4–6.3%). This work not only minimized secondary pollution from powder adsorbents, but provided an economic and green magnetic self-stirring system and absorbent for the extraction, removal, and determination of typical PCPs pollutants from actual wastewater samples.
危险品化学品经营许可证（带存储）