Jiao Zhao,Yan Zhu,Yang Jiao,Jinyan Ning,Yaling Yang
A novel two-step extraction technique combining ionic-liquid-based dispersive liquid–liquid microextraction with magnetic solid-phase extraction was developed for the preconcentration and separation of aflatoxins in animal feedstuffs before high-performance liquid chromatography coupled with fluorescence detection. In this work, ionic liquid 1-octyl-3-methylimidazolium hexafluorophosphate was used as the extractant in dispersive liquid–liquid microextraction, and hydrophobic pelargonic acid modified Fe 3 O 4 magnetic nanoparticles as an efficient adsorbent were applied to retrieve the aflatoxins-containing ionic liquid. Notably, the target of magnetic nanoparticles was the ionic liquid rather than the aflatoxins. Because of the rapid mass transfer associated with the dispersive liquid–liquid microextraction and magnetic solid phase steps, fast extraction could be achieved. The main parameters affecting the extraction recoveries of aflatoxins were investigated and optimized. Under the optimum conditions, vortexing at 2500 rpm for 1 min in the dispersive liquid–liquid microextraction and magnetic solid-phase extraction and then desorption by sonication for 2 min with acetonitrile as eluent. The recoveries were 90.3–103.7% with relative standard deviations of 3.2–6.4%. Good linearity was observed with correlation coefficients ranged from 0.9986 to 0.9995. The detection limits were 0.632, 0.087, 0.422 and 0.146 ng/mL for aflatoxins B 1 , B2, G1, and G2, respectively. The results were also compared with the pretreatment method carried out by conventional immunoaffinity columns.
Zaizhi Liu,Yanlong Qi,Mengling Gui,Chunte Feng,Xun Wang,Yang Lei
A Brønsted acid ionic liquid, 3-methyl-1-(4-sulfonylbutyl) imidazolium hydrogensulfate ([HO3S(CH2)4mim]HSO4), was used for the first time for the preparation of a sulfonated carbon catalyst. The catalyst was prepared from the residue obtained after recovery of the essential oil from the leaves of Cinnamomum longepaniculatum. The sulfonated carbon catalyst with an amorphous structure attained high acidic efficiency at a sulfonation temperature of 200 °C for 2 h of sulfonation time, and was characterised. SEM morphologies revealed that the carbon catalyst consisted of uniform carbon microspores. FTIR analysis, elemental analysis, and X-ray photoelectron spectroscopy revealed that the sulfonic acid group was successfully introduced on the surface of the sulfonated carbon catalyst. The result of TG analysis showed that the obtained sulfonated carbon catalyst has high thermal stability. Good acid and catalytic activity of the obtained sulfonated carbon catalyst were observed for the preparation of ellagic acid and gallic acid, which is comparable to those of diluted sulfuric acid and a sulfonated carbon catalyst that had been prepared with concentrated sulfuric acid. The excellent reusability of the sulfonated carbon catalyst was also confirmed by repeated experimental trials. In summary, the sulfonated catalyst derived from the residue obtained after recovery of essential oil from the leaves of C. longepaniculatum is an economic, eco-benign and promising substitute for traditional mineral acid catalysts for acidic catalysis in industrial applications.
危险品化学品经营许可证（带存储）