Wang Wenchang,Li Zhi,Wang Wenjin,Zhang Lihong,Zhang Shuaihua,Wang Chun,Wang Zhi
A porous aromatic framework of type PAF-6 was synthesized and explored as a coating onto a steel wire for using in solid-phase microextraction of polycyclic aromatic hydrocarbons (PAHs), phthalate plasticizers, and n -alkanes. The extraction temperature, extraction time, salt concentration, agitation speed, desorption temperature, and desorption time were optimized. This method for SPME resulted in the enrichment factors ranging from 122 to 1090 for PAHs (naphthalene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, pyrene), from 122 to 271 for plasticizers (diisobutyl phthalate, dibutyl phthalate, benzyl butyl phthalate, dicyclohexyl phthalate), and from 9 to 113 for n -alkanes ( n -undecane, n -dodecane, n -tridecane, n -tetradecane, n -pentadecane, n -hexadecane, n -octadecane and n -eicosane). The good extraction of the PAHs is assumed to be due to their π-stacking interaction and hydrophobic effect. The PAF-6 coated fibers are durable and can be reused more than 100 times without significant loss of extraction performance. In combination with GC-MS detection, the method has limits of detection in the range from 0.8 to 4.2 ng L −1 in case of PAHs. The relative standard deviations for five replicate determinations of the PAHs by using one fiber are in the range from 5.2 to 8.5%. When using different fibers, they range from 7.1 to 9.6%. The recoveries of PAHs from water samples at a spiking level of 20 ng L −1 are in the range from 89.5 to 103.1%, with relative standard deviations ranging from 4.0 to 9.3%.
A porous aromatic framework of type PAF-6 was synthesized and used as a novel coating for the solid-phase microextraction of polycyclic aromatic hydrocarbons prior to their determination by gas chromatography with mass spectrometric detection.
The separation of aromatics from aliphatics is essential for achieving maximum exploitation of oil resources in the petrochemical industry. In this study, a series of metal chloride–based ionic liquids were prepared and their performances in the separation of 1,2,3,4-tetrahydronaphthalene (tetralin)/dodecane and tetralin/decalin systems were studied. Among these ionic liquids, 1-ethyl-3-methylimidazolium tetrachloroferrate ([EMIM][FeCl 4 ]) with the highest selectivity was used as the extractant. Density functional theory calculations showed that [EMIM][FeCl 4 ] interacted more strongly with tetralin than with dodecane and decalin. Energy decomposition analysis of [EMIM][FeCl 4 ]–tetralin indicated that electrostatics and dispersion played essential roles, and induction cannot be neglected. The van der Waals forces was a main effect in [EMIM][FeCl 4 ]–tetralin by independent gradient model analysis. The tetralin distribution coefficient and selectivity were 0.8 and 110, respectively, with 10% (mol) tetralin in the initial tetralin/dodecane system, and 0.67 and 19.5, respectively, with 10% (mol) tetralin in the initial tetralin/decalin system. The selectivity increased with decreasing alkyl chain length of the extractant. The influence of the extraction temperature, extractant dosage, and initial concentrations of the system components on the separation performance were studied. Recycling experiments showed that the regenerated [EMIM][FeCl 4 ] could be used repeatedly.
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