Determination of phthalate esters in fat-containing foods by packed nanofiber solid-phase extraction column and gas chromatography

A new method for simultaneous determination of four phthalate esters （ PAEs） in commercial fat-containing foods was developed by the combination of a packed nanofibers column based on solid-phase extraction with gas chromatography-flame ionization detector （ GC-FID ）. Conditions for obtaining optimum extraction efficiency such as extraction solvents, morphologies of adsorbent, ion strength and pH were investigated and optimized in detail. Under the optimized conditions, the limits of detection （LODs） found for dibutyl phthalate （DBP） , butyl benzyl phthalate （BBP）, diethyl hexyl phthalate （DEHP） and di-n-octyl phthalate （DNOP） were 50, 25, 50 and 25 ng/g, respectively. Good linearity of four PAEs was achieved in the range of 50 to 4 000 ng/g. The proposed method was applied for analyzing different kinds of fat-containing samples. PAEs in commercial fat-containing samples can be highly extracted by a packed solid-phase extraction column of 5 mg polystyrene （ PS） nanofibers. The satisfactory average recoveries were obtained in the range of 96. 7% to 102. 3% , and the relative standard deviations （RSDs） below 5% were achieved. The proposed method reduces the organic solvent consumption, the complex and tedious procedures for sample pretreatment, and achieves high sensitivity and reproducibility for the investigated PAEs.

生物活性炭滤池对水源水中邻苯二甲酸酯的降解性能

研究活性炭滤池在挂膜期间对水源水中4种微量PAEs的降解情况,以及挂膜成功后的生物活性炭滤池及改变运行条件如空床停留时间、4种PAEs的进水浓度、反冲洗膨胀度对降解4种PAEs的影响。结果表明:未挂膜时,活性炭滤池对DMP、DEP、DBP和DEHP的去除率为77.41%、82.40%、88.87%和96.17%,挂膜成功后,生物活性炭滤池对DMP、DEP和DBP的去除率分别增至99.3%、100%和95.27%,而对DEHP的去除率降为61.9%。当生物活性炭滤池成功启动并稳定运行后,15 min的空床停留时间下能够去除进水中94%以上的DMP、DEP、DBP以及74%以上的DEHP;如果持续提高进水中4种PAEs的浓度,滤池对其去除率会相应降低;当反冲洗时滤池膨胀度大小为20%,生物活性炭滤池对4种PAEs的去除率不仅能快速恢复正常水平,且能维持更长时间。

Distribution and sources of polycyclic aromatic hydrocarbons and phthalic acid esters in water and surface sediment from the Three Gorges Reservoir

After the impoundment of the Three Gorges Reservoir（TGR）, the hydrological situation of the reservoir has changed greatly. The concentration and distribution of typical persistent organic pollutants in water and sediment have also changed accordingly. In this study, the concentration, distribution and potential sources of 16 polycyclic aromatic hydrocarbons（PAHs） and 6 phthalic acid esters（PAEs） during the water drawdown and impoundment periods were investigated in water and sediment from the TGR. According to our results, PAHs and PAEs showed temporal and spatial variations. The mean ΣPAH and ΣPAE concentrations in water and sediment were both higher during the water impoundment period than during the water drawdown period. The water samples from the main stream showed larger ΣPAH concentration fluctuations than those from tributaries. Both the PAH and PAE concentrations meet the Chinese national water environmental quality standard（GB 3838-2002）. PAH monomers with 2–3 rings and 4 rings were dominant in water, and 4-ring and 5–6-ring PAHs were dominant in sediment. Di-n-butyl phthalate（DBP） and di-2-ethylhexyl phthalate（DEHP）were the dominant PAE pollutants in the TGR. DBP and DEHP had the highest concentrations in water and sediment, respectively. The main source of PAHs in water from the TGR was petroleum and emissions from coal and biomass combustion, whereas the main sources of PAHs in sediments included coal and biomass combustion, petroleum, and petroleum combustion. The main source of PAEs in water was domestic waste, and the plastics and heavy chemical industries were the main sources of PAEs in sediment.

Abiotic association of phthalic acid esters with humic acid of a sludge landfill

The abiotic association between phthalic acid esters （PAEs） and humic substances （HS） in sludge landfill plays an important role in the fate and stability of PAEs. An equilibrium dialysis combined with 14C-labeling was used to study the abiotic association of two abundant PAEs （diethyl phthalate and di-n-butyl phthalate） with humic acid （HA） isolated from a sludge landfill with different stabilization times and different molecular weights. Ele- mental analysis and Fourier Transform Infrared Spectro- photometer （FTIR） suggested that high KA value of HA was related to the high aromatic content and large molecular weight of HA. The results indicated that the association strength of PAEs with HA depended on both the properties of the PAEs and the characteristics of HA. The KA values of the association were strongly dependent on solution pH, and decreased dramatically as the pH was increased from 3.0 to 9.0. The results suggested that non- specific hydrophobic interaction between PAEs and HA was the main contributor to the association of the PAEs with HA. The interactive hydrogen-bonds between the HA and the PAEs molecules may also be involved in the association.