| Polycyclic aromatic hydrocarbons (PAHs) and phthalate esters (PAEs) are semi-volatile organic pollutants widespread in the environment. PAEs is widely used in commercial, medical, and personal care products as plasticizer. PAEs may cause endocrine, reproductive and developmental toxicity. Most of the materials and reagents used in the laboratories can leach PAEs, which causes relatively high blank and background levels of PAEs during PAEs analysis. Therefore, it is necessary to reduce the pollution of PAEs during the process of PAEs monitoring in food samples. Gas Purge Micro-Syringe Extraction (GP-MSE) is a new sample pretreatment technology. It only needs a few milliliters of organic solvent, does not require adsorbent or other material, and target compound extraction completed in a few minutes under the protection of inactive nitrogen and a series of equipment, which is no plastic material inside of it. It have high extraction efficiency and good sample purification ability for volatile/semi-volatile compounds, suitable for the detection of trace organic pollutants. In this study, using GP-MSE sample pretreatment techniques, we developed a new convenient sample pretreatment method for trace organic pollutants monitoring in atmosphere, food, plant samples, which can eliminate or lower background PAEs levels, and investigated the level and characteristics of PAHs and PAEs in actual samples. The main results are as follows:1) Low background PAEs analysis method was developed, and levels and characteristics of PAEs in domestic market food samples were investigated. Nowadays, the largest problem in PAEs analysis is the high blank value due to widespread application of PAEs in various products. To overcome this shortcoming, GP-MSE was applied, which established a new and low-blank-value analytical method for PAE analysis in foodstuffs. In this study, GP-MSE was used as a clean-up method, and the overall recoveries ranged from 85.7 to 102.6%, and the RSD was less than 10%. This method can overcome the problem of the high blank value in PAE analysis. New method was applied for measuring PAEs in 78 foodstuffs. The results showed that a wide range of PAE concentrations in different group food samples. The highest concentrations of PAEs (varies from 658 to 1610 ng/g fresh weight) was found in seafood. The individual concentrations of PAEs were in the following order:DEHP> DBP> DEP≈DMP> BBP≈DNOP. Finally, the daily intake of PAEs for adults was estimated based on the levels of PAEs in foodstuffs. The estimated total EDI diet values of DEHP for the mean and highest concentrations in foodstuffs, were 3.2 and 12.9 mg kg-1 bw d-1, respectively.2) A sensitive concentration method for gas phase samples was developed using modified GP-MSE with a microlitre volume, and continuous monitoring of atmospheric PAHs was conducted. PAHs were used as semi-volatile compounds to optimize the various parameters that affect the concentration efficiency of target compounds. The injection rate and temperature were the key factors that affected the concentration efficiency. An efficient concentrations (75.0-96.1%) of PAHs were obtained under the optimized conditions. The method exhibited good reproducibility (RSD values that ranged from 1.5 to 9.0%). The GP-MSE concentration method enhances the volume reduction (concentration factor), leading to a low method detection limit (0.5-15 ng/L). Furthermore, this method offers the advantage of small-volume sampling, enabling even the detection of diurnal hourly variations of PAHs in ambient air. This method combined GC-MS, could achieve continuous monitoring of hourly variations of gas phase PAHs in ambient air. In conclusion, the proposed technique is a simple, fast, low-cost and environmentally friendly.3) A simple and fast sample pretreatment method for PAHs analysis in tree leaves was developed, and temporal distributions of PAH concentrations in tree leaves of Saliz matsudana during whole growing period were investigated. Saliz matsudana leaves were collected from bud break to leave falls (May-November 2013). Atmospheric gas phase and particulate PAHs was collected using a high volume air sampler. Six kinds of PAHs, ubiquitous in atmospheric gas phase, were determined in Saliz matsudana leaves samples. The effect of foliar parameters (leaf area, lipid content, specific surface area), meteorological conditions (temperature, precipitation) and levels of atmospheric PAH to the seasonal variations of PAHs in Saliz matsudana leaves were investigated. Results showed that PAHs in Saliz matsudana leaves showed clear seasonal variations. The lowest levels was 88.3 ng/g (dry weight) found in spring, the highest levels was 542.3 ng/g (dry weight), found in the final sample collected in autumn. Contributions of individual PAHs to the total PAHs in Saliz matsudana tree leaves are as following:Phenanthrene> fluorene> fluoranthene> pyrene> acenaphthene> anthracene. The variation trend of concentrations of phenanthrene and the total PAHs were very similar (R2= 0.9389). Therefore, phenanthrene can be used as indicator of local temporal and spatial distributions of total PAHs. Compared with FLO, PYR and ANT, the proportions of ACE and FLU are higher in summer than in spring and autumn, indicate that the pollution sources of PAHs effected the composition of PAHs. The parameters of tree leaves, such as lipid content, surface area and specific surface area were not the key factors in effecting the PAH concentrations in tree leaves during whole growth period of Saliz matsudana. The variations of total PAHs and congener profiles in Saliz matsudana leaves and air samples were similar (R2= 0.7094). It implies that PAHs in Saliz matsudana leaves can be a good indicator of atmospheric gas phase PAHs. |
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