| Perfluorinated compounds (PFCs) have been widely used in the industry, for example, surfactants, lubricants, and pesticides due to their unique high surface activity, thermal and acid resistance, hydro-and lipophobic properties. However, recent studies have proved that the continuous release of these substances from various applications and products has rendered them to become ubiquitous in the environment. Concern about PFCs is growing because their potentially harmful. In this dissertation, we aimed to investigate the distribution and transport of PFCs to the atmospheric environment in order to better understand the environmental fate, potential risk assessment for the local inhabitantsIn this study, based on high-performance liquid chromatography (HPLC) tandem triple quadrupole mass spectrometry, was developed for detection of PFCs in aerosol. Perfluorinated compounds were extracted from particles by solvent extraction. The total concentration of PFCs in the samples ranged from 0.2 to 55 ng/m3 which varied with seasons. The back trajectories showed air masses of autumn came from the northwest of China, while air masses of spring mainly came from ocean areas or surrounding areas. Which indicated that air masses from different orientation could influence the concentrations of PFCs in PM2.5. There were some positive correlations among PFCs compounds.Three dimensional excitation emission matrix (3DEEM) fluorescence spectroscopy was used to investigate the composition and transformation of dissolved organic matter (CDOM) from PM2.5 and rain samples.3DEEMs spectra showed 4 types of fluorescence signals in samples. There were some positive correlations among between humic-like materials and protein like materials which indicated that they might have the same sources and nature.Since humic acids (HAs) could be able to adsorb and affect final fate of the hydrophobic organic contaminants in the water, this paper explored whether HAs could affect contaminants’migration and transformation in aerosol. We found that there were some negative correlations between PFCs and humic acids. This fact indicted that HAs could interact PFCs by the hydrogen bond or chemical reaction.The results of this thesis help the relevant departments to master the current contamination status of PFCs and dissolved organic matter in the atmosphere in our country. Meanwhile, it could provide scientific basis for related environmental risk evaluation and formulating laws and regulations of controlling PFCs pollution.During the period of studying for master, I also explored the sample pre-treatment technology. A novel method, based on desorption corona beam ionization (DCBI) tandem mass spectrometry (MS), was developed for the direct detection of bisphenol A in food packaging materials with minimal sample pretreatment. We optimized DCBI-MS conditions (i.e. extraction solvent and ionization source) using representative bisphenol A standards. The reagent solvent was methanol at high voltage (-2000 V, negative ion detection mode). The temperature of the heated capillary was optimized to be 225 ℃. The flow rate of He was 1.0 L/min. The limit of detection (LOD) of these amino acids was in the range of 0.1 mg/L, and the linear dynamic range 1-100 mg/L was larger than two orders of magnitude. The bisphenol A concentration in food packaging materials samples was measured by the method, and the average time for a single sample analysis was less than 30 s. The recovery rates for different concentrations ranged from 94% to 125%, and the relative standard deviation (RSD) was less than 17%. This study showed that DCBI-MS was a powerful tool for the rapid, sensitive, and quantitative detection of bisphenol Aamino acids in complex meterials samples. |
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