碩士 / 國立中央大學 / 化學研究所 / 96 / Hexabromocyclododecanes (HBCDs) is a nonaromatic brominated cyclic alkane which is widely used brominated flame retardants in the markets. HBCDs are used primarily as an additive in thermoplastic ploymers with final applications in styrene resins. It has also been used in textile coating, cable, latex binding and unsaturated polyesters. Since the production and applications of polybromodiphenyl ethers (PBDEs) have been banned or restricted in many countries, due to the high capability and relatively low production cost, HBCDs could be the best alternative for PBDEs in many applications. Recent studies have shown that HBCDs has a strong tendency to be bioaccumulate and high bioconcentration factor. It is also persistent in various environmental matrices. The commercial HBCD products are composed of three diastereomers: α-, β- and γ-HBCD.
Soxhlet extraction is the widely used for extraction organics from solid samples, however, it is time and solvent consuming. Newly developed pressurized liquid extraction (PLE) method is selective and non-solvent consuming technique, but "one time a sample" sequential procedure and possible restrictor blockage are its drawbacks. Recently, microwave-assisted extraction (MAE) has been developed to extract various pollutants from solid and biological tissue samples. MAE offers high throughput and relatively low-solvent consumption.
In this study, the effects of various operating parameters (i.e., composition of extraction solution, temperatures and times) for the quantitative extraction of HBCDs by MAE were systematically investigated and optimized. Three diastereomers (α-, β- and γ-HBCD) were then completely separated and quantitated by liquid chromatography – ion trap mass spectrometry (LC-IT-MS) with electrospray (ESI) in negative ionization mode. The HBCDs can be completely extracted by 40 mL of acetone/n-hexane (1/3, v/v) at 90 ?C with 12 min of extraction. Recovery of HBCDs in spiked sediment samples ranged from 51 to 98 % with 0.7–20 % RSD. Limits of quantitation (LOQs) were established between 30 and 40 pg/g (dry weight) in 5 g of sediment sample. The extraction efficiency of the MAE was also compared with Soxhlet extraction and PLE methods.
Furthermore, the accuracy and precision of the method were performed and the effectiveness of the method for the unequivocal determination of HBCDs in fish and sediment samples at trace-level has been demonstrated.
| Identifer | oai:union.ndltd.org:TW/096NCU05065015 |
| Date | January 2008 |
| Creators | Hsin-hung Wu, 吳信宏 |
| Contributors | Wang-hsien Ding, 丁望賢 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 119 |
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