Aniline Oligomers or Imidazolium-Based Ionic Liquid Crystals as Coating Materials in Solid-Phase Microextraction Fibers for Benzene, Toluene, Ethylbenzene, Xylenes (BTEX) Analysis

Autor: Chih-Tsung Chen, 陳志宗
Rok vydání: 2012
Druh dokumentu: 學位論文 ; thesis
Popis: 100
Aniline oligomers and ionic liquid crystals (ILCs) are first designed as coating materials for headspace solid-phase microextraction (HS-SPME) to extract benzene, toluene, ethylbenzene, xylenes (BTEX) and analyze BTEX by using gas chromatography-mass spectrometry (GC-MS). Aniline oligomers as sorbent materials coating on TiO2 nanotubes fiber for BTEX analysis is applied. Aniline tetramer shows superior efficient than other oligoanilines such as dimer, 8-mer, 16-mer, and polyaniline. The optimal conditions are as follow: extraction temperature, extraction time, desorption temperature, salt, coating amount, coating layer are 60 °C, 1 min, 180 °C, 0.4 g, 0.05 mg, and 1 layer, respectively. Under the optimal conditions, the detection limits (LODs) of BTEX are 0.0001-0.01 μg L-1 and the linear ranges are 0.001-40000 μg L-1 (R2 ≥ 0.9962). The RSD were 4.7-7.9 % (one fiber, n = 5), 5.3-9.3 % (fiber-to-fiber, n = 3). The great storage and operational stabilities are found that no significantly response decreasing of the fiber on 5 months storage at room temperature and 80 times consecutive operations. The recoveries of real samples are 96.6-102.6 %. A series of imidazolium-based ionic liquid crystals (ILCs) as sorbent materials coating on Ti wire as SPME fiber is applied. [C1, EC16-Im] [PF6] shows superior efficient than other ILCs such as [C1, C16-Im] [Br], [C16, C16-Im] [Br], [C16, EC16-Im] [Br], [C16, EC1-Im] [Br], [C1, EC12-Im] [PF6], [C1, EC14-Im] [PF6], [C1, EC16-Im] [Br], [C1, EC16-Im] [BF4]. The optimal conditions are as follow: extraction temperature, extraction time, desorption temperature, salt, pre-treatment temperature, pre-heat time, coating amount, coating layer are 60 °C, 3 min, 180 °C, 0.4 g, 180 °C, 30 min, 0.4 mg, and 1 layer, respectively. Under the optimal conditions, the detection limits (LODs) of BTEX are 0.0001-0.01 μg L-1 and the linear ranges are 0.001-40000 μg L-1 (R2 ≥ 0.9956). The RSD were 2.7-4.8 % (one fiber, n = 5), 3.5-6.1 % (fiber-to-fiber, n = 3). The great storage and operational stabilities are found that no significantly response decreasing of the fiber on 5 months storage at room temperature and 68 times consecutive operations. The recoveries of real samples are 96.9-101.1 %. This work demonstrates two materials, aniline tetramer-based and [C1, EC16-Im] [PF6]-based fibers with high selectivity, good precision and accuracy, long lifetime, low cost, and high stability. This method analysis each sample is about 10 minutes that showing high throughput for BTEX analysis.
Databáze: Networked Digital Library of Theses & Dissertations
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