十二烷基苯磺酸鈉懸浮多層奈米碳管偽靜相於電動層析分離核苷酸之應用

NaDDBs as a Dispersion Agent for Multi-Walled Carbon Nanotubes in Capillary Electrophoretic Separation of Nucleotides

謝語芳(Yu-Fang Hsieh)

指導教授 ： 劉春櫻 教授

國立臺灣大學/理學院/化學研究所/碩士(2009年)

https://doi.org/10.6342/NTU.2009.01033

摘要

奈米碳管與巴克球、石墨同為碳的同素異形體，為富勒家族 (fullerene family) 的一員，其管壁為捲起的富勒片 (fullerene sheet)，是六元碳環結構，閉管的兩端為五元碳環與六元碳環間隔排列的半圓巴克球。奈米碳管富有許特異的物理性，例如:高表面積、高機械應力、導電度佳等等。這些特別的性質使得奈米碳管成為分析技術研究上的新寵。本研究利用十二烷基苯磺酸鈉 (NaDDBs) 懸浮多層奈米碳管 (MWCNT) 作為毛細管電動層析的偽靜相用於分離核苷酸分子。NaDDBs 與一般常用於毛細管微胞電動層析 (MEKC) 的界面活性劑十二烷基磺酸鈉(SDS) 相比多了苯環結構，使其懸浮奈米碳管的能力較SDS高出兩個數量級，可有效減少奈米碳管的用量，進而降低基線雜訊。本研究探討奈米碳管與介面活性劑適當的比例、用量、緩衝液酸鹼度和濃度、有機修飾劑與外加電壓對於分離效果的影響。由於電滲流與分析物之電泳移動相反，本研究發現以8 mg L-1 NaDDBs懸浮 0.8 mg L-1 MWCNT於 30 mM, pH 8 磷酸緩衝液條件下，七種不同鹼基的核苷單磷酸同份異構物可達最佳分離效果。此分離選擇性來自於奈米碳管與分析物本身的疏水性作用力，分析物與奈米碳管間之π-π作用力，以及NaDDBs與分析物間之親水性作用力及氫鍵作用力等。而於50 mM, pH 9 磷酸緩衝液與樣品添加10%甲醇的條件下可於三十分鍾內分離十二個不同鹼基的單、雙和三磷酸核苷酸混合物。磷酸緩衝溶液濃度越高，波鋒半高寬越窄，滯留時間越短，分離效率提高，使得理論版數平均值為N=42276。

關鍵字

奈米碳管 ； 十二烷基苯磺酸鈉 ； 偽靜相 ； 電動層析 ； 核甘酸 ； 雞精 ； 物理性懸浮

並列摘要

Carbon nanotubes (CNTs) belong to the fullerene family of carbon allotropes. The walls of the tubes consist of hexagonal carbon, and the end caps contain pentagonal rings. Their specific physical properties, such as high surface areas and mechanical and electrical properties, make CNTs interesting to analytical science. In our work, a special type of MEKC, NaDDBs-coated MWCNTs EKC was used for the separation of biomolecules. Sodium dodecylbenzenesulfonate (NaDDBs) was used for the dispersion of carbon nanotubes. NaDDBs is composed of two parts: the long hydrophobic chain and the benzylsulfonate group. In comparison with the conventional surfactant used in MEKC, sodium dodecylsulfate (SDS), NaDDBs suspends more MWCNTs (about 100-fold) than SDS, and the π-π interaction between the benzene ring of NaDDBs and MWCNTs prolongs the slurry suspension time. Using NaDDBs as surfactant can reduce the required amount of MWCNTs and decrease the baseline noise. Even the system without micelle could make the good pseudostationary phase. To produce a stable suspension, various ratios (w/w) of MWCNTs to NaDDBs over the range from 1:10 to 1:20 were studied with turbidimetry. The ratio of 1:10 produces the most stable form. Considering this, several parameters affecting the CE separation were studied, including the amount of surfactant and of MWCNTs, the buffer pH, composition and concentration, as well as the organic modifier. The results show that 8 mg L-1 of NaDDBs-coated MWCNTs (0.8 mg/L) as the pseudostationary phase in a phosphate buffer (30 mM, pH 8) as the mobile phase could provide the best recognition for 7 nucleoside monophosphates, baseline separating even the geometric isomers. In the stacking mode, adding 10% MeOH to the sample mixture in a phosphate buffer (50 mM, pH 9) containing 0.8 mg L-1 MWCNTs and 8 mg L-1 NaDDBs, 12 model compounds, including nucleoside mono-, di- and tri-phosphates, were resolved. The nucleotides with a more electron-withdrawing functional group have a strong interaction with MWCNTs because of the π electron donor and π electron acceptor interaction. From the retention behavior of each analyte, the separation mechanism was suggested to be hydrogen bonding and a hydrophilic interaction between surfactant and analytes, as well as hydrophobic force and π-π interaction between MWCNTs and nucleotides, in addition to the electrophoretic mobility difference.

並列關鍵字

carbon nanotubes ； sodium dodecylbenzenesulfate ； MWCNT ； suspension ； nucleotides

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