以官能基奈米碳管偽靜相應用於非類固醇抗炎性藥物的毛細管電泳分離

Abstract

本研究係以羧化多層奈米碳管(multi-walled carbon nanotubes containing carboxyl groups, c-MWNTs)為緩衝溶液添加物，於毛細管電泳中扮演偽靜相的角色，應用於非類固醇抗炎性藥物(non-steroidal anti- inflammatory drugs, NSAIDs)之分離。由於奈米碳管屬於疏水性，利用硝酸/硫酸混合溶液經過超音波震盪進行氧化反應，藉由FT-IR、ESCA和TEM之方法鑑定，發現最佳作用時間為4 h，成功使奈米碳管表面官能基化來提升水溶性且保留奈米碳管完美的管狀結構。奈米碳管為黑色物質會干擾UV偵測，所以本實驗緩衝溶液中c-MWNTs含量為0.02 mg/ml。經由比較硼酸緩衝溶液與磷酸緩衝溶液的穩定性，發現硼酸緩衝溶液可輔助c-MWNTs懸浮。因此，以硼酸緩衝溶液(75 mM, pH 10)添加0.02 mg/ml c-MWNT再利用有機修飾劑(MeOH, EtOH, 1-pro- panol, 2-propanol, 1-butanol)來提升解析度，發現分析物滯留時間延長，電流值變小，而且隨著碳鏈的增加，c-MWNTs的穩定度下降，分析物的解析度也降低，其中以5 % MeOH的效果最好。本研究並且發現低溫有助於其解析度的提升。在硼酸緩衝溶液(75 mM, pH 10)添加0.02 mg/ml c-MWNTs和5 % MeOH於電壓12 kV低溫進樣(0℃)，滯留時間為：indoprofen < ketoprofen < suprofen < fenoprofen < flurbiprofen < naproxen，平均理論板數為8.6×104 m-1，分析物滯留時間的RSD值為2.22% (n = 3)，而羧化多層奈米碳管可提供π - π interaction、hydrophobic interaction、electrostatic interaction和hydrogen bond。本研究並與MEKC (75 mM borate buffer, 50 mM SDS, pH 10)比較，發現滯留時間為suprofen < naproxen < ketoprofen < fenoprofen < indoprofen < flurbiprofen，平均理論板數為3.6×104 m-1，分析物滯留時間的RSD值為1.85% (n = 3)。本研究以c-MWNTs 作為偽靜相，相較於MEKC具有高理論板數和多樣性作用力，可以成功分離六種pKa值相近的非類固醇抗炎性藥物。

A functionalized multiwalled carbon nanotubes (c-MWNTs) as a pseudostationary phase for the capillary eletrophoretic separation of non-steroidal anti-inflammatory drugs (NSAIDs) was described. In order to increase hydrophilicity of the multiwalled carbon nanotubes (MWNTs) in an aqueous electrolyte, a sonochemical process was used to treat MWNTs in concentrated nitric/sulfuric acid mixture. Fourier transform infrared spectroscopy (FTIR), transmission electron microscopy (TEM), and electron spectroscopy for chemical analysis system (ESCA) were used for the characterization of the oxidized MWNTs. The c-MWNTs afforded sieving mechanism, π-π interaction, hydrophobic interaction, hydrogen bond, and electrostatic interaction to separate NSAIDs, providing a different separation mode from sodium dodecyl sulfate (SDS) micelles. The effect of important factors such as pH and concentration of running buffer, separation voltage, organic modifiers and injection temperature were investigated to acquire the optimum conditions. The optimum experimental conditions for the separation of a drug mixture, which consisted of indoprofen, ketoprofen, suprofen, naproxen, flurbiprofen and fenoprofen were using a mixture of borate buffer (75 mM, pH 10)-methanol (95:5, v/v) containing 0.02 mg/ml c-MWNTs as background electro- lyte by low injection temperature and an applied voltage of +12 kV with UV detection at 214 nm. The separation of these drugs could be achieved with an average plat number of 8.6×104 m-1. Finally, the procedure was applied to analyze NSAIDs spiked in urine sample with satisfactory results.