摘要 本研究應用毛細管電泳間接偵測的方法主要分離兩種未含有發色團的四級銨鹽界面活性劑，分別為直鏈式烷基三甲基銨鹽類( ATMACs )與直鏈式二烷基二甲基銨鹽類( DADMACs )。最有效的分離條件是緩衝溶液為10 mM磷酸鹽類，在pH值為4.35，添加有機修飾劑57.5%的四氫口夫口南( THF ) 與陰離子型界面活性劑修飾劑3 mM十二烷基硫酸鈉( SDS )，樣品利用水動式進樣法以壓力1 psi進樣20秒( 進樣體積約59.33 nL )，所施加電壓為25仟伏。為了改進波峰的定性與定量，針對發色團與內標準品的選擇做系統性的研究。其中氯化10-烷基苯基二甲基銨鹽( C10-BDMAC )為本實驗中最佳化的發色團，其與3 mM十二烷基硫酸鈉( SDS )結合對於此類的陽離子型界面活性劑可提供良好的偵測。毛細管電泳分析有良好的再現性，線性範圍為1.0到20.0 μg/mL，且線性關係係數( r2 )均大於0.999。本實驗的內標準品溴化8-四烷基銨鹽( TOA+B- )可增進遷移時間與定量上的再現性，其相對標準偏差( RSD )相對遷移時間均小於0.8%，與相對波峰面積其範圍為2.5~5.5%。此方法成功的應用到商業化的產品潤髮乳與衣物柔軟精中陽離子型界面活性劑的分析。本研究並利用電灑游離法質譜設備( ESI-MS )確認真實樣品中陽離子型界面活性劑之成分。 Abstract This investigation describes the simultaneous separation of two major non-chromophoric quaternary ammonium surfactants, alkytrimethyl and dialkydimethyl ammonium compounds ( ATMACs and DADMACs, respectively ), by capillary electrophoresis ( CE ) with indirect UV detection. The most effective separation condition was 10 mM phosphate buffer with 57.5% tetrahydrofuran and 3 mM SDS at pH 4.35, and the sample hydrodynamic injection of up to 20 sec at 1 psi ( approximately 59.33 nL ), and an applied voltage 25 kV. The selection of appropriate chromophore and internal standard to improve the peak identification and quantitation was systematically investigated. Decylbenzyldimethyl ammonium chloride ( C10-BDMAC ) as a chromophore wih 3 mM SDS provided the best detectability for all homologues. The reproducibility of the migration time and quantitative analysis can be improved by using tetraoctylammonium bromide ( TOA+B- ) as an internal standard, giving the relative standard deviation ( RSD ) less than 0.8% for the relative migration times, and 2.5 to 5.5% for the relative peak areas. A good linearity of CE analysis was obtained in the range of 1.0 to 2.0 μg/mL with r2 values of above 0.999. The analysis of cationic surfactants in commercial products of hair conditioners and fabric softeners was also performed. Electrospray mass spectrometric method ( ESI-MS ) was applied to evaluate the CE method , and the compatible results were obtained.
