Kahle Kimberly A, Foley Joe P
Department of Chemistry, Drexel University, Philadelphia, PA 19104, USA.
Electrophoresis. 2006 Nov;27(21):4321-33. doi: 10.1002/elps.200600261.
The effect of cosurfactant identity on microemulsion size, elution range, retention factor, enantioselectivity, methylene selectivity, efficiency, and resolution in chiral microemulsion formulations was examined. The chiral surfactant dodecoxycarbonylvaline was used in conjunction with the cosurfactants 1-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, cyclopentanol, and cyclohexanol. The millimolar concentration of cosurfactant was held constant regardless of identity. Ethyl acetate was incorporated as the microemulsion oil core and the buffer utilized was 50 mM phosphate at a pH of 7.0. In general, secondary alcohols improved enantioselectivities and primary alcohols had the opposite effect, with the exception of the 1-butanol. The trends observed varied slightly depending on analyte. Of the six chiral analytes tested, cyclopentanol provided the best enantioselectivity for three, 1-butanol for two compounds, and 2-pentanol for one analyte. The lowest enantioselectivities were achieved with 1-pentanol or 1-hexanol for all compounds. Methylene selectivity was found to decrease with reductions in alcohol chain length. Among equal carbon number alcohols, methylene selectivity was lower for secondary alcohols. Efficiency and resolution values varied with different cosurfactants and depended on analyte identity.
考察了共表面活性剂种类对手性微乳液制剂中微乳液尺寸、洗脱范围、保留因子、对映体选择性、亚甲基选择性、效率和分离度的影响。手性表面活性剂十二烷氧基羰基缬氨酸与共表面活性剂1-丁醇、1-戊醇、2-戊醇、1-己醇、2-己醇、环戊醇和环己醇联合使用。无论种类如何，共表面活性剂的毫摩尔浓度保持恒定。乙酸乙酯作为微乳液油核，使用的缓冲液是pH为7.0的50 mM磷酸盐。一般来说，仲醇提高了对映体选择性，伯醇则有相反的效果，但1-丁醇除外。观察到的趋势因分析物而异。在所测试的六种手性分析物中，环戊醇对三种分析物提供了最佳的对映体选择性，1-丁醇对两种化合物提供了最佳的对映体选择性，2-戊醇对一种分析物提供了最佳的对映体选择性。所有化合物用1-戊醇或1-己醇时对映体选择性最低。发现亚甲基选择性随着醇链长度的减少而降低。在碳数相同的醇中，仲醇的亚甲基选择性较低。效率和分离度值因不同的共表面活性剂而异，并且取决于分析物种类。
