Zhou D, Pietrzyk D J
University of Iowa, Chemistry Department, Iowa City 52242.
Anal Chem. 1992 May 1;64(9):1003-8. doi: 10.1021/ac00033a008.
The retention of alkanesulfonate and alkyl sulfate surfactants, which was determined on a reversed stationary phase as a function of mobile-phase ionic strength, is consistent with a double-layer type interaction at the stationary-phase surface. Increasing the mobile-phase ionic strength not only increases retention but also improves resolution because peak widths are significantly reduced. The type of cation provided by the ionic strength salt also enhances retention, reduces peak width, and improves resolution. Lithium hydroxide is an ideal electrolyte for the separation of multicomponent mixtures of alkanesulfonate and alkyl sulfate surfactants. When the column effluent is passed through a postcolumn anion micromembrane suppressor, the conductivity due to the electrolyte is minimized and conductivity detection is sensitive, yielding a detection limit of about 0.3 nmol of injected analyte for a 3:1 signal:noise ratio. Multicomponent alkanesulfonate and alkyl sulfate mixtures from C2 to C18 are baseline resolved by using a mobile-phase gradient whereby CH3CN concentration increases and LiOH concentration decreases.
在反相固定相上，根据流动相离子强度测定的链烷磺酸盐和烷基硫酸盐表面活性剂的保留情况，与固定相表面的双层型相互作用一致。增加流动相离子强度不仅会增加保留时间，还会提高分离度，因为峰宽会显著减小。离子强度盐提供的阳离子类型也会增强保留能力、减小峰宽并提高分离度。氢氧化锂是分离链烷磺酸盐和烷基硫酸盐表面活性剂多组分混合物的理想电解质。当柱流出物通过柱后阴离子微膜抑制器时，电解质引起的电导率会降至最低，电导率检测很灵敏，对于3:1的信噪比，注入分析物的检测限约为0.3 nmol。通过使用流动相梯度（其中乙腈浓度增加而氢氧化锂浓度降低），可实现C2至C18的链烷磺酸盐和烷基硫酸盐多组分混合物的基线分离。
