Rah Kyunil, Han Sujeong, Choi Jaeyeong, Eum Chul Hun, Lee Seungho
188 Moonji-ro, IT & E Materials R&D, LG Chem, Daejeon, 34122 South Korea.
Department of Chemistry, Hannam University, Daejeon, 34054 South Korea.
J Chromatogr A. 2017 Dec 15;1528:75-82. doi: 10.1016/j.chroma.2017.10.078. Epub 2017 Nov 7.
We investigate an explicit role of the ionic strength in the retention behaviors of polystyrene (PS) latex particles in sedimentation field-flow fractionation (SdFFF) by hinging upon the retention theory recently developed [1] asR=(R+v)/(1+v). Here R is an experimental retention ratio, and R is the analytical expression of the standard retention theory based on the parabolic flow velocity. The reduced boundary velocityv is expressed in terms of the ionic strength I of the carrier liquid as v=v/(1+εI), where v=0.070and ε=60 mM for all the PS latex systems under investigation. We then apply this to study the explicit ionic strength effect on the retention behaviors of PS beads of 200, 300, 400, and 500nm, respectively. As a primary result, the strong dependence of the retention ratio on the ionic strength can be quantitatively accounted for in an excellent accuracy: The slip effect at the channel surface is significant, particularly when I≲0.5mM, without showing any distinguishable dependence on the specific additives to control I, such as FL-70, SDS, NaNO, and NaN. Based on the present study, we put forward an experimental means to estimate the ionic strength of an aqueous solution using an FFF technique.
我们依据最近提出的保留理论[1]，即R=(R+v)/(1+v)，研究了离子强度在沉降场流分离（SdFFF）中对聚苯乙烯（PS）乳胶颗粒保留行为的明确作用。这里R是实验保留率，R是基于抛物线流速的标准保留理论的解析表达式。折合边界速度v根据载液的离子强度I表示为v=v/(1+εI)，对于所有研究的PS乳胶体系，v = 0.070且ε = 60 mM。然后我们应用此式分别研究离子强度对200、300、400和500nm的PS珠保留行为的明确影响。作为主要结果，保留率对离子强度的强烈依赖性能够以极高的精度进行定量解释：通道表面的滑移效应显著，尤其是当I≲0.5mM时，且未表现出对用于控制I的特定添加剂（如FL - 70、SDS、NaNO和NaN）有任何明显依赖性。基于本研究，我们提出了一种使用场流分离技术估算水溶液离子强度的实验方法。
