Merck Sharp & Dohme Corp./Merck Research Laboratories, 126 East Lincoln Av., Rahway, NJ 07065, USA.
Merck Sharp & Dohme Corp./Merck Research Laboratories, 126 East Lincoln Av., Rahway, NJ 07065, USA.
J Chromatogr A. 2014 Jul 25;1352:87-92. doi: 10.1016/j.chroma.2014.05.044. Epub 2014 May 28.
Commercially available ultra high pressure liquid chromatography (UHPLC) equipment offers the ability to explore the influence of backpressure on chromatographic separations. However, the influence of pressure on the chromatographic separation of enantiomers on chiral stationary phases remains largely unexplored. In this investigation we surveyed the effects of pressure on the separation of enantiomers using several reversed-phase chiral stationary phases. The experiments were conducted at constant flow rate and column temperature, using isocratic conditions. The only variable parameter was pressure, which was adjusted using a post-column backpressure regulator. For the separation of enantiomers on chiral stationary phases, an increase in pressure from approximately 2,000 psi (138 bar) to approximately 8,000 psi (552 bar) at constant flow rate and temperature led to an increase of retention factors for some analytes and a decrease for others. Achiral separations on a C-18 stationary phase always led only to an increase of retention factor. Interestingly, changes in pressure led to small changes in enantioselectivity during reversed-phase chiral separation of enantiomers, suggesting that such studies may be of value for better understanding the mechanisms underlying chromatographic enantioseparation.
市售的超高压液相色谱 (UHPLC) 设备能够探索背压对色谱分离的影响。然而，压力对手性固定相上对映体色谱分离的影响在很大程度上仍未得到探索。在这项研究中，我们调查了压力对几种反相手性固定相分离对映体的影响。实验在恒定流速和柱温下，采用等度条件进行。唯一的变量参数是压力，通过柱后背压调节器进行调节。对于手性固定相上对映体的分离，在恒定流速和温度下，压力从大约 2000psi（138 巴）增加到大约 8000psi（552 巴），导致一些分析物的保留因子增加，而另一些则减少。在 C-18 固定相上的非手性分离总是只导致保留因子增加。有趣的是，压力的变化在手性固定相上对映体的反相分离中导致对映选择性的微小变化，这表明此类研究可能有助于更好地理解色谱对映体分离的机制。
