Mechanistic understanding of abnormal reverse phase chromatographic behavior of basic analytes in the presence of sodium dodecyl sulfate

• Published in: Journal of Chromatography A Vol. 1595; pp. 108 - 116
• Main Authors: Socia, Adam, Liu, Yong, Abend, Andreas, Wuelfing, W. Peter
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 21-06-2019
• Subjects: Basic analytes; Peak splitting; Retention time shifting; Reverse phase chromatography; Sodium dodecyl sulfate (SDS); Surfactant; Basic analytes; Peak splitting; Reverse phase chromatography; Sodium dodecyl sulfate (SDS); Surfactant; Retention time shifting
• ISSN: 0021-9673
• DOI: 10.1016/j.chroma.2019.02.044

•Interaction of SDS in sample solution with basic analytes in RPLC was explored.•Micelle concentration and strength found to be the origin of the peak splitting.•Modifications to pH or instrument configuration can affect the amount of splitting.
In the process of dissolution method development for Merck proprietary compound A, a basic analyte, abnormal chromatographic behavior involving peak splitting and retention time shifting in the presence of sodium dodecyl sulfate (SDS) in the sample solution was observed. A mechanistic study was conducted and the level and type of surfactant, along with the pKa of the analyte, were determined to be the critical variables in the degree of effect seen. Chromatographically, the effect was further impacted by the injection volume used, the pH and identity of the mobile phase buffer and the amount of system volume between the autosampler and the column. A simple resolution using a basic mobile phase pH was identified to be an effective way to eliminate abnormal chromatographic behavior and produce robust and reproducible analysis.