Analysis of basic compounds at high pH values by reversed-phase liquid chromatography

Area of Science:

• Analytical Chemistry
• Chromatography

Background:

• Reversed-phase high-performance liquid chromatography (RPHP LC) is standard for basic compound analysis.
• Silica-based stationary phases exhibit secondary interactions with residual silanols, causing peak tailing and affecting analytical outcomes.
• These interactions include ion exchange, hydrogen bonding, and London forces, compromising resolution, sensitivity, and reproducibility.

Purpose of the Study:

• To evaluate the chromatographic behavior of a bidentate stationary phase (Zorbax Extend C18) for analyzing basic compounds.
• To investigate the efficacy of high pH mobile phases in mitigating secondary interactions.
• To compare the performance of the bidentate phase with other supports under high pH conditions.

Main Methods:

• Utilized reversed-phase high-performance liquid chromatography (RPLC).
• Employed a bidentate stationary phase, Zorbax Extend C18.
• Conducted analyses using a high pH mobile phase with basic and neutral compounds.
• Compared performance against traditional silica supports.

Main Results:

• The bidentate stationary phase demonstrated high chemical stability, enabling high pH mobile phase usage.
• High pH mobile phases effectively reduced secondary interactions between basic analytes and the stationary phase.
• The Zorbax Extend C18 phase proved advantageous for analyzing basic compounds at high pH.

Conclusions:

• High pH mobile phases are a viable alternative to acidic conditions for reducing secondary interactions in RPLC.
• The bidentate stationary phase offers superior chemical stability for high pH applications.
• Employing high pH mobile phases with suitable stationary phases significantly improves the analysis of basic compounds.