HPLC/UHPLC Technical Tip
Level: Basic
Basic Analytes and the Use of High pH Stable Stationary Phases
The development of hybrid materials has greatly extended the high pH stability of HPLC sorbents. This new development allowed users to use high pH to deprotonate basic compounds, increasing their hydrophobicity (and hence retention) whilst also removing the possibility of ion exchange.
This approach is particularly useful when considering polar basic compounds as the combination of good peak shape with enhanced retention is useful, especially in LC-MS/MS where elution under higher organic mobile phase conditions has been shown to be beneficial for peak response. Columns such as Gemini™ and Kinetex™ EVO can be used in the pH range 1-12.
Lidocaine (peak 3) run at pH 12 on a Twin technology, high pH stable material.
Other Technical Resources
Basic Compounds by LC/MS using a High pH Mobile Phase
We investigate the effectiveness of using high pH mobile phases for the quantitation of basic compounds in ESI+ LC/MS/MS by comparing limits of detection (LOD), limits of quantitation (LOQ), linearity ranges, precision, and accuracy observed in high and low pH mobile phases.
Using pH-LC to Control Selectivity of Acidic and Basic Compounds by HPLC
We investigate the effectiveness of using pH-LC techniques in the separation of a mixture of acidic (naproxen), basic (amitriptyline), and neutral (toluene) compounds using a Gemini 5 µm NX-C18 column.
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Gemini and Kinetex are trademarks of Phenomenex.
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