• Application Note

Exact Control of Solvent Composition with the ACQUITY UPLC H-Class Quaternary Solvent Manager

Exact Control of Solvent Composition with the ACQUITY UPLC H-Class Quaternary Solvent Manager

  • Waters Corporation

This is an Application Brief and does not contain a detailed Experimental section.


The goal of this application brief is to determine the smallest adjustment in solvent composition available for controlling peak retention time with the quaternary solvent manager pumping module of the ACQUITY UPLC H-Class System.


The ACQUITY UPLC H-Class quaternary pump delivers solvent compositions adjustable in increments of 0.1% with predictable effect on retention time.


The exact control of solvent composition, blending of mobile phase components, and total flow rate are required to tune a separation for optimal resolution and peak identification using retention time.

It is, therefore, necessary to measure the ability of a system to accurately deliver compositions differing by a small percentage. With this information, confident development of robust methods is possible.

Results and Discussion

The ACQUITY UPLC H-Class System is based on a low pressure mixing, four-solvent pumping system that offers flexibility in solvent choice and delivery. To demonstrate how solvent composition and delivery can effect peak retention, a USP compendial method established for telmisartan and related compound A is used. Figure 1 shows the USP separation of telmisartan standard and related compound A run at organic composition set at 70%, according to USP assay guidelines.

Figure 1. Telmisartan standard and related compound A separation run with 70% organic solvent.

The percentage of organic solvent delivered is increased in 0.1% increments. The example shows the effect on retention time from 69.6% organic to 70.5% organic in an isocratic separation. Change in 0.1% organic increments results in a corresponding shift in the standard peak retention time. Figure 2 clearly demonstrates that changing the organic solvent delivered by 0.1% increments impacts the standard peak elution.

Figure 2. Influence of 0.1% adjustment of solvent composition on peak elution.


Control of flow rate, composition, and mixing are important characteristics of an LC pump. The foursolvent pumping unit of the ACQUITY UPLC H-Class System offers flexibility, and the ability to deliver solvent mixtures that differ by 0.1% composition. This capability can serve as a powerful tool to help identify optimal conditions for separating analytes in sample mixtures that are extremely sensitive to very small changes in organic composition.

720004405, July 2012

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