Degassing Technology That Could Improve HPLC and Laboratory Efficiency
Industry Insight Mar 31, 2020
In the world of analytical chemistry, liquid chromatography (LC) has become indispensable in the analyst’s toolbox. Decades of research and refinement have brought many advances, in particular the dawn of high-performance liquid chromatography (HPLC). Incremental changes have enabled improved sensitivity, better resolving power, the ability to work with ever smaller sample volumes. Which begs the question, where else can improvements be made?
We spoke to Saba Jazeeli, Senior Product Manager at IDEX Health & Science, about the development of a novel degasser and the impact it could have on HPLC efficiency and optimizing processes in analytical labs.
Karen Steward (KS): What were the strongest drivers that led to the development of this latest degasser?
Saba Jazeeli (SJ): Since the emergence of LC in the 1970s, in-line degassers have become a standard component of most LC systems, and their development has not historically matched that of other components. Today, most degassers use tubular Teflon™ AF or polytetrafluoroethylene (PTFE) membranes. While in-line degassing prevents most issues surrounding solvent outgassing, as currently practiced, tubular degassers operating at a single, fixed vacuum setpoint do not address all the challenges associated with the removal of excess dissolved air from the mobile phase.
A key driver for designing a degasser to replace the current tubular design was to reduce membrane wall thickness. By improving the vacuum degasser flow channel design, users are able to achieve higher efficiency degassing, in a more streamlined device that sustains the use of crucial materials such as Teflon™ AF. In HPLC separations, the reduction of dissolved air from the mobile phase is of critical importance to the baseline and pump flow rate stability, simultaneously reducing the effect of degassing on mobile phase composition, and, accordingly, to the chromatographic separation stability and proper identification of compounds separated by the HPLC method. Reducing compositional changes to the mobile phase and maintaining sufficient degassing were the key drivers for our latest product. We have redesigned the degasser to improve efficiency and keep pace with LC and HPLC technology innovation.
Another consideration that led to the development of the degasser was that current users are restricted by the intricacies of tubular-based degasser design. Currently, numerous iterative design elements such as wall thickness, length and ID of tubing, all with the correct combination of parameters, are needed for optimal performance for each instrument type and design. Additionally, productivity and efficiency are affected as current HPLC instruments are optimized for a wide range of flow rates. At low flow rates, optimization and adjustments are likely to be needed for each HPLC system and method. The universality and flexibility afforded by flat film degassers, as a single solution, eliminates concerns over multiple vacuum chambers for various HPLC applications and improves consistency in performance.
KS: Are there any particular challenges that you have come up against in the design and development process?
SJ: A vacuum degasser is commonly manufactured using a tubular-based design. Wall thickness (membrane diffusion path) cannot be too thin otherwise the degassing coil will kink during manufacturing. The ID (fluid diffusion path) cannot be so small that flow restriction within the degasser becomes problematic. Therefore, we wanted to design a flat film membrane that would meet the levels of degassing efficiency that are currently in the market and, ideally, exceed these. The biggest challenge was to design an optimized fluid housing for minimal carry over and a robust vacuum housing that ensured uniform flow distribution. The entire solution had to offer low fluidic resistance and high efficiency, all while being biocompatible. To achieve this, our main focus was creating a thin membrane and a short fluid diffusion path.
KS: How do you foresee this development benefiting scientists in the laboratory? In which areas are the most gains likely to be seen?
SJ: For any analytical laboratory, the primary goal is to optimize processes and increase efficiency. Productivity gains can be achieved for labs across the HPLC workflow through the highly effective, thinner flat film membrane degasser technology. Many labs face space limitations, so the compact design of flat film devices aligns with the need for increasingly small instrument footprints. Furthermore, in terms of practical use, the simple design of flat film degassers, with no fittings or connections, minimizes the likelihood of system failure and improves the integrity of the device.
Uniform flow is another significant benefit of the flat film degasser. Optimum degassing solutions achieve any level of performance, for any flow rate, within the range of applied vacuum. In the first instance, the degassing channel should meet the performance requirements of any analytical scale HPLC system. Simultaneously, the degasser should minimize the movement of solvent vapors across the membrane – a process known as pervaporation – to reduce concentration changes in mixed mobile phases and, at the same time, minimize the amount of solvent vapor discharged into the laboratory atmosphere.
The film degasser is enhanced by our vacuum control methodology for constant performance, which allows for advanced control in order to select the optimal degassing efficiency for any HPLC separation method. This enables consistent operation to reduce pervaporation and associated mobile phase concentration changes. It also provides the user with the ability to integrate the degasser into the separation method control protocol and select a given efficiency for any HPLC system, which they can then dial up or down to get the exact specification they need for any application.
The introduction of flat film membranes into the market represents a significant step forward for the industry and is likely to improve the efficiency of analytical laboratories in the future.
KS: Environmental impact and sustainability are increasingly important considerations for laboratories. Are there any features or design considerations that you would like to highlight where the new degasser offers environmental or sustainability improvements?
SJ: The IDEX Flat Film Degasser offers a versatile, high performance system that is suitable for universal applications. It eliminates the design limitations of tubular-based degassers, delivering reduced pervaporation and a lower environmental impact by controlling the discharge of solvent vapors to the laboratory atmosphere, therefore lowering the lab’s environmental impact. The reduction of pervaporation from pre-mixed mobile phases also leads to a more consistent chromatography.
Moreover, increased solvent compatibility and the intelligent control of the applied vacuum offers one solution for multiple HPLC applications in a single instrument.
Saba Jazeeli was speaking to Dr Karen Steward, Science Writer for Technology Networks.