Performance attributes of the ExionLC 2.0+ system ultrahigh pressure liquid chromatography system

Flow stability and injection performance

Adrian M. Taylor
SCIEX, Canada


The ExionLC 2.0+ system is a flexible and robust UHPLC system that is suitable for today’s fast LC-MS workflows. High retention time precision is demonstrated, enabling large scale time scheduled quantitative assays, with excellent autosampler injection linearity and precision.



Increasing demands on the modern-day laboratory require finding ways to increase analytical throughput and expanding the lab’s sample capacity. Mass spectrometry has become a popular analytical tool in many labs and liquid chromatography is still the most common sample introduction technology for high-quality up-front analyte separation prior to mass spectrometry. Ultrahigh pressure liquid chromatography, using sub 2 µm column particle packing, provides the ability to run fast baseline separation of compounds with minimal equilibration times, aiding in both time and cost reductions over conventional liquid chromatography.

As the sensitivity, speed and selectivity of mass spectrometers continually improves, faster, more powerful LC-MS workflows are achievable when the full potential of UHPLC is leveraged. In this technical note, the key performance attributes of the SCIEX ExionLC 2.0+ system were investigated, specifically the flow rate precision and resulting retention time reproducibility for fast separation analysis. As is typical, the injection linearity and precision were studied. A SCIEX 5500+ system coupled with an ExionLC 2.0+ system was chosen as the test LC-MS/MS platform. To allow for direct LC pump and autosampler performance investigations, an integrated (optional) ExionLC 2.0+ diode array detector HS was used for ultraviolet-visible (UV-Vis) detection experiments.

Figure 1. Retention time precision for high pressure analysis.  Overlaid ultraviolet-visible traces from 100 repeat injections of the same standard Supelco HPLC gradient diagnostic mix, using the ExionLC 2.0+ system operating at 1100 bar (16,000 psi). The retention time stability for this test across the 100 injections was <0.15 % RSD.

Key features of the ExionLC 2.0+ system

  • Dual high-pressure serial piston pumps, rated to 1240 bar (18,000 psi) at flow rates of 0.001 to 5 mL/min, for maximum flexibility in running fast gradient separations and maximizing laboratory throughput
  • The ability to accommodate a wide range of UHPLC columns, notably those with sub 2-µm column particle packing, making it possible to run fast baseline separations of compounds with minimal equilibration times, when compared to conventional liquid chromatography
  • Novel camshaft geometry pumps providing precise, durable and stable solvent flow delivering less than 0.15% relative standard deviation (RSD) retention time variation, maximizing result consistency and assay uptime
  • A fully automated piston pump simplifying method setup with linear movement that is adjusted automatically, in real time, and reduces pulsation to very low levels that are independent of flow rate, backpressure and eluent type
  • A function for automatically purging the flow lines with mobile phase, allowing streamlined changeover between different methods
  • Accurate and precise quantification results, with injection linearity performance of r > 0.999 and precision <1% CV for low injection volumes from 0.5 to 5 µL for confidence in reporting compound amounts present