At HUPO 2011 in Geneva, the Human Proteome Organization introduced attendees to the latest protein-related technologies. For one thing, pharmaceutical scientists want more ways to use liquid chromatography (LC) with peptides and proteins, and this interest will expand as more companies explore biologics.
One example of new proteomics-related technology unveiled at HUPO was a line of column chips for the cHiPLC-nanoflex system from Eksigent, a division of AB SCIEX (Dublin, Calif.). A scientist can add this system to any Eksigent nanoLC system, and the company introduced five new chips. They include columns and trap columns packed with C4—a four-carbon hydrophobic alkyl chain—for analyzing intact proteins, such as antibodies.
As explained by Remco van Soest, director of product management at Eksigent: “We’ve focused on peptide separations on chips in the past. With more and more biologics in development, we’re now developing chip columns for intact protein analysis.” The new chips also include C18-packed columns and trap columns for peptides, and a larger internal diameter gives these columns higher throughput and sample loading. The 200 µm–internal diameter C18-CL micro cHiPLC columns come in 5- and 15-cm lengths, and they can run at flow rates of 1.0 to 3.5 µL per minute. Tina Settineri, PhD, director, HLPC products and assistant general manager at Eksigent, points out that “our 200 micron–internal diameter chips are run at higher flow rates than our 75-micron chips, which are run at typical nanoLC flow rates.” She adds: “This reduces delay time, enabling big increases in throughput.”
Eksigent also offers a range of products for microLC, such as the ExpressHT-Ultra, which works with 0.3 to 1 mm–internal diameter columns. This platform, says van Soest, provides “a microLC system for fast separations at UHPLC [ultra high pressure liquid chromatography] pressures.” In comparison to systems that run larger diameter columns, says van Soest, a microLC system saves solvent, reduces the solvent load on the mass spectrometer, and provides similar or increased sensitivity.
Academic labs make up the main market for these Eksigent systems, but Settineri says the company “also sells to biotech and pharma and is looking to expand further in this space with both microLC and nanoLC systems.” This new chip technology will appeal to a range of researchers, the company reports, because the chips are comparable in cost to commercially packed columns but more convenient to use.
Taming the transition
Moving old LC methods to new platforms still creates challenges for researchers. “In drug development and quality control, there are still lots of legacy methods running on conventional HPLC systems,” says Michael Frank, PhD, marketing manager for analytical systems at Agilent (Santa Clara, Calif.). “On the Agilent 1290 Infinity UHPLC,” says Frank, “you can run old legacy HPLC methods and new UHPLC ones.”
In moving a method from HPLC to UHPLC, research goes from a larger capillary and delay volume to smaller capillaries and delay volumes. Consequently, using an HPLC method on a UHPLC can generate different results.
To overcome such challenges, Agilent developed its Intelligent System Emulation Technology (ISET), which enables the use of methods from lots of instruments. A scientist inputs a legacy method on the 1290, picks an instrument to emulate from a dropdown menu, and the 1290 optimizes the legacy method for UHPLC assays. So far, the 1290 emulates previous Agilent systems, and the company will add third-party instruments. As Frank says, “There’s no need to determine different delay volumes of the different systems, no need to change existing legacy methods.”
That all makes for a smooth transition.
About the Author
Mike May is a publishing consultant for science and technology based in Austin, Texas.