Gert Desmet
Full Professor, Vrije Universiteit Brussel, Belgium, and member of the EAB for LCGC Europe
Separation Science: The State of the Art: The Future of Column Packing Technology
December 1st 2022In this extended special feature to celebrate the 35th anniversary edition of LCGC Europe, key opinion leaders from the separation science community explore contemporary trends in separation science and identify possible future developments.
LC Column Technology: The State of the Art
November 1st 2017In this extended special feature to celebrate the 30th anniversary edition of LCGC Europe, leading figures from the separation science community explore contemporary trends in separation science and identify possible future developments. We asked key opinion leaders in the field to discuss the current state of the art in liquid chromatography column technology, gas chromatography, sample preparation, and liquid chromatography instruments. They also describe the latest practical developments in supercritical fluid chromatography, 3D printing, capillary electrophoresis, data handling, comprehensive two‑dimensional liquid chromatography, and multidimensional gas chromatography.
Comparing the Separation Speed of Contemporary LC, SFC, and GC
June 1st 2017Some 50 years after Giddings’s iconic comparison of the separation speed of gas chromatography (GC) and liquid chromatography (LC), the authors revisit this comparison using kinetic plots of the current state‑of‑the-art systems in LC, supercritical fluid chromatography (SFC), and GC. It is found that, despite the major progress LC has made in the past decade (sub-2-µm particles, pressures up to 1500 bar, core–shell particles), a fully optimized ultrahigh-pressure liquid chromatography (UHPLC) separation is still at least one order of magnitude slower than capillary GC. The speed limits of packed bed SFC are situated in between.
(U)HPLC: The Shape of Things To Come
May 1st 2017A recent argument was raised in the scientific press that in pursuit of greater speed and separation resolution, ultrahigh performance liquid chromatography (UHPLC) is faced with practical limitations and will struggle with its own version of Moore’s law.
Generic UHPLC Method for the Simultaneous Analysis of Compounds with a Wide Range of Polarities
June 7th 2016Appropriate analytical methods are required to evaluate the presence, metabolism, degradation, and removal of specific compounds in complex mixtures. There is an increasing demand to analyze samples with a wide range of polarities in a variety of applications, including environmental analysis, biomarker discovery, and proteomics. Multiple analyses on complementary columns are often needed to cover the separation of all compounds with a large difference in polarity. This article describes a generic method involving an ultrahigh‑pressure liquid chromatography (UHPLC) system equipped with two external switching valves to connect hydrophilic interaction liquid chromatography (HILIC) and reversed-phase LC columns in series for the sequential analysis of polar and apolar compounds.
Generic UHPLC Method for the Simultaneous Analysis of Compounds with a Wide Range of Polarities
April 19th 2016Appropriate analytical methods are required to evaluate the presence, metabolism, degradation, and removal of specific compounds in complex mixtures. There is an increasing demand to analyze samples with a wide range of polarities in a variety of applications, including environmental analysis, biomarker discovery, and proteomics. Multiple analyses on complementary columns are often needed to cover the separation of all compounds with a large difference in polarity. This article describes a generic method involving an ultrahigh-pressure liquid chromatography (UHPLC) system equipped with two external switching valves to connect hydrophilic interaction liquid chromatography (HILIC) and reversed-phase LC columns in series for the sequential analysis of polar and apolar compounds. The method was successfully applied to separate 32 pharmaceutical compounds with a wide range of polarities, which could be useful for analyzing pharmaceutical compounds in the environment.
Are Short Columns Always The Best Option?
February 1st 2009Using a fixed length-variant of the kinetic plot method, it is illustrated how an analysis that is performed near the optimal flow-rate of a given commercial column can, in many cases, be performed between 50–200% faster by switching to a longer column and operating it at a higher pressure - at least, if the available instrument pressure admits so. The present article aims to show that short columns are not always the best choice to get the fastest separation.
Comparison Techniques for HPLC Column Performance
June 1st 2008This article investigates the different methods that can be used to compare the performance of liquid chromatography (LC) columns to assess the advantage of using them at high pressures and/or high temperatures. The main focus is on the kinetic plot method. This method, which is based on two simple equations, allows the user to transform the more common Van Deemter curve into a curve describing the ultimate separation speed as a function of the required plate number, or the required peak capacity or the required resolution.
Comparison Techniques for HPLC Column Performance
June 1st 2008This article investigates the different methods that can be used to compare the performance of liquid chromatography (LC) columns to assess the advantage of using them at high pressures and/or high temperatures. The main focus is on the kinetic plot method. This method, which is based on two simple equations, allows the user to transform the more common Van Deemter curve into a curve describing the ultimate separation speed as a function of the required plate number, or the required peak capacity or the required resolution.
Pressure-driven Chromatography in Perfectly Ordered Pillar Array Columns
April 1st 2007his article reveals the first liquid chromatography (LC) separations performed on a microfabricated pillar array column under pressure-driven conditions. The pillars were non-porous and produced using a Bosch-type deep reactive ion etch (DRIE) to pattern the surface of a silicon wafer and had a diameter of approximately 5 μm. Two different packing densities were compared: one similar to the packing density of a packed bed (external porosity of approximately 49%) and one similar to the packing density of monolithic columns (external porosity of approximately 70%).
Shear-Driven Flow LC: Dispensing with Pumps and Voltage Supplied for Increased Speed and Resolution
May 1st 2004The authors discuss the application of shear-driven chromatography, a technique that depends on viscous drag to propel mobile phase in high-resolution/high-speed liquid chromatography. This method, it is claimed, overcomes the pressure- and voltage-drop limitations of both HPLC and CEC. Early development of the technique is reviewed and updated with the current status of the group's work. Also covered are the challenges faced and opportunities available to interface such systems to MS and UV/vis absorption detectors.