For complex biological samples—which often include analytes with a wide range in polarity and molecular weight, and many isomers—separations are often challenging, even when using ultrahigh-pressure liquid chromatography and high-resolution mass spectrometry. An example of this type of challenge arises in lipidomics, because lipids span a significant range of polarity and molecular weight as well as a substantial dynamic range; for example, one mL of human plasma contains lipids at a low femtomole level, as well as cholesterol, which is present in micromolar amounts.
For complex samples like these, it can be beneficial to use micro-chip based pillar array chromatography columns. In contrast to conventional LC columns that contain randomly packed beads as their stationary phase, micro-chip based pillar array chromatography columns have a separation bed of perfectly ordered and freestanding pillars obtained by lithographic etching of a silicon wafer. The regular mobile phase flow pattern through these micro-chip pillar array columns adds very little dispersion to the overall separation, resulting in better peak resolution, sharper elution peaks and increased sensitivity. The freestanding nature of the pillars also leads to much lower back pressure buildup, and makes it possible to operate longer columns.
In this webcast, Dr. Paul Jacobs of PharmaFluidics will explain the principles of the micro-chip based pillar array columns. Dr. Koen Sandra of the Research Institute of Chromatography (RIC) will show high resolution data obtained for lipidomic profiling of human blood serum using micro-chip based pillar array columns. |
