Related Experiment Video
Updated: Jun 26, 2026

Non-contact, Label-free Monitoring of Cells and Extracellular Matrix using Raman Spectroscopy
Published on: May 29, 2012
Characterization of carbon dioxide mobile phase density profiles in packed capillary columns by Raman microscopy
L Robert Baker1, Andrew W Orton, Steven R Goates
1Department of Chemistry and Biochemistry, Brigham Young University, Provo, Utah 84602, USA.
Abstract:
Efforts to understand and optimize separations employing compressible mobile phases have been limited by a lack of understanding of the mobile phase density gradient. Mobile phase compressibility leads to gradients in linear velocity and solute retention and affects separation speed and efficiency, especially in packed columns. Gas chromatography (GC), supercritical fluid chromatography (SFC), and solvating gas chromatography (SGC) each rely on compressible mobile phases. This work describes the on-column density measurement of carbon dioxide, a common carrier fluid for SFC and SGC, in packed capillary columns using Raman microspectroscopy of the position of the Fermi doublet. Correlation of the spectrum with density was calibrated over a pressure range of 15 to 290 atm at 125 and 150 degrees C, which then allowed for determination of the density gradient of fluid flowing through a packed capillary column. The results of this work will be used to model the flow behavior of compressible fluids to understand the effects of mobile phase compressibility on separation speed and efficiency.
More Related Videos
09:46Direct Comparison of Hyperspectral Stimulated Raman Scattering and Coherent Anti-Stokes Raman Scattering Microscopy for Chemical Imaging
Published on: April 28, 2022
07:51Combining Raman Imaging and Multivariate Analysis to Visualize Lignin, Cellulose, and Hemicellulose in the Plant Cell Wall
Published on: June 10, 2017
Related Concept Videos
Gas Chromatography: Types of Columns and Stationary Phases
For an analyte to remain on the column for a sufficient amount of time, it must exhibit some level of compatibility (or...
Raman Spectroscopy: Overview
However, a small fraction of the scattered light exhibits a frequency shift due to the exchange of energy between the incident photons and the...
Raman Spectroscopy Instrumentation: Overview
The monochromatic laser source, typically using visible or near-infrared radiation, generates a highly focused beam of light. This light interacts with the molecules of the sample, scattering some of the light. Liquid and gaseous samples are usually tested in ordinary glass capillaries, while solids can be analyzed as powders packed in capillaries or as potassium...
Diffusion on Chromatography Columns
Longitudinal diffusion occurs when the solute molecules in the mobile phase diffuse from the more concentrated center of the chromatographic band to the more dilute regions on either side, both towards and against the flow direction. This...
Gas Chromatography: Introduction
In GC, a sample is vaporized and mixed with an inert carrier gas (the mobile phase), which transports it through a column.
Gas Chromatography–Mass Spectrometry (GC–MS)
A gas chromatograph consists of a long, narrow capillary column with a polysiloxane coating on the inner wall. The coating...