Chromatography - The Chromatogram

Let's consider the output from the detector: the chromatogram. The figure below will help you to follow along in our discussion.

Since the sample is separated in the column, different peaks on the chromatogram correspond to different components in the sample mixture. The chromatograms above show the results of separations of protein mixtures by ion exchange chromatography. The lettered peaks correspond to different proteins (A = ovalbumin, B = conalbumin, C = cytochrome c, D = lysozyme). The separation corresponding to the chromatogram on the left was performed at pH 5.85, while the one on the right was performed at pH 6.5. It is evident that operation conditions such as pH and temperature have a significant effect on the output.

What Information Can Be Attained?

• The level of complexity of the sample is indicated by the number of peaks which appear.
• Qualitative information about the sample composition is obtained by comparing peak positions with those of standards.
• Quantitative assessment of the relative concentrations of components is obtained from peak area comparisons.
• Column performance is indicated by comparison with standards.

We have completed another segment of our journey! Have fun considering different types of chromatography.


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