Chromatographic Peak Shape (ideal):

At the injection point a mixture of analytes are injected into the column, more or less as a plug. The concentration of the analytes in this plug us essentially uniform throughout. Thus a plot of concentration along the length of the column will look like;

The above concentration vs time/carrier gas volume is close to the real injection profile. The ideal profile is expected to be infinitely thin. It is the objective of the experimenter to make the injection as thin as possible.

Within the column the thin band broadens (many factors contribute to band broadening), and an ideal broadened band will take a Gaussian shape. The separated analytes emerge from the column as bands with a Gaussian concentration profile. The detector detects analyte moving through it at a given instant. It will generate a signal (as a function of time) proportional to the amount of analyte. Thus an ideal chromatographic peak will take a Gaussian shape.

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