# Plate Theory and Extensions - The Gaussian Form of the Elution Equation > Page 41

# The Gaussian Form of the Elution Equation

To change the Poisson form of the elution equation to the Gaussian form, it is necessary to change the position of the origin of the Poisson curve. Consider the elution curve as shown in Figure 9. The origin of the Poisson curve is the point of injection, whereas the origin of the Gaussian curve is at the peak maximum, which will be (n) plate volumes from the injection point.

Now, a point X, (v) plate volumes from the point of injection will be (v-n) = w plate volumes from the peak maximum. Consequently, v = (n+w). This change of origin is depicted in Figure 9.

Now, the Poisson form of the elution equation is as follows,

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**Figure
9. The Different Axes of The Poisson Elution Curve and the Gaussian
Elution Curve**