Notice the graph is logarithmic not linear. There at two distinct positions on the curve the exclusion limit and the permeation limit. The exclusion limit defines the maximum molecular weight that can enter a pore, while the permeation limit signifies the minimum molecular weight to enter a pore. The curve itself is called the permeation region and this provides a range of molecular weights which could be found in the experiment. Retention time, how long the component spends in the column, is plotted against molecular weight. The peaks located in Figures 1 and 2 are similar to peaks liquid or gas chromatography readout. Normally peaks found in liquid or gas chromatography indicates how many components are in a mixture if the number of components is unknown and the relative amount of each component in the mixture within a given range. In the case of SEC these peaks indicate the relative amount of each component (based on molecular weight) within the permeation region. 