PEAK-CAPACITY OF COLUMNS FOR SIZE-EXCLUSION CHROMATOGRAPHY

The practical peak capacity of columns for size-exclusion chromatography (SEC) is related to the pore fraction (V(p)/V(t)), plate number (N) and resolution (R(s)) and may be estimated from n(SEC) almost-equal-to 1 + V(p)/V(t)) N1/2/(4R(s)). This equation yields a value of 80-90% of the maximum peak capacity, in contrast to earlier proposed equations which yield a large overestimate of the peak capacity. The practical peak capacities of columns packed with microparticulate materials is ca. 13 for completely resolved peaks, which is roughly equal to the peak capacity of columns traditionally used for SEC, the reason being the small pore volume of rigid materials and the short column lengths used. However, the maximum peak capacity is obtained with a considerably shorter separation time.