The upper number is the temperature program limit. A column can be maintained at this temperature for 10-15 minutes without severely shortening column lifetime or experiencing excessively high column bleed. Exposing the column to higher temperatures or for longer time periods results in higher column bleed and shorter column lifetimes. Exceeding the upper temperature limits may damage the stationary phase and the inertness of the fused silica tubing. Column Capacity Column capacity is the maximum amount of a solute that can be introduced in to a column before significant peak distortion occurs.
Overloaded peaks are asymmetric with a leading edge.
Tailing peaks are obtained if a PLOT column is overloaded. No damage occurs if a column is overloaded. Column capacity is related to stationary phase polarity, film thickness, column diameter and solute retention. Higher column capacities are obtained for solutes that are similar in polarity to the stationary phase. For example, a polar column has a higher capacity for a polar solute than a non-polar solute.