where Vi represents the injection volume and 12 is a constant from assuming that the sample plug has a rectangular shape. Vi was calculated in units of time based on the flow rate and the path length of the sample plug. This mathematical expression represents the smallest possible contribution from the injection process. There have been other reports of additional contributions to band spreading from the injection valve due to dispersion inside the injection device [13,22,26,28]; however, these were not fully characterized either experimentally or theoretically. Therefore, we used LEM to empirically explore these phenomena.