HPLC is the most commonly used analytical technique for separation of compounds in solution. This experiment investigates the effects of extra column volume (ECV) in HPLC experiments at various flow rates. ECV is important in chromatography because understanding it and how it affects HPLC results can help scientists to develop more efficient separation of samples. As flow rate is increased, the total system variance decreases. When the variance is decreased, the peaks are narrower and more analytes can possibly be separated and identified. It was found in these experiments that as the overall variance decreased, the percent of variance due to extra column volume increased. When this occurs, the separation becomes more difficult and the chromatographer is unable to take advantage of all the benefits of newer stationary phase technology since the ECV becomes a limiting factor. In this experiment it was confirmed that minimizing ECV diminishes this phenomena, but that once the ECV has been minimized to a certain degree that this effect can be removed. Our measurements were taken at extra column volumes of 90 and 60�L. Based on this data, it appears that the extra column volume can be optimized to diminish this effect. Based on calculations, for our system, this optimal volume would be 45�L.