# Extra Column Dispersion - Rapid Separations Employing Gradient Elution > Page 55

Although the actual elution took only 22 seconds, due to the time required to form the gradient and regenerate the column the total gradient cycle was 5-6 minutes. To fully utilize the speed of the system a number of gradient storage columns would be necessary, that could be operated in parallel, if the gradient analysis was to be repeated continuously. The quantitative repeatability of the system was tested with 8 replicate analyses of the mixture. The results obtained are shown in Table 6. It is seen that despite the complexity of the analytical procedure, and the need for specialized apparatus, the majority of the components showed less than 3% standard deviation.

Furthermore, only two components had a standard deviation of 5%.