Open tubular columns minimum length

For practical reasons it is desirable to have only the minimum number of columns that will solve one s most frequent separation problems. Open tubular columns are so efficient that fewer of them are usually needed, but it is common to have two to four different phases and several different film thicknesses and lengths. More specific information is given in each of the respective chapters on packed and capillary columns. 

Figure 3 Progress of frontal zone under application of pulsed electric field. A pulsed electric field was applied in 2-s cycles (electric field was applied for half of the period, and was stopped for the other half). Frontal zone positions were measured from the digital picture on a CRT. The perpendicular line shows the direction of movement of the frontal zone, and 1 mm in length is equal to 167 pixels. The horizontal line shows the time, and the minimum time scale observed is equal to one-fifteenth. A round open-tubular capillary column 75 pm in diameter and 28 mm in length was used. Applied voltage, 1 50 V. Colored sample methanol solution of 1 mM Rhodamine 6G.

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