At the end of the column they elute one at a time. During the entire chromatography process the eluent is collected in a series of fractions. Fractions can be collected automatically by means of fraction collectors. The productivity of chromatography can be increased by running several columns at a time.
dash - the act of moving with great haste; he made a dash for the door bolt rush, rushing, haste, hurry - the act of moving hurriedly and in a careless manner; in his haste to leave he forgot his book
A dash is a punctuation mark, a long horizontal line which is used to make a long break, rather like an ellipsis. A pair of dashes can be used to show someone interrupting the flow of a sentence to talk to someone else.   A dash is also a name for a short burst of running or a short sprint race.