Figure 2.

Generic scheme of a loop-based, passive-modulation interface for use in 2D-LC. As the ¹D effluent is sampled by one loop, the contents of the other loop are, without any further modification, injected into the second dimension. In the configuration shown, the loops are filled and emptied in opposite directions (“backflush” mode). The scheme shows an 8-port valve, but a 10-port valve can also be used.^26,27 In (multiple) heart-cut 2D-LC, the loops can be replaced by “decks” each containing an array of sampling loops to allow storage of more than one fraction.