Comprehensive 2D-LC

In comprehensive 2D-LC (also known as LC×LC), the total eluent from the first dimension is injected on to the column in the second dimension using two equal-sized sampling loops that are alternated by a switching valve. While the first loop is being filled in the first dimension, the contents of the second loop is analyzed in the second dimension; the switching valve then switches the second loop into the first dimension for sampling and the first loop into the second dimension for analysis.

The gradient analysis in the second dimension is less than or equal to the sampling time in the first dimension: