The tutorial focuses on the power of multidimensional liquid chromatography (MDLC) for the separation of mixtures too complex to be resolved in a single separation step.MDLC can take on two basic modes: one is the "heart-cut method" where only a single fraction (or a limited number of fractions) from the first separation dimension (D1) is subject to the second dimension (D2); in contrast, the most recently developed "comprehensive mode" is performed when each component in the first dimension is subject to the second dimension of separation.As a result, the major benefit is that the separation capacities of each dimension are multiplied, offering a high peak capacity to resolve samples of great complexity.