In the U.S., countercurrent distribution is usually referred to as the Craig distribution after the man who, along with Post, developed the most successful device for the process. The process, which will be discussed in more detail later, is discontinuous and is exactly analogous to carrying out a pattern of extractions in separatory funnels. Some major advantages are

While progressive dilution of the sample occurs, longitudinal diffusion does not occur and does not contribute to peak spreading.

Polar substances are easily handled.

Using automatic apparatus, high resolution is possible.

Apparatus up to kilogram capacity is available.