High efficiency HPLC with long packed columns

Coupling several 25 cm × 2 mm ID analytical columns together is a simple and easy way to achieve high resolution HPLC (20,000–50,000 plates). How to do this with commercially available instruments, injectors and detectors is described in the paper. An attractive feature of the long narrow column approach is that the same HPLC set-up can be used for both fast-low and slow-high efficiency separations. High efficiency is essential for really complex natural mixtures, e.g. the hop and beer bitter acids. Some examples are shown.