A variable column length strategy to expedite method development.

A variable length method development (or VL-MD)strategy, exploiting the potential of an automatic column coupling system, is proposed and has been applied to a number of different pharmaceutical and environmental samples with a varying degree of complexity. The proposed strategy consistently produced separation methods that had at least an equally good critical pair resolution and an equally short run time to those of methods produced using commercially available MD assistance software. In some cases, the VL-MD strategy allowed the MD time to be drastically shortened from >30 h to an overnight run of only 12 h. The developed strategy has the potential to become fully automated provided that reliable chromatogram read-out software becomes available. The advantage of combining different stationary phase types to improve the available selectivity and the integration into the general VL-MD strategy was also demonstrated.