Using active flow technology columns to achieve near 'direct' injection through-put in HPLC-MS

A new column technology referred to as active flow technology was used to undertake the analysis of amino acids at very high through-puts. Using active flow technology chromatography columns functioning in a parallel segmented flow mode the separation efficiency was shown to be up to 65% higher than conventional columns - based on the number of theoretical plates. Since the volumetric flow that elutes from the active flow technology column is reduced in proportion to the segmentation ratio, the volume of mobile phase that enters the mass spectrometer is reduced. This enables separations to be undertaken at higher volumetric flow rates without compromising the flow limitations of the MS. When 2.1. mm i.d. active flow technology columns were employed separations with MS detection were completed in less than 6 s, time scales that rival those for direct injection, but with the advantage of having a chromatographic separation step prior to the MS.