Active Flow Technology (AFT) is a new HPLC column platform in which the flow of the mobile phase as it passes through the column can be dynamically managed to eliminate wall effects, minimise solute band broadening, maximise signal response or maximise theoretical plates has been introduced. The concept of this technology is to counter the lack of radial homogeneity that is associated with packed columns, in particular near the walls where the rigid structure the column housing does not facilitate a homogenous packing arrangement for solid spherical particles. The effects that radial inhomogeneity has in terms of column performance have been well described by numerous researchers.
The use of this technology has been solely applied to spherical particles packed into a stainless steel tubes. With this configuration of hardware and using the active flow technology, it has been demonstrated that the efficiency and the signal intensity can be improved. To date this technology has not been coupled to monolithic stationary phases, which suffer from the same physicalities in terms of flow profile as with a column packed with spherical particles. This presentation will address this, presenting data from a monolithic column and two different configurations of the AFT. It will be demonstrated that improvements in chromatographic efficiency of up to 50% can be achieved. By using the same hardware at the front end of the column it is possible to create a virtual column, where similar performance benefits can be realised, but also with an increase in sensitivity. Data will be presented from this alternative AFM configuration which demonstrates an increase in sensitivity of greater than 100%.